The 100 most-cited articles in Inorganic Chemistry, 2023

Zeolitic imidazolate frameworks (ZIFs) are a subclass of reticular structures based on tetrahedral four-connected networks of zeolites and minerals. They are composed of transition-metal ions and imidazolate-type linkers, and their pore size and shape, surface area, and functionality can be precisely controlled. Despite their potential, two questions remain unanswered: how to synthesize more diverse ZIF structures and how ZIFs differentiate from other crystalline solids. In other words, how can we use our understanding of their unique structures to better design and synthesize ZIFs? In this Review, we first summarize the methods for synthesizing a wide range of ZIFs. We then review the crystal structure of ZIFs and describe the relationship between their structure and properties using an in-depth analysis. We also discuss several important and intrinsic features that make ZIFs stand out from MOFs and discrete molecular cages. Finally, we outline the future direction for this class of porous crystals.

The conversion of diluted CO 2 into tunable syngas via photocatalysis is critical for implementing CO 2 reduction practically, although the efficiency remains low. Herein, we report the use of graphene-modified transition metal hydroxides, namely, Ni X Co 1– X -GR, for the conversion of diluted CO 2 into syngas with adjustable CO/H 2 ratios, utilizing Ru dyes as photosensitizers. The Ni(OH) 2 -GR cocatalyst can generate 12526 μmol g –1 h –1 of CO and 844 μmol g –1 h –1 of H 2, while the Co(OH) 2 -GR sample presents a generation rate of 2953 μmol g –1 h –1 for CO and 10027 μmol g –1 h –1 for H 2 . Notably, by simply altering the addition amounts of nickel and cobalt in the transition metal composite, the CO/H 2 ratios in syngas can be easily regulated from 18:1 to 1:4. Experimental characterization of composites and DFT calculations suggest that the differing adsorption affinities of CO 2 and H 2 O over Ni(OH) 2 -GR and Co(OH) 2 -GR play a significant role in determining the selectivity of CO and H 2 products, ultimately affecting the CO/H 2 ratios in syngas. Overall, these findings…

Electrocatalysts play a pivotal role in advancing the application of water splitting for hydrogen production. This research unveils the potential of defective biphenylenes as high-efficiency catalysts for the hydrogen evolution reaction. Using first-principles simulations, we systematically investigated the structure, stability, and catalytic performance of defective biphenylenes. Our findings unveil that defect engineering significantly enhances the electrocatalytic activity for hydrogen evolution. Specifically, biphenylene with a double-vacancy defect exhibits an outstanding Gibbs free energy of −0.08 eV, surpassing that of Pt, accompanied by a remarkable exchange current density of −3.08 A cm –2, also surpassing that of Pt. Furthermore, we find the preference for the Volmer–Heyrovsky mechanism in the hydrogen evolution reaction, with a low energy barrier of 0.80 eV. This research provides a promising avenue for developing novel metal-free electrocatalysts for water splitting with earth-abundant carbon elements, making a significant step toward sustainable hydrogen production.

The simultaneous realization of sustainable energy and gas sensors dealing with the emission of pollutants is indispensable as the former thrives on the minimization of the latter. However, there is a dearth of multifunctional nanocatalysts in the literature. This ascertains the importance of multifunctional semiconductors which can be utilized in H 2 generation via overall water splitting and in the gas sensing of global pollutants such as NH 3 . MoO 3 -decorated TiO 2 Z-scheme heterostructures exceptionally escalate the photochemical and photo/electrochemical H 2 evolution performance and gas sensing response of TiO 2 owing to the synergistic relationship between TiO 2 and MoO 3 . Extensive structural, morphological, and optical characterizations, theoretical studies, and XPS results were exploited to develop a mechanistic framework of photochemical H 2 evolution. The photochemical response of the optimum TiO 2 –MoO 3 composition (20 wt % MoO 3 –TiO 2 ) was found to be nearly 12- and 20-fold superior to the pristine TiO 2 and MoO 3 photocatalysts, respectively, with the remarkable…

Given the global warming caused by excess CO 2 accumulation in the atmosphere, it is essential to reduce CO 2 by capturing and converting it to chemical feedstock using solar energy. Herein, a novel Cs 3 Bi 2 Br 9 /bismuth-based metal–organic framework (Bi-MOF) composite was prepared via an in situ growth strategy of Cs 3 Bi 2 Br 9 quantum dots (QDs) on the surface of Bi-MOF nanosheets through coshared bismuth atoms. The prepared Cs 3 Bi 2 Br 9 /Bi-MOF exhibits bifunctional merits for both the high capture and effective conversion of CO 2, among which the optimized 3Cs 3 Bi 2 Br 9 /Bi-MOF sample shows a CO 2 –CO conversion yield as high as 572.24 μmol g –1 h –1 under the irradiation of a 300 W Xe lamp. In addition, the composite shows good stability after five recycles in humid air, and the CO 2 photoreduction efficiency does not decrease significantly. The mechanistic investigation uncovers that the intimate atomic-level contact between Cs 3 Bi 2 Br 9 and Bi-MOF via the coshared atoms not only improves the dispersion of Cs 3 Bi 2 Br 9 QDs over Bi-MOF nanosheets but also accelerates…

Creation of rich open metal sites (defect) on the nodes of metal–organic frameworks (MOFs) is an efficient approach to enhance their catalytic performance in heterogeneous reactions; however, direct generation of such defects remains challenging. In this contribution, we developed an in situ green route for rapid fabrication of defective MOF-808(Zr) with rich Zr-OH/OH 2 sites (occupying 25% Zr coordination sites) and hierarchical porosity without the assistance of formic acid and solvent. The optimal MOF-808(Zr) not only displayed superior activity in oxidative desulfurization (ODS) for removing 1000 ppm sulfur at ambient temperature within 20 min but also could convert 3.8 mmol of benzaldehyde to (dimethoxymethyl)benzene within 90 s at 30 °C. The turnover frequencies reached 45.4 h –1 for ODS and 3451 h –1 for acetalization, outperforming the most reported MOF-based catalysts. Theoretical calculation and experimental results show that the formed Zr-OH/OH 2 can react with H 2 O 2 to generate peroxo-zirconium species, which readily oxidize the sulfur compound. Our work provides a new…

Photocatalytic H 2 evolution has recently attracted much attention due to the reduction of nonrenewable energy sources and the increasing demand for renewable sustainable energies. Meanwhile, metal–organic frameworks (MOFs) are emerging potential photocatalysts due to their structural adaptability, porous configuration, several active sites, and a wide range of performance. Nevertheless, there are still limitations in the photocatalytic H 2 evolution reaction of MOFs with higher charge recombination rates. Herein, a copper–organic framework with dual-functionalized linkers {[Cu 2 (L)(H 2 O) 2 ]·(5DMF)(4H 2 O)} n (fluorinated MOF(Cu)-NH 2; H 4 L = 3,5-bis(2,4-dicarboxylic acid)-4-(trifluoromethyl)aniline) and with a rare 2-nodal 4,12-connected shp topology has been synthesized by a ligand-functionalization strategy and evaluated for the photocatalytic production of H 2 to overcome this issue. According to the photocatalytic H 2 evolution results, fluorinated MOF(Cu)-NH 2 showed a hydrogen evolution rate of 63.64 mmol·g –1 ·h –1 exposed to light irradiation, indicating values 12 times…

The introduction of high-entropy and high specific surface area into Prussian blue analogues (PBAs) has yet to create interest in the field of electrocatalytic small-molecule oxidation reactions. Herein, we synthesize a novel class of high-entropy (HE) PBAs with a high specific surface area via a simple NH 3 ·H 2 O-etching strategy and systematically investigate the electrocatalytic performance of HE-PBA toward electrocatalytic water, ethanol, and urea oxidation reactions. Importantly, the NH 3 ·H 2 O-etched HE-PBA (denoted as HE-PBA-e) demonstrated enhanced electrocatalytic performance toward small-molecule oxidation compared to the pristine HE-PBA, reaching 10 mA cm –2 with potentials of 1.56, 1.41, and 1.37 V for the oxygen evolution reaction (OER), ethanol oxidation reaction (EOR), and urea oxidation reaction (UOR), respectively. Deep characterizations suggest that the NH 3 ·H 2 O etching treatment not only creates rich nanopores to enlarge the surface area and boosts the mass transport and electron transfer but also facilitates the formation of high-valence metal oxides to…

To date, non-contact luminescence thermometry methods based on fluorescence intensity ratio (FIR) technology have been studied extensively. However, designing phosphors with high relative sensitivity ( S r ) has become a research hotspot. In this work, Eu 3+ single-doped Ca 2 Sb 2 O 7:Eu 3+ phosphors with a high S r value for dual-emitting-center luminescence thermometry are developed and proposed. The anti-thermal quenching behavior of Eu 3+ originating from the energy transfer (ET) of host → Eu 3+ is found and proved in the designed phosphors. Interestingly, adjustable color emission from blue to orange can be achieved. Surprisingly, the degree of the anti-thermal quenching behavior of Eu 3+ gradually reduces from 240 to 127% as the Eu 3+ doping content increases from 0.005 to 0.05 mol, attributed to most Eu 3+ being located in the low symmetrical [Ca1O 8 ] dodecahedral site. According to the differentiable responses of the host and Eu 3+ to temperature, the maximal S r value reaches 3.369% K –1 (383 K). Moreover, the ambient temperature can be intuitively predicted by observing…

Broadband near-infrared (NIR) phosphors are the critical component of phosphor converted NIR light-emitting diode (LED) light sources. However, there are still a lack of NIR phosphors with excellent external quantum efficiency (EQE) and thermal stability. Here, we report a highly efficient broadband NIR phosphor Y 3 Ga 3 MgSiO 12: Cr 3+ . The optimized phosphor yields an internal quantum efficiency (IQE) and an EQE of 79.9 and 33.7%, respectively. The integrated emission intensity still remains at 84.4% of that at room temperature when heated to 423 K. A broadband NIR LED lamp was made by combining as-prepared phosphor and a blue InGaN LED chip, which shows an output power of 89.8 mW with a photoelectric conversion efficiency of 17.1% driven at 525 mW input power. Our research provides a promising NIR phosphor with high efficiency broadband for the NIR light source.

Designing of heterojunction photocatalysts with appropriate interfacial contact plays crucial roles in enhancing the interfacial charge transfer/separation. A two-dimensional (2D)/2D face-to-face heterojunction is an ideal option since this architecture with a large contact area can provide abundant reactive centers and promote the interfacial charge transfer/separation between layers. Herein, a novel 2D/2D heterojunction of NiFe-layered double hydroxides (NiFe-LDH)/Cs 2 AgBiBr 6 (CABB) was fabricated by electrostatic self-assembly of NiFe-LDH and CABB nanosheets. This unique 2D/2D architecture endowed NiFe-LDH/CABB with a large contact area and a short charge transport distance, assuring remarkable interfacial charge transfer/separation rates. As a result, the 2D/2D NiFe-LDH/CABB heterojunction exhibited significant improvement in photocatalytic CO 2 reduction under visible light than the pristine counterparts. Based on density functional theory calculations and various characterizations, a step scheme charge-transfer mechanism was proposed. This investigation sheds light on the…

Molybdenum phosphide (MoP) has received increasing attention for the hydrogen evolution reaction (HER) due to its Pt-like electronic structure and high electrical conductivity. In this work, a flake-like Ru-doped MoP with phosphorus vacancy (Ru-MoP-P V ) electrocatalyst is synthesized for the first time by a simple and rapid room-temperature microwave approach within 30 s. The created abundant phosphorus vacancies provide rich active sites and favor rapid electron transfer. The introduced Ru also enhances the catalytic activity of the synthesized electrocatalyst efficiently. Then, the designed Ru-MoP-P V possesses low overpotentials for HER with 79, 100, and 161 mV in 1.0 M KOH, 0.5 M H 2 SO 4, and 1.0 M phosphate-buffered saline to obtain 10 mA cm –2 . The Ru-MoP-P V and NiFe-layered double hydroxide are used as the cathode and the anode, respectively, to drive water splitting and just need a low cell voltage of 1.6 V to achieve 10 mA cm –2 . This work provides a feasible way for the rapid production of metal phosphides for energy conversion and storage applications.

Solar-driven high-efficiency conversion of CO 2 with water vapor into high-value-added alcohols is a promising approach for reducing CO 2 emissions and achieving carbon neutrality. However, the rapid recombination of photogenerated carriers and low CO 2 adsorption capacity of photocatalysts are usually the factors that limit their applicability. Herein, a series of low-cost Z-scheme heterostructures Cu 2 O/PCN-250- x are constructed by in situ growth of ultrasmall Cu 2 O nanoparticles on PCN-250. A systematic investigation revealed that there is a strong interaction between Cu 2 O nanoparticles and PCN-250. The resulting Cu 2 O/PCN-250-2 exhibits excellent photogenerated carrier separation efficiency and CO 2 adsorption capacity, which dramatically promote the conversion of CO 2 into alcohols. Notably, the total yield of 268 μmol g cat –1 for the production of CH 3 OH and CH 3 H 2 OH is superior to that of isolated PCN-250 and Cu 2 O. This study provides a new perspective for the design of a Cu 2 O nanoparticle/metal–organic framework Z-scheme heterojunction for the reduction of CO…

Developing high-efficiency, low-cost, and earth-abundant electrocatalysts toward the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) is highly desirable for boosting the energy efficiency of water splitting. Herein, we adopted an interfacial engineering strategy to enhance the overall water splitting (OWS) activity via constructing a bifunctional OER/HER electrocatalyst combining MoS 2 –Ni 3 S 2 with NiFe layered double hydroxide (NiFe-LDH) on a nickel foam substrate. The NiFe-LDH/MoS 2 –Ni 3 S 2 /NF electrocatalyst delivers superior OER/HER activity and stability, such as low overpotentials (220 and 79 mV for OER and HER at current densities of 50 and 10 mA cm –2, respectively) and a low Tafel slope. This excellent electrocatalytic performance mainly benefits from the electronic structure modulation and synergistic effects between NiFe-LDH and MoS 2 –Ni 3 S 2, which provides a high electrochemical activity area, more active sites, and strong electron interaction. Furthermore, the assembly of NiFe-LDH/MoS 2 –Ni 3 S 2 /NF into a two-electrode system only…

With the introduction of Eu 3+ ions as the secondary fluorescent signal reporter and sensing active sites, a dual-emission ratiometric sensor of Eu 3+ @NiMOF (Eu 3+ functional NiMOF ) for hippuric acid (HA) detection in urine and serum was fabricated via the postsynthetic encapsulating strategy. Based on the two emission signals at 441 nm (turn-on) and 628 nm (turn-off), the produced Eu 3+ @NiMOF ratiometric sensor provided enhanced sensitivity, higher selectivity, and 9.7 times lower limits of detection (LOD) for the detection of HA (2.38 μM, 0.42 μg·mL –1 ) than that of the pristine NiMOF . Considering the high sensitivity and visualization results, further exploration of intelligent applications in the HA sensing process was carried out by constructing a tandem combinational logic gate to improve the practicability and convenience with the help of a smartphone. This work provides a promising approach for developing MOF-based ratiometric sensors to detect biomarkers.

A flexible polydentate Salamo-Salen-Salamo hybrid ligand H 4 L was designed and synthesized, which has rich pockets (salamo and salen pockets) so that it may have fascinating coordination patterns with transition metal(II) ions. Four multinuclear transition metal(II) complexes, novel butterfly-shaped homotetranuclear [Ni 4 (L)(μ 1 -OAc) 2 (μ 1,3 -OAc) 2 (H 2 O) 0.5 (CH 3 CH 2 OH) 3.5 ]·4CH 3 CH 2 OH ( 1 ), helical homotrinuclear [Zn 3 (L)(μ 1 -OAc) 2 ]·2CH 3 CH 2 OH ( 2 ), double-helical homotrinuclear [Cu 2 (H 2 L) 2 ]·2CH 3 CN ( 3 ), and mononuclear [Ni(H 2 L)]·1.5CH 3 COCH 3 ( 4 ), have been synthesized and characterized by single-crystal X-ray diffraction. The effects of different anions [OAc – and (O 2 C 5 H 7 ) 2– ] on the complexation behavior of H 4 L with transition metal(II) ions were studied by UV–vis spectrophotometry. The fluorescent properties of the four complexes were studied with zebrafish, which are expected to be a potential light-emitting material. Ultimately, interaction region indicator (IRI) valuations, Hirshfeld surface analyses, density functional theory…

The design of highly stable and dual-emission lanthanide metal–organic frameworks (Ln-MOFs) is promising for practical chemical sensor applications. Rational design and synthesis of photoresponsive organic ligands provide a feasible approach to achieving highly fluorescent dual-emission Ln-MOFs. In this study, a tetraphenylpyrazine-based AIE ligand, H 4 L, was synthesized and combined with lanthanide ions (including Sm 3+, Eu 3+, Gd 3+, and Tb 3+ ) to fabricate a series of Ln-MOFs named Ln-L. The single-crystal analysis revealed that all Ln-L belonged to the tetragonal space group P 42 1 2 and featured a 2-fold interpenetrated 3D structure. Leveraging rational design, Eu-L exhibited a sensitive response to tetracycline, making it a promising fluorescence sensor for tetracycline detection. The experiments demonstrated that Eu-L could rapidly and quantitatively detect tetracycline and its analogs within 30 s. The lowest detection limits for tetracycline, oxytetracycline, and chlortetracycline were 0.43, 0.92, and 0.81 μM, respectively. Additionally, the probe displayed excellent…

As a promising cost-effective nanozyme, MoS 2 nanosheets (NSs) have been considered as a good candidate for the enzyme-like catalysis. However, their catalytic activity is still restricted by the insufficient active sites and poor conductivity, and thus, the comprehensive performances are still unsatisfactory. To address these issues, herein, we design and fabricate an intelligent tubular nanostructure of hierarchical hollow nanotubes, which are assembled by NiS x /MoS 2 NSs encapsulated into N-doped carbon microtubes (NiS x /MoS 2 @NCMTs). The N-doped carbon microtubes (NCMTs) serve as a conductive skeleton, integrating with NiS x /MoS 2 NSs and ensuring their well-distribution, thereby maximally exposing more active sites. Additionally, the tube-like structure is favorable for increasing the mass transfusion to ensure their excellent catalytic performance. Profiting from their component and structural advantages, the obtained NiS x /MoS 2 @NCMTs exhibit a surprisingly enhanced enzyme-like activity. Based on these, a facile colorimetric sensing platform to detect H 2 O 2 and GSH…

Thermal quenching (TQ) is still a critical challenge for lanthanide (Ln 3+ )-doped luminescent materials. Herein, we report the novel negative thermal expansion nonhygroscopic phosphor ZrSc(WO 4 ) 2 PO 4:Yb 3+ /Er 3+ . Upon excitation with a 980 nm laser, a simultaneous thermal enhancement is realized on upconversion (UC) and downshifting (DS) emissions from room temperature to 573 K. In situ temperature-dependent X-ray diffraction and photoluminescence dynamics are used to reveal the luminescence mechanism in detail. The coexistence of the high energy transfer efficiency and the promoted radiative transition probability can be responsible for the thermally enhanced luminescence. On the basis of the luminescence intensity ratio of thermally coupled energy levels 2 H 11/2 and 4 S 3/2 at different temperatures, the relative and absolute sensitivities of the targeted samples reach 1.10% K –1 and 1.21% K –1, respectively, and the low-temperature uncertainty is approximately 0.1–0.4 K on the whole temperature with a high repeatability (98%). Our findings highlight a general approach for…

Rational design of fast and sensitive determination of nitrite (NO 2 – ) from a complicated actual sample overtakes a crucial role in constructing a high-efficiency sensing platform. Herein, a visual NO 2 – sensing platform with outstanding selectivity, sensitivity, and stability based on a surface plasmon resonance (SPR)-enhanced oxidase-like activity has been proposed. Benefiting from the intrinsic photocatalytic activity and limited light penetration of ZnS, the oxidase-like activity based on ZnS decorated on Ag nanowires (Ag@ZnS) is determined. It is demonstrated that the electrons are generated efficiently on the surface of ZnS and then transferred into the hot electrons of Ag with the help of localized SPR excitation, thus greatly oxidating the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to produce dark blue oxidized TMB (oxTMB). When nitrite is added into the reaction system, the oxTMB will selectively react with NO 2 – to generate diazotized oxTMB, leading to a visual color change from dark blue to light green and subsequently to dark yellow. Owing to the specific…

Planar Ni(II) porphyrinoid complexes have been widely used in electrochemical carbon dioxide reduction reaction and oxygen reduction reaction as well as hydrogen evolution reaction (HER). However, nonplanar Ni(II) tetra-pyrrolic complexes have not been thoroughly investigated thus far. In this study, three highly bent bis(dipyrrin) Ni(II) complexes have been synthesized to investigate their structure, electronic property, and electrocatalytic HER activities. Cyclic voltammetry and thin-layer UV–visible spectroelectrochemistry studies revealed four redox processes, yielding two reduced species as the final products. The i c / i p values of phenyl- and pentafluorophenyl-bearing bis(dipyrrin) Ni(II) complexes were >30 when trifluoroacetic acid was used as the proton source, and their Faradaic efficiencies for H 2 generation were >93%. Density functional theory calculations of the HERs revealed low endothermic energies of bent bis(dipyrrin) Ni(II) complexes.

The purification of natural gas and the removal of carbon dioxide from flue gases are crucial to economize precious resources and effectively relieve a series of environmental problems caused by global warming. Metal–organic framework (MOF) materials have demonstrated remarkable performance and benefits in the area of gas separation; however, obtaining materials with high gas capacity and selectivity simultaneously remains difficult. In addition, harsh synthesis conditions and solvent toxicity have been restricted in large-scale production and industrial application. Therefore, MOF-801(Zr/Ce/Hf) was created based on the green synthesis of the MOF-801 construction unit by altering the kinds of metal salts, and the impact of three metal nodes on the performance of gas adsorption and separation was demonstrated by contrasting the three MOFs. The results showed that MOF-801(Ce) has the best CO 2 adsorption capacity (3.3 mmol/g at 298 K), which also was demonstrated with in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results, CO 2 /CH 4 (ideal adsorbed…

Fe 3+ -doped near-infrared (NIR) phosphors have received a lot of interest because they are nontoxic, inexpensive, and ecologically benign. In this work, Fe 3+ -activated Li 2 ZnAO 4 (A = Si, Ge) phosphors were synthesized by solid-phase reactions, in which Fe 3+ entered the Zn 2+ tetrahedral site. When excited by 300 nm UV light, broad NIR emission bands at 750 nm (Li 2 ZnSiO 4: Fe 3+ ) and 777 nm (Li 2 ZnGeO 4: Fe 3+ ) were observed, with internal quantum efficiencies (IQE) of 62.70% (Li 2 ZnSiO 4: Fe 3+ ) and 30.57% (Li 2 ZnGeO 4: Fe 3+ ). The thermal stability was increased from 35.43 to 49.79% at 373 K via cationic regulation. The combination of activation energy, electron–phonon coupling, and Debye temperature explained the improved thermal stability of Li 2 ZnGeO 4: Fe 3+ phosphor. Besides, the as-synthesized phosphor demonstrated sensitive and selective Cu 2+ ion detection.

Photocatalytic water splitting into H2 is the most economic and environmentally friendly strategy for H2 production, and rationally constructing a heterojunction retains enormous influence on a photocatalytic system. Herein, 2D/2D covalent organic framework/graphitic carbon nitride (COF/CN) van der Waals heterojunctions were readily prepared via an ultrasonic method for high-efficiency visible-light photocatalytic H2 production. The photocatalytic H2 production performance of optimized COF/CN composites can reach up to 449.64 μmol·h–1, which is approximately 5 times that of pure CN (89.08 μmol·h–1). The characterization and experimental studies reveal that the synergistic effect between COF and CN contributes to promoting the interfacial migration and spatial separation of photoinduced e––h+ pairs, further boosting the photocatalytic hydrogen production activity. This work may open a new window to design and fabricate effective heterojunction photocatalysts for photocatalytic energy conversion.

Formaldehyde (HCHO) is a hazardous pollutant in indoor space for humans because of its carcinogenicity. Removing the pollutant by MnO 2 -based catalysts is of great interest because of their high oxidation performance at room temperature. In this work, we regulate the Pt–MnO 2 (MnO 2 = manganese oxide) interaction and interface by embedding Pt in MnO 2 (Pt-in-MnO 2 ) and by dispersing Pt on MnO 2 (Pt-on-MnO 2 ) for HCHO oxidation over Pt–MnO 2 catalysts with trace Pt loading of 0.01 wt %. In comparison to the Pt-in-MnO 2 catalyst, the Pt-on-MnO 2 catalyst has a higher Brunauer–Emmett–Teller surface area, a more active lattice oxygen, more oxygen vacancy activating more dioxygen molecules, more exposed Pt atoms, and noninternal diffusion of mass transfer, which contribute to the higher HCHO oxidation performance. The HCHO oxidation performance is stable over the Pt–MnO 2 catalysts under high space velocity and high moisture humidity conditions, showing great potential for practical applications. This work demonstrates a more effective Pt-dispersed MnO 2 catalyst than Pt-embedded MnO…

High Resolution Image Download MS PowerPoint Slide A 0.25% iron (Fe 3+ )-doped LiGaO 2 phosphor was synthesized by a high-temperature solid-state reaction method. The phosphor was characterized utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), high-pressure photoluminescence, and photoluminescence decay measurement techniques using diamond anvil cells (DACs). The powder X-ray analysis shows that the phosphor is a β polymorph of LiGaO 2 with an orthorhombic crystallographic structure at room temperature. The SEM result also confirms the presence of well-dispersed micro-rod-like structures throughout the sample. The photoluminescence studies in the near-infrared (NIR) range were performed at ambient, low-temperature, and high-pressure conditions. The synthesized phosphor exhibits a photoluminescence band around 746 nm related to the 4 T 1 → 6 A 1 transition with a 28% quantum efficiency at ambient conditions, which shifts toward longer wavelengths with the increase of pressure. The excitation spectra of Fe 3+ are very well fitted with the Tanabe–Sugano…

Electrocatalytic reduction of NO to NH 3 (NORR) emerges as a promising route for achieving harmful NO treatment and sustainable NH 3 generation. In this work, we first report that Mo 2 C is an active and selective NORR catalyst. The developed Mo 2 C nanosheets deliver a high NH 3 yield rate of 122.7 μmol h –1 cm –2 with an NH 3 Faradaic efficiency of 86.3% at −0.4 V. Theoretical computations unveil that the surface-terminated Mo atoms on Mo 2 C can effectively activate NO, promote protonation energetics, and suppress proton adsorption, resulting in high NORR activity and selectivity of Mo 2 C.

The cyclo[18]carbon (C 18 ) has piqued widespread interest in recent years for its geometrical aesthetic and unique electronic structure. Inspired by it, theoretical investigations of its isoelectronic B 9 N 9 have been published occasionally; however, few studies considered their other companion B 6 C 6 N 6 . In this work, we study the geometric structure, charge distribution, bonding characteristic, aromaticity, and electron delocalization of B 6 C 6 N 6 and B 9 N 9 for the first time and compare the relevant results with those of C 18 . Based on the comprehensive analysis of aromaticity indicators such as AV1245, nucleus-independent chemical shifts, anisotropy of the induced current density, magnetically induced current density, iso-chemical shielding surface, and induced magnetic field ( B ind ), we found that B 6 C 6 N 6 has definitely a double aromatic character similar to C 18 and the aromaticities of the two are very close, while B 9 N 9 is a nonaromatic species. In response to this novel finding, we delved into its nature from an electron delocalization perspective through…

Seawater electrolysis driven by renewable electricity is deemed a promising and sustainable strategy for green hydrogen production, but it is still formidably challenging. Here, we report an iron-doped NiS nanosheet array on Ni foam (Fe–NiS/NF) as a high-performance and stable seawater splitting electrocatalyst. Such Fe–NiS/NF catalyst needs overpotentials of only 420 and 270 mV at 1000 mA cm –2 for the oxygen evolution reaction and hydrogen evolution reaction in alkaline seawater, respectively. Furthermore, its two-electrode electrolyzer needs a cell voltage of 1.88 V for 1000 mA cm –2 with 50 h of long-term electrochemical durability in alkaline seawater. Additionally, in situ electrochemical Raman and infrared spectroscopy were employed to detect the reconstitution process of NiOOH and the generation of oxygen intermediates under reaction conditions.

Designing of a visible-light-driven semiconductor-based heterojunction with suitable band alignment and well-defined interfacial contact is considered to be an effective strategy for the transformation of solar-to-chemical energy and environmental remediation. In this context, MXenes have received tremendous attention in the research community due to their merits of abundant derivatives, elemental composition, excellent metallic conductivity, and surface termination groups. Meanwhile, a facile synthetic strategy for MXene-derived TiO 2 nanocomposites with stable framework and higher photocatalytic activity under visible-light irradiation still remains a challenge for researchers. Herein, we report a novel synthetic strategy of preparing a two-dimensional Ti 3 C 2 @TiO 2 nanohybrid by a facile reflux method under acidic conditions. In this oxidation reaction, protonation of the hydroxyl terminal group of MXene creates Ti more electrophilic and susceptible to an oxidative nucleophilic addition reaction with the presence of both water and oxygen. The physicochemical properties of the…

, Fe-MOF) decorated with platinum nanoparticles (Pt NPs), was prepared first and exhibited remarkably improved and excellent peroxidase-mimicking activity compared to the Fe-MOF material resulting from the synergistic catalysis effect between Fe-MOF and Pt NPs, which can effectively catalyze 3,3',5,5'-tetramethylbenzidine (TMB) oxidation to generate a blue product (oxidized TMB, oxTMB). Interestingly, in the presence of AChE and acetylcholinesterase, the peroxidase-mimicking activity from Pt NPs/Fe-MOF was inhibited obviously, and thus, a colorimetric sensing platform for AChE can be constructed; more importantly, after the addition of OPs, this nanozyme activity can be recovered, inducing the further successful construction of a sensitive colorimetric sensing platform for OPs. The related sensing mechanism and condition optimization were studied, and the as-prepared Pt NPs/Fe-MOF nanozyme-based colorimetric method for AChE and OP detection displayed superior analytical performances with wide linearities and low detection limits. Furthermore, the designed method offers satisfactory…

Carbon dioxide cycloaddition into fine chemicals is prospective technology to solve energy crisis and environmental issues. However, high temperature and pressure are usually required in the conventional cycloaddition reactions of CO 2 with epoxides. Moreover, metal active sites play a vital role in the CO 2 cycloaddition, but it is still unclear. Herein, we select the isostructural MOF-919-Cu-Fe and MOF-919-Cu-Al as models to promote the performance and clarify the effects of metal type on the CO 2 cycloaddition. The MOF-919-Cu-Fe with exposed Fe and Cu Lewis acid sites reaches the CO 2 cycloaddition with over 99.9% conversion and over 99.9% selectivity at room temperature and a 1 bar CO 2 atmosphere, 3.0- and 52.6-fold higher than those of the MOF-919-Cu-Al with Al and Cu sites (33.8%) and the 1H-pyrazole-4-carboxylic acid, Fe, and Cu mixed system (1.9%), respectively. The proposed mechanism demonstrated that the exposed Fe 3+ sites facilitate the ring opening of epoxide and CO 2 activation to boost the CO 2 cycloaddition reaction. This work provides a new insight to tune the…

Water electrolysis is considered as one of the alternative potential approaches for producing renewable energy. Due to the sluggish kinetic nature of oxygen evolution reaction (OER), it encounters a significant overpotential to achieve water electrolysis. Hence, the advancement of cost-effective transition metal-based catalysts toward water splitting has gained global attention in recent years. In this work, the doping of Fe over amorphous NiWO 4 increased the OER activity effectively and achieved stable oxygen evolution in the alkaline medium, which show better electrocatalytic activity as compared to crystalline tungstate. As NiWO 4 has poor activity toward OER in the alkaline medium, the doping of Fe 3+ will tune the electronic structure of Ni in NiWO 4 and boost the OER activity. The as-synthesized Fe-doped amorphous NiWO 4 exhibits a low overpotential of 230 mV to achieve a current density of 10 mA cm –2 and a lower Tafel slope value of 48 mV dec –1 toward OER in 1.0 M KOH solution. The catalyst also exhibits long-term static stability of 30 h during chronoamperometric study.…

Urea oxidation reaction (UOR), with a low thermodynamic potential, offers great promise for replacing anodic oxygen evolution reaction of electrolysis systems such as water splitting, carbon dioxide reduction, etc., thus reducing the overall energy consumption. To promote the sluggish kinetics of UOR, highly efficient electrocatalysts are required, and Ni-based materials have been widely investigated. However, most of these reported Ni-based catalysts suffer from large overpotentials, as they generally undergo self-oxidation to form NiOOH species at high potentials, which act as catalytically active sites for UOR. Herein, Ni-doped MnO 2 (Ni-MnO 2 ) nanosheet arrays were successfully prepared on nickel foam. The as-fabricated Ni-MnO 2 shows distinct UOR behavior with most of the previously reported Ni-based catalysts, as urea oxidation on Ni-MnO 2 proceeds before the formation of NiOOH. Notably, a low potential of 1.388 V vs reversible hydrogen electrode was required to achieve a high current density of 100 mA cm –2 on Ni-MnO 2 . It is suggested that both Ni doping and nanosheet…

The construction of metal–organic cages (MOCs) with specific structures and fluorescence sensing properties is of much importance and challenging. Herein, a novel phenanthroline-based metal–organic cage, [Cd 3 L 3 ·6MeOH·6H 2 O] ( 1 ), was synthesized by metal-directed assembly of the ligand 3,3′-[(1 E,1′ E )-(1,10-phenanthroline-2,9-diyl)bis(ethene-2,1-diyl)]dibenzoic acid ( H 2 L ) and CdI 2 using a solvothermal method. According to single-crystal X-ray analysis, cage 1 exhibits a rare trefoil-shaped structure. Meanwhile, the discrete MOCs are further stacked into a 3D porous supramolecular structure through abundant intermolecular C–H···O interactions. Additionally, through exploration of fluorescence sensing on cations, anions, and antibiotics in aqueous solution, the experimental results indicate that cage 1 has excellent fluorescence sensing abilities for Fe 3+, Cr 2 O 7 2–, and nitrofuran and nitroimidazole antibiotics. The sensing ability of 1 remains unaltered for five cycles toward all analytes. The above results suggested that cage 1 can be considered a potential multiple…

Ternary Pt-based structures are a positive progress in addressing the disadvantages of monometallic and bimetallic Pt-based alloys for the electrochemical oxidation process of simple alcohols, which is a vital half-reaction in fuel cell technologies. We herein report a facile NaBH 4 -assisted ethylene glycol reduction process for fabricating a series of nanosized PtRuNi ternary alloys to explore the relationship between physicochemical properties and electrocatalytic behaviors for the acidic methanol oxidation reaction (MOR). Owing to a balance between lattice strain and synergistic effects, the Pt 60 Ru 20 Ni 20 /C electrocatalyst shows the highest MOR efficiency with the mass activity/specific activity of 844.48 mA mg Metal –1 /1.93 mA cm –2, being a 1.94 and 2.38 times increase compared to those of the PtRu catalyst, respectively. Also, the Pt 60 Ru 20 Ni 20 /C catalyst possesses superior CO-tolerance and durability in strongly acidic electrolytes. This work suggests that optimizing the surface strain and electronic effects can boost the overall MOR efficiency of multicomponent…

High Resolution Image Download MS PowerPoint Slide Eight rhenium(I) tricarbonyl aqua complexes with the general formula fac -[Re(CO) 3 ( N,N ′-bid)(H 2 O)][NO 3 ] ( 1–8 ), where N,N ′-bid is (2,6-dimethoxypyridyl)imidazo[4,5- f ]1,10-phenanthroline ( L1 ), (indole)imidazo[4,5- f ]1,10-phenanthroline ( L2 ), (5-methoxyindole)-imidazo[4,5- f ]1,10-phenanthroline ( L3 ), (biphenyl)imidazo[4,5- f ]1,10-phenanthroline ( L4 ), (fluorene)imidazo[4,5- f ]1,10-phenanthroline ( L5 ), (benzo[ b ]thiophene)imidazo[4,5- f ]1,10-phenanthroline ( L6 ), (5-bromothiazole)imidazo[4,5- f ]1,10-phenanthroline ( L7 ), and (4,5-dimethylthiophene)imidazo[4,5- f ]1,10-phenanthroline ( L8 ), were synthesized and characterized using 1 H and 13 C{ 1 H} NMR, FT-IR, UV/Vis absorption spectroscopy, and ESI-mass spectrometry, and their purity was confirmed by elemental analysis. The stability of the complexes in aqueous buffer solution (pH 7.4) was confirmed by UV/Vis spectroscopy. The cytotoxicity of the complexes ( 1–8 ) was then evaluated on prostate cancer cells (PC3), showing a low nanomolar to low…

Half-sandwich Ru(II) complexes containing nitro-substituted furoylthiourea ligands, bearing the general formula [( η 6 - p -cymene)RuCl 2 (L)] ( 1 – 6 ) and [( η 6 - p -cymene)RuCl(L)(PPh 3 )] + ( 7– - 12 ), have been synthesized and characterized. In contrast to the spectroscopic data which revealed monodentate coordination of the ligands to the Ru(II) ion via a “S” atom, single crystal X-ray structures revealed an unusual bidentate N, S coordination with the metal center forming a four-membered ring. Interaction studies by absorption, emission, and viscosity measurements revealed intercalation of the Ru(II) complexes with calf thymus (CT) DNA. The complexes showed good interactions with bovine serum albumin (BSA) as well. Further, their cytotoxicity was explored exclusively against breast cancer cells, namely, MCF-7, T47-D, and MDA-MB-231, wherein all of the complexes were found to display more pronounced activity than their ligand counterparts. Complexes 7 – 12 bearing triphenylphosphine displayed significant cytotoxicity, among which complex 12 showed IC 50 values of 0.6 ± 0.9,…

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs), as a new generation of NIR lighting sources, have wide prospects in the areas of food analysis and biological and night vision imaging. Nevertheless, NIR phosphors are still limited by short-wave and narrowband emissions as well as low efficiency. Herein, a series of NIR phosphors, LuCa 2 ScZrGa 2 GeO 12:Cr 3+ (LCSZGG:Cr 3+ ), with broadband emissions have been developed and first reported. At 456 nm excitation, the optimized LCSZGG:0.005Cr 3+ phosphor represents an ultra-broadband emission within the range of 650–1100 nm, peaking near 815 nm with a full width at half maximum of 166 nm. Furthermore, the LCSZGG:0.005Cr 3+ phosphor possesses good internal quantum efficiency of 68.75%, and its integrated emission intensity at 423 K still retains about 64.17% of that at room temperature. By combining the optimized sample with a blue chip, a NIR pc-LED device is fabricated, which has an excellent NIR output power of 37.88 mW with an NIR photoelectric conversion efficiency of 12.44% under a 100 mA driving current. The…

Photoelectrochemical nitrate reduction reaction (PEC NIRR) could convert the harmful pollutant nitrate (NO 3 – ) to high-value-added ammonia (NH 3 ) under mild conditions. However, the catalysts are currently hindered by the low catalytic activity and slow kinetics. Here, we reported a heterostructure composed of CeO 2 and BiVO 4, and the “frustrated Lewis pairs (FLPs)” concept was introduced for understanding the role of Lewis acids and Lewis bases on PEC NIRR. The electron density difference maps indicated that FLPs were significantly active for the adsorption and activation of NO 3 – . Furthermore, carbon (C) improved the carrier transport ability and kinetics, contributing to the NH 3 yield of 21.81 μg h –1 cm –2 . The conversion process of NO 3 – to NH 3 was tracked by 15 NO 3 – and 14 NO 3 – isotopic labeling. Therefore, this study demonstrated the potential of CeO 2 –C/BiVO 4 for efficient PEC NIRR and provided a unique mechanism for the adsorption and activation of NO 3 – over FLPs.

Quinolone antibiotic residues, norfloxacin (NORF) and ciprofloxacin (CIP), have attracted more attention due to their frequent detection in surface water and food field, which seriously threaten the health of animals and humans. Rapid and efficient detection of NORF and CIP is critical for environmental testing and ecosystems. Herein, two novel isostructural viologen-functionalized Ln(III) complexes [Ln 2 L 0.5 (IPA) 3 ] n (Ln = Eu, 1; Tb, 2; L = N, N ′-bis (2-carboxyethyl)-4,4′-bipyridridylium dichloride, H 2 IPA = isophthalic acid) with a three-dimensional structure have been synthesized solvothermally. Complexes 1 and 2 exhibited reversible photochromism under UV light. In addition, complex 1 exhibits excellent pH tolerance and can be seen as an efficient fluorescent probe for the detection of NORF and CIP with detection limits of 7.90 × 10 –7 and 9.48 × 10 –7 M, respectively. Furthermore, the good photoresponsive and outstanding fluorescent properties of 1 were further exploited in dual-function paper involving erasable inkless printing and detection of NORF and CIP. Our work…

A novel cobalt hydrogen-bonded organic framework (Co-HOF, C 24 H 14 CoN 4 O 8 ) was synthesized from a mixed linker, that is, 2,5-pyridinedicarboxylic acid (PDC) and 2,2′-bipyridyl (BPY) linkers and cobalt ion through a simple, one-pot, low-cost, and scalable solvothermal method. The Co-HOF was fully characterized using several analytical and spectroscopic techniques including single-crystal X-ray diffraction, diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy. The Co-HOF exhibits high thermal and chemical stabilities compared to previously reported HOF materials. Moreover, Co-HOF shows excellent photocatalytic activity under visible light irradiation due to its narrow band gap of 2.05 eV. The cycloaddition reaction of CO 2 to variable epoxides was investigated to evaluate the photocatalytic performance of Co-HOF under visible light radiation and was found to produce the corresponding cyclic carbonates in yields up to 99.9%.

Near-infrared (NIR) phosphor-converted light-emitting diodes with broadband emission have received considerable interest. However, there remains a challenge in the construction of ultra-broadband NIR phosphors, hindering their further application. In this work, a heterovalent substitution strategy is proposed to construct a novel ultra-broadband NIR-emitting LaTiTaO 6:Cr 3+ phosphor with a full width at half maximum of ∼300 nm. Crystal structure, time-resolved emission spectroscopy, and electron paramagnetic resonance analyses confirm that only one crystallographic site of Cr 3+ with separated ions exists. Electron and phonon coupling (EPC) evaluated by the Huang–Rhys factor ( S ) reveals that the heterovalent substitution strategy contributes to strong EPC with S = 9.185, resulting in ultra-broadband emission. Interestingly, a remarkable blue shift of emission from 1050 to 922 nm with increasing temperature is observed. Moreover, the application of LaTiTaO 6:Cr 3+ phosphor is demonstrated in the qualitative analysis of ethanol/water mixtures. The work will enrich the toolbox for…

Metal–organic frameworks (MOFs) have been recognized as one of the most promising porous materials and offer great opportunities for the rational design of new catalytic solids having great structural diversity and functional tunability. Despite numerous inherent merits, their chemical environment instability limits their practical usage and demands further exploration. Herein, by employing the mixed-ligand approach, we have designed and developed a robust 3D Co-MOF, [Co 2 (μ 2 -O)(TDC) 2 (L)(H 2 O) 2 ]·2DMF (H 2 TDC = 2,5-thiophenedicarboxylic acid, L = 3,3′-azobispyridine), IITKGP-50 (IITKGP stands for the Indian Institute of Technology Kharagpur), which exhibited excellent framework robustness not only in water but also in a wide range of aqueous pH solutions (pH = 2–12). Taking advantage of superior framework robustness and the presence of high-density open metal sites, IITKGP-50 was further explored in catalyzing the two-component Knoevenagel condensation reaction and three-component Strecker reactions. Moreover, to verify the size selectivity of IITKGP-50, smaller to bulkier…

An aqueous stable europium-based metal–organic framework with properties of ratiometric fluorescence sensing, namely, {[(CH 3 ) 2 NH 2 ][Eu(TCPB)(H 2 O) 2 ]·DMF} n ( Eu-MOF; H 4 TCPB = 1,2,4,5-tetrakis(4-carboxyphenyl)-benzene), was synthesized under solvothermal conditions and structurally characterized. Crystal structure analysis shows that Eu-MOF is a three-dimensional porous crystal, in which the Eu III ion is an eight-coordinate square inverse prism with eight oxygen atoms. Fluorescence measurements show that Eu-MOF exhibits characteristic emission of the Eu III ion and ligand. Eu-MOF displays good selectivity and sensitivity as a ratiometric fluorescence sensor for phosphate anions with a low detection limit in Tris–HCl buffer solution. Furthermore, Eu-MOF also has a good ability to identify salicylaldehyde through fluorescence quenching with a detection limit of 0.095 ppm. Therefore, it is an excellent fluorescent sensing material for phosphate and organic salicylaldehyde.

The S-scheme heterojunction photocatalyst holds potential for better photocatalysis owing to its capacity to broaden the light absorption range, ease electron–hole separation, extend the charge carrier lifespan, and maximize the redox ability. In this study, we integrate zeolitic imidazolate frameworks (ZIFs-67) with the CuFe-LDH composite, offering a straightforward approach towards creating a novel hybrid nanostructure, enabling remarkable performance in both photocatalytic hydrogen (H 2 ) evolution and carbon dioxide (CO 2 ) to methanol (MeOH) conversion. The ZIF-67/CuFe-LDH photocatalyst exhibits an enhanced photocatalytic hydrogen evolution rate of 7.4 mmol g –1 h –1 and an AQY of 4.8%. The superior activity of CO 2 reduction to MeOH generation was 227 μmol g –1 h –1 and an AQY of 5.1%, and it still exhibited superior activity after continuously working for 4 runs with nearly negligible decay in activity. The combined spectroscopic analysis, electrochemical study, and computational data strongly demonstrate that this hybrid material integrates the advantageous properties of the…

The electrochemical nitrate reduction reaction (NO 3 RR) is an attractive green alternative to the conventional Haber–Bosch method for the synthesis of NH 3 . However, this reaction is a tandem process that involves multiple steps of electrons and protons, posing a significant challenge to the efficient synthesis of NH 3 . Herein, we report a high-rate NO 3 RR electrocatalyst of Fe and Cu double-doped Co 3 O 4 nanorod (Fe 1 /Cu 2 -Co 3 O 4 ) with abundant oxygen vacancies, where the Cu preferentially catalyzes the rapid conversion of NO 3 – to NO 2 – and the oxygen vacancy in the Co 3 O 4 substrate can accelerate NO 2 – reduction to NH 3 . In addition, the introduction of Fe can efficiently capture atomic H* that promotes the dynamics of NO 2 – to NH 3, improving Faradaic efficiency of the produced NH 3 . Controlled experimental results show that the optimal electrocatalyst of Fe 1 /Cu 2 -Co 3 O 4 exhibits good performance with high conversion (93.39%), Faradaic efficiency (98.15%), and ammonia selectivity (98.19%), which is significantly better than other Co-based materials. This…

High Resolution Image Download MS PowerPoint Slide Two-dimensional hybrid-organic–inorganic perovskite (2D-HOIP) lead bromide perovskite crystals have demonstrated great potential as scintillators with high light yields and fast decay times while also being low cost with solution-processable materials for wide energy radiation detection. Ion doping has been also shown to be a very promising avenue for improvements of the scintillation properties of 2D-HOIP crystals. In this paper, we discuss the effect of rubidium (Rb) doping on two previously reported 2D-HOIP single crystals, BA 2 PbBr 4 and PEA 2 PbBr 4 . We observe that doping the perovskite crystals with Rb ions leads to an expansion of the crystal lattices of the materials, which also leads to narrowing of band gaps down to 84% of the pure compounds. Rb doping of BA 2 PbBr 4 and PEA 2 PbBr 4 shows a broadening in the photoluminescence and scintillation emissions of both perovskite crystals. Rb doping also leads to faster γ-ray scintillation decay times, as fast as 4.4 ns, with average decay time decreases of 15% and 8% for…

High Resolution Image Download MS PowerPoint Slide We report the synthesis and characterization of three novel Schiff bases ( L1 – L3 ) derived from the condensation of 2-carbaldehyde-8-hydroxyquinoline with amines containing morpholine or piperidine moieties. These were reacted with CuCl 2 and ZnCl 2 yielding six new coordination compounds, with the general formula ML 2, where M = Cu(II) or Zn(II) and L = L1 – L3, which were all characterized by analytical, spectroscopic (Fourier transform infrared (FTIR), UV–visible absorption, nuclear magnetic resonance (NMR), or electron paramagnetic resonance (EPR)), and mass spectrometric techniques, as well as by single-crystal X-ray diffraction. In the solid state, two Cu(II) complexes, with L1 and L2, are obtained as dinuclear compounds, with relatively short Cu–Cu distances (3.146 and 3.171 Å for Cu 2 (L1) 4 and Cu 2 (L2) 4, respectively). The free ligands show moderate lipophilicity, while their complexes are more lipophilic. The p K a values of L1 – L3 and formation constants of the complex (for ML and ML 2 ) species were determined by…

Two novel lanthanide metal–organic frameworks (MOFs) with the formulas [Tb(bidc)(Hbidc)(H 2 O)] n ( JXUST-20 ) and {[Tb 3 (bidc) 4 (HCOO)(DMF)]·solvents} n ( JXUST-21 ) were synthesized based on 2,1,3-benzothiadiazole-4,7-dicarboxylic acid (H 2 BTDC) under solvothermal conditions. Interestingly, benzimidazole-4,7-dicarboxylic acid (H 2 bidc) was formed in situ using H 2 BTDC as the starting material. The self-assembly process of the targeted MOFs with different topological structures can be controlled by the solvents and concentration of the reactants. Luminescence experiments show that JXUST-20 and JXUST-21 exhibit strong yellow-green emission. JXUST-20 and JXUST-21 can selectively sense benzaldehyde (BzH) via a luminescence quenching effect with detection limits of 15.3 and 1.44 ppm, respectively. In order to expand the practical application of MOF materials, mixed-matrix membranes (MMMs) have been constructed by mixing targeted MOFs and poly(methyl methacrylate) in a N, N -dimethylformamide (DMF) solution, which can also be used for BzH vapor sensing. Therefore, the first case of…

The development of a MOFs-derived multilevel hierarchy in a single step still remains a challenging task. Herein, we have synthesized novel Cu-MOF via a slow diffusion method at ambient temperature and further utilized it as a precursor source for MOF-derived multilevel hierarchy (Cu/Cu x O@NC, x = 1 and 2). This studies suggest that the organic ligands served as a source of an N-doped carbon matrix encapsulated with metal oxide nanoparticles which were confirmed by various characterization techniques; further BET analysis reveals a surface area of 178.46 m 2 /g. The synthesized multilevel hierarchy was utilized as an electro-active material in a supercapacitor that achieved a specific capacitance of 546.6 F g –1 at a current density of 1 A g –1 with a higher cyclic retention of 91.81% after 10 000 GCD cycles. Furthermore, the ASC device was fabricated using Cu/Cu x O@NC as the positive electrode and carbon black as the negative electrode and utilized to enlighten the commercially available LED bulb. The fabricated ASC device was further employed for a two-electrode study which…

A lanthanide-based molecular crystalline material endows metal–organic frameworks (MOFs) with many fascinating applications such as fluorescence detection and CO 2 chemical fixation. Herein, we describe and study a multipurpose europium(III) MOF with the formula of {[Eu 2 (TATAB) 2 ]·2.5H 2 O·2DMF} n ( Eu-MOF ) (where H 3 TATAB is 4,4′,4″-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tribenzoic acid ligand) for photoluminescence sensor matrix and CO 2 chemical fixation. This Eu-MOF features 1D square channels along the c direction with a pore size of ca.14.07 Å × 14.07 Å, occupied by lattice water and DMF molecules. The obtained Eu-MOF can achieve simultaneous luminescence of the H 3 TATAB ligand and Eu 3+ ions, which can be developed as the sensor matrix for ratiometric fluorescence thermometry. The luminescence of the Eu-MOF demonstrates an obvious color change from red to yellow as temperature rises from 303 to 373 K and the Eu-MOF has a satisfying relative sensitivity of 3.21% K –1 and a small temperature uncertainty of 0.0093 K at 333 K. Moreover, sensitive detection of gossypol…

From the environmental protection and human health perspectives, the design and synthesis of efficient and reusable oxidative desulfurization nanocatalysts has always been sought after by scientists and industries. In this regard, a new heterogeneous nanocatalyst (V-SPM@PANI@CH) was synthesized by immobilizing Keggin-type vanadium-substituted phosphomolybdate ([PVMo 11 O 39 ] 4– ) (named V-SPM) clusters on the surface of polyaniline (PANI) and chitosan (CH) polymers. The features of the assembled nanocatalyst were detected by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy techniques in detail. The XRD studies indicated that the average crystallite size of V-SPM@PANI@CH was estimated to be about 36 nm. The catalytic performance of V-SPM@PANI@CH was investigated in the extractive and catalytic oxidation desulfurization (ECOD) procedure of real and thiophenic model gasoline by H 2 O 2 /AcOH (volume proportion of 2:1) as an oxidizing system. The optimal…

Photochromic metal–organic complexes (PMOCs) have received huge attention of chemists, thanks to their diverse structural characteristic and various available photo-modulate physicochemical functionalities. The organic ligand plays a crucial role in the quest of PMOCs with specific photo-responsive functionalities. The multiple coordination modes of polydentate ligands also provide possibilities for forming isomeric MOCs, which may open a new perspective on the research of PMOCs. The exploration of suitable PMOC systems is significant for the yield of isomeric PMOCs. Taking into account extant PMOCs based on polypyridines and carboxylate as electron acceptors (EAs) and donors (EDs), the covalent fusion of suitable pyridyl and carboxyl species may produce single functionalized ligands bearing ED and EA moieties for the building of novel PMOCs. In this study, the coordination assembly of bipyridinedicarboxylate (2,2′-bipyridine-4,4′-dicarboxylic acid, H 2 bpdc) and Pb 2+ ions generate two isomeric MOCs, [Pb(bpdc)]·H 2 O ( 1 and 2 ), which have the same chemical compositions with main…

Electrochemical oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) is a promising approach to produce high-value chemicals such as 2,5-furandicarboxylic acid (FDCA). However, the undesirable stability of catalysts commonly limits its potential application value. In this work, NiOOH derived from Ni­(OH)2 was determined as the main catalytic site for HMF oxidation, but the collapse of Ni­(OH)2 caused severe instability during the electrocatalytic process because of the crystal structure mismatch between NiOOH and Ni­(OH)2. The implantation of Ce in Ni­(OH)2 (Ce-Ni­(OH)2) was successfully realized to address the stability issue of bare Ni­(OH)2, since the larger ion radius of Ce could increase the Ni–O bond length and d-spacing. As a result, the activity of 14%Ce-Ni­(OH)2 has not obviously decayed after the 50 cyclic voltammetry (CV)-cycle test. HMF conversion is close to 100%, and the Faraday efficiency (FE) reaches 86.6% at the potential of 0.45 V vs Ag/AgCl. This study provides a new strategy to design stable catalysts for the conversion of biomass derivatives.

A one-dimensional Cd(II) chain coordination polymer constructed by an electron-deficient viologen-anchored carboxylate ligand was successfully synthesized. Owing to the favorable stimuli-chromic properties of viologen, the title compound shows reversible photochromism, thermochromism, electrochromism, and naked-eye-detectable differentiable vapochromic response to different volatile amines. The chromic behaviors of it are ascribed to the formation of viologen radicals triggered by external stimuli. And the differentiated response to volatile amines is attributed to the size effect of the amines as well as the steric hindrance effect of forming α/β C v –H···N amines interactions of the viologen unit to further affect the occurrence of electron transfer. Such an all-in-one crystalline material might have more practical applications in photoelectric, erasable inkless printing, light printing, and volatile amine detection fields.

The development of multifunctional and durable electrocatalysts for hydrogen energy production via an energy-saving avenue is urgently desired. Urea electrolysis by substituting the oxygen evolution reaction (OER) with a more oxidizable urea oxidation reaction (UOR) has been widely used to realize energy-saving hydrogen production. Herein, metal–organic framework (MOF)-derived interface-engineered NiMoO 4 @NiFeP core–shell nanorods as electrocatalysts are constructed. Due to the integration of the advantages of the interface synergistic effect between the NiMoO 4 core and NiFeP shell, the as-fabricated NiMoO 4 @NiFeP electrocatalyst demonstrates remarkable electrocatalytic performance toward the hydrogen evolution reaction (HER), OER, and UOR. In the urea electrolysis system, an ultralow cell voltage of 1.30 V is needed to drive the current density of 10 mA cm –2, which is 140 mV lower than that of the conventional overall water splitting system. The cost-efficient and high-performance NiMoO 4 @NiFeP electrocatalyst paves the way to explore practical applications of energy-saving…

Exploiting an affordable, durable, and high-performance electrocatalyst for the oxygen evolution reaction (OER) under lower pH condition (acidic) is highly challengeable and much attractive toward the hydrogen-based energy technologies. A spinel CoCr 2 O 4 is observed as a potential noble-metal-free candidate for OER in alkaline medium. The presence of Cr further leads to electronic structure modulation of Co 3 O 4 and thereby greatly increases the corrosive resistance toward OER in acidic environment. Herein, a typical CoCr 2 O 4 with three different morphologies was synthesized for the very first time and employed as an electrocatalyst for OER in alkaline (1 M KOH) and acidic (0.5 M H 2 SO 4 ) medium. Moreover, different morphologies display a different intrinsic exposed active site and thereby display different electrocatalytic activities. Likewise, the CoCr 2 O 4 Mic (synthesized by the microwave heating method) displays a higher catalytic activity toward OER and delivers a low overpotential of 293 and 290 mV to attain 10 mA/cm 2 current density and smaller Tafel slope values of…

The detection of the major biomarker of Bacillus anthracis, 2,6-dipicolinic acid (DPA), has attracted great interest in recent years. In this work, mixed-lanthanide metal–organic frameworks (M’LnMOFs), Tb x Eu 1– x -cppa (cppa = 5-(5-carboxypyridin-3-yl)isophthalic acid), with different Tb/Eu ratios, were solvothermally synthesized. The results reveal that ratiometric fluorescent probe [Tb 0.533 Eu 0.467 -(Hcppa) 1.5 (H 2 O)(DMF)]·3H 2 O is water and acid–base stable and exhibits excellent sensitivity (LOD = 2.286 μM), high selectivity, and fast response (<2 min) for the detection of DPA. Due to the blocked energy transfer from Tb 3+ to Eu 3+ and the inner filter effect upon the addition of DPA, the fluorescent probe shows a distinct color change from orange-red to green. Furthermore, the visual detection of DPA was realized by identifying the RGB values of MOF-based agarose hydrogel films via a smartphone, highlighting the practical application of the fluorescent probe for DPA detection under aqueous solution conditions.

Throughout extensive research endeavors, SrTiO 3 has emerged as a promising photocatalytic material for utilizing solar energy and facilitating hydrogen production via water splitting. Yet, the pursuit of enhanced efficiency and amplified hydrogen generation has prompted researchers to delve into the realm of advanced doping strategies. In this work, using experimental characteristics and DFT calculations, we studied the effect of cobalt substitution on the structural, electronic, optical, and magnetic properties as well as the photocatalytic activity of SrTi 1– x Co x O 3−δ ( x = 0, 0.125, 0.25, 0.375, and 0.5) perovskites. The samples were successfully prepared by using the solid-state reaction method. Based on X-ray diffraction and the Rietveld refinement method, the elaborated samples were shown to preserve the absorption range up to the visible region. Moreover, the position of band edge levels after cobalt doping becomes more appropriate for water splitting. Our findings report that all cobalt-doped compounds exhibit good photocatalytic activities and could be used as suitable…

High Resolution Image Download MS PowerPoint Slide To pursue the design of in vivo stable chelating systems for radiometals, a concise and straightforward method toolbox was developed combining NMR, isothermal titration calorimetry (ITC), and europium time-resolved laser-induced fluorescence spectroscopy (Eu-TRLFS). For this purpose, the macropa chelator was chosen, and Lu 3+, La 3+, Pb 2+, Ra 2+, and Ba 2+ were chosen as radiopharmaceutically relevant metal ions. They differ in charge (2+ and 3+) and coordination properties (main group vs lanthanides). 1 H NMR was used to determine four p K a values (±0.15; carboxylate functions, 2.40 and 3.13; amino functions, 6.80 and 7.73). Eu-TRLFS was used to validate the exclusive existence of the 1:1 M n + /ligand complex in the chosen pH range at tracer level concentrations. ITC measurements were accomplished to determine the resulting stability constants of the desired complexes, with log K values ranging from 18.5 for the Pb-mcp complex to 7.3 for the Lu-mcp complex. Density-functional-theory-calculated structures nicely mirror the…

The utilization of carbon dioxide (CO 2 ) as a C1 source coupled with olefins, readily accessible feedstocks, offers dual advantages of mitigating atmospheric carbon dioxide and green synthesis of valuable chemicals. In this regard, herein we demonstrate the application of Fe(III)-anchored porphyrin-based covalent organic framework (P-COF) as a promising recyclable catalyst for one-step generation of cyclic carbonates (CCs), value-added commodity chemicals from olefins and CO 2, under mild atmospheric pressure conditions. Moreover, this one-pot synthesis was applied to transform various olefins (aliphatic and aromatic) into the corresponding CCs in good yield and selectivity. In addition, the Fe(III)@P-COF showed good recyclability and durability for multiple reuse cycles without losing its catalytic activity. Notably, this one-step synthesis strategy presents an eco-friendly, atom-economic alternative to the conventional two-step process requiring epoxides. This work represents a rare demonstration of porphyrin COF-catalyzed one-pot CC synthesis by utilizing readily available…

Detecting toxic amine and pesticide contamination in the environment is one of the most pressing issues for environmental sustainability. In this work, two 3D Ln-BINDI complexes [Ln = Eu (1), Sm (2); H 4 BINDI ( N, N ′-bis(5-isophthalic acid)-1,4,5,8-naphthalenediimide)] have been designed and synthesized. Crystal structure of [Eu 2 (BINDI) (NO 3 ) 2 (DMA) 4 ]·2DMA (complex 1 ) featuring the lvt topology was determined by X-ray single-crystal diffraction. A multi-functional ratiometric luminescence sensor benefitting from π-electron-deficient NDI moieties and f–f transition characteristics of lanthanide Eu 3+ ions for complex 1 has been investigated. Markedly, complex 1 exhibit completely different selective fluorescence ratiometric turn-on responses and pretty high sensitivity behaviors to aromatic amines (OPD), aliphatic amines ( n -BA), and pesticides (TBZ), respectively, which are driven by interactions between the electron-donating amino group and acceptor NDI site, contributing to complex 1 as a potential ratiometric luminescent turn-on sensor for practical environmental…

Herein, hexaazamacrocyclic ligand L N6 was employed to construct a series of photochromic rare-earth complexes, [Ln(L N6 )(NO 3 ) 2 ](BPh 4 ) [ 1-Ln, Ln = Dy, Tb, Eu, Gd, Y; L N6 = (3 E,5 E,10 E,12 E )-3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane-3,5,10,12-tetraene]. The behavior of photogenerated radicals of hexaazamacrocyclic ligands was revealed for the first time. Upon 365 nm light irradiation, complexes 1-Ln exhibit photochromic behavior induced by photogenerated radicals according to EPR and UV–vis analyses. Static and dynamic magnetic studies of 1-Dy and irradiated product 1-Dy * indicate weak ferromagnetic interactions among Dy III ions and photogenerated L N6 radicals, as well as slow magnetization relaxation behavior under a 2 kOe applied field. Further fitting analyses show that the magnetization relaxation in 1-Dy * is markedly different from 1-Dy . Time-dependent fluorescence measurements reveal the characteristic luminescence quenching dynamics of lanthanide in the photochromic process. Especially for irradiated product 1-Eu *, the luminescence is almost…

A luminescent Tb-MOF with excellent stability and dual-emitting properties was constructed with an amide-functionalized tetracarboxylate ligand. Tb-MOF s were initially assembled on one-dimensional Tb 3+ chains, then formed a two-dimensional double–decker layer through the synergistic linking of organic ligands and bridging formic acid anions, and further fabricated the final three-dimensional structure through the connection of the organic ligands. Powder X-ray diffraction experiments revealed that Tb-MOF s not only exhibited excellent stability in water but also maintained structural integrity in the pH range of 2–12. Importantly, this Tb-MOF provided the first example of a metal–organic framework (MOF)-based luminescence sensor that can simultaneously detect two acid amino acids (aspartic and glutamic acids) through a turn-off sensing mechanism and two basic amino acids (lysine and arginine acids) through unusual turn-on and turn-off-on sensing mechanisms. Moreover, high sensitivity, low detection limit, and excellent recyclability of this sensor endow Tb-MOF s with great…

Electrochemical glucose oxidation reaction (GOR) is a promising alternative anodic reaction to water oxidation reaction for various electrochemical oxidation reactions owing to the relatively low thermodynamic potential of GOR and the abundant source of glucose from biomass-based platform molecules. However, it remains difficult to develop high-activity and low-cost electrocatalysts toward GOR. Herein, we report a NiCoSe x nanoplate supported on Ni foam with excellent activity for GOR electrocatalysis, which achieves a high current density of 500 mA cm –2 at 1.41 V vs reversible hydrogen electrode (RHE) and a 70.2% Faraday efficiency of formate at 1.40 V vs RHE. The surface component evolution of NiCoSe x is studied by an in situ Raman spectrum, which points out the catalytic active species to be CoO x /CoOOH and NiOOH. Furthermore, we develop a two-electrode cell by pairing GOR with hydrogen evolution reaction using the NiCoSe x electrode as the bifunctional catalyst for the anode and the cathode, which only requires an applied voltage of 1.50 V to reach a high current density of…

Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ) (NFPP) is an attractive candidate for Na + batteries (SIBs) and Li + batteries (LIBs). However, the real implementation of NFPP has been critically restrained by the inferior intrinsic electronic conductivity. Herein, in situ carbon-coated mesoporous NFPP, obtained via freeze drying and heat treatment, demonstrates highly reversible insertion/extraction of Na + /Li + . Mechanically, the electronic transmission and structural stabilities of NFPP are significantly enhanced by the graphitized carbon coating layer. Chemically, the porous nanosized structure shortens Na + /Li + diffusion paths and increases the contact area between the electrolyte and NFPP, ultimately rendering fast ion diffusion. Greatly, long-lasting cyclability (88.5% capacity retention for over 5000 cycles), decent thermal stability at 60 °C, and impressive electrochemical performances are demonstrated in LIBs. The insertion/extraction mechanisms of NFPP in both SIBs and LIBs are systematically investigated, confirming its small volume expansion and high reversibility. The superior…

Metal–organic frameworks (MOFs), a novel type of porous crystalline material, have aroused widespread interest in lithium-ion batteries (LIBs). The design and preparation of MOF electrodes with a stable structure and excellent electrochemical performance are primary concerns for improving the capacity of LIBs. Among them, two-dimensional (2D) materials with larger specific surface areas, richer active sites, and higher aspect ratios have great potential. We adopted a facile approach to synthesize unique Co-MOF nanosheets with a 2D flaky morphology and a mesoporous structure. In addition, low-temperature calcination increases the specific surface area and improves the porosity to achieve mass transfer. Sample M2 delivers high specific capacities and long lives (1402.0 mA h g –1 after 100 cycles at 500 mA g –1 and 462.4 mA h g –1 after 300 cycles at 1.0 A g –1 ) when the calcination temperature is 200 °C. Significant improvements in the cycle life and stability are attributed to the 2D flaky structure of the M2 sample and the available low-temperature calcination activation, which…

Herein, we describe the solid-state fusion of rod-shaped to honeycomb-shaped cadmium oxide particles (CdO NPs) caused by the process of repeated exposure to acoustic shock waves. Significant changes have been observed in structurally and morphologically dependent properties. For instance, at the 200-shocked condition, the high-pressure CdO-B2 phase is present as a secondary phase wherein all of the rod-shaped particles have been transformed into honeycomb-shaped CdO particles which possess comparatively higher specific-capacitance than CdO nanorods (NRs). The computed specific capacitance values for the 0, 100, and 200 shocked samples at a scan rate of 100 m V s –1 are computed to be 433, 415, and 583 F g –1, respectively. The second-stage decomposition temperature points of the CdO NPs have significantly increased in accordance with the morphological changes from rod to honeycomb patterns such that the values are 343, 526, and 534 °C, respectively, for 0, 100, and 200 shocked conditions. Note that such honeycomb nanostructured CdO particles by shock-wave processing have never been…

A europium(III) metal–organic framework (MOF), namely, {[[(CH 3 ) 2 NH 2 ] 3 Eu 2 (DTTP-2OH) 2 (HCOO)(H 2 O)]·4H 2 O} n ( Eu-MOF, H 4 DTTP-2OH = 2′,5′-dihydroxy-[1,1′:4′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid) has been assembled through solvothermal method. The Eu-MOF is a three-dimensional (3D) (4,4,8)-connected topological framework with binuclear Eu(III) clusters as secondary building units, in which a richly ordered hydrogen bonding network formed among the free H 2 O molecules, dimethylamine cations, and phenolic hydroxyl groups provides a potential pathway for proton conduction. The proton conductivity reaches the category of superionic conductors (σ > 10 –4 S cm –1 ) at room temperature with a maximum conductivity of 1.91 × 10 –3 S cm –1 at 60 °C and 98% RH. Moreover, it also can be used as a fluorescence sensor in aqueous solution with detection limits of 0.14 μM for tetracycline, 0.13 μM for oxytetracycline and 0.11 μM for doxycycline. These results pave new methods for constructing MOFs with high proton conductivity and responsive fluorescence.

Actinide-bearing metal–organic frameworks (MOFs) encompass intriguing structures and properties, but the radioactivity of actinide cripples their applications. Herein, we have constructed a new thorium-based MOF ( Th-BDAT ) as a bifunctional platform for the adsorption and detection of radioiodine, a more radioactive fission product that can readily spread through the atmosphere in its molecular form or via solution as anionic species. The iodine capture within the framework of Th-BDAT from both the vapor phase and the cyclohexane solution has been verified, showing that Th-BDAT features maximum I 2 adsorption capacities ( Q max ) of 959 and 1046 mg/g, respectively. Notably, the Q max of Th-BDAT toward I 2 from cyclohexane solution ranks among the highest value for Th-MOFs reported to date. Furthermore, incorporating highly extended and π-electron-rich BDAT 4– ligands renders Th-BDAT as a luminescent chemosensor whose emission can be selectively quenched by iodate with a detection limit of 1.367 μM. Our findings thus foreshadow promising directions that might unlock the full…

Layered double hydroxide (LDH)-based photocatalysts have attracted more attention in photocatalysis due to their low cost, wide band gaps, and adjustable photocatalytic active sites; however, their low photogenerated carrier separation efficiency limits their photocatalytic efficiency. Herein, a NiAl-LDH/Ni-doped Zn 0.5 Cd 0.5 S (LDH/Ni-ZCS) S-scheme heterojunction is rationally designed and constructed from kinetically and thermodynamically favorable angles. The 15% LDH/1% Ni-ZCS displays comparable photocatalytic hydrogen evolution (PHE) activity with a rate of 6584.0 μmol g –1 h –1, which exceeds by ∼6.14- and ∼1.73-fold those of ZCS and 1% Ni-ZCS, respectively, and outperforms most of the previously reported LDH-based and metal sulfide-based photocatalysts. In addition, the apparent quantum yield of 15% LDH/1% Ni-ZCS reaches 12.1% at 420 nm. In situ X-ray photoelectron spectroscopy, photodeposition, and theoretical calculation reveal the specific transfer path of photogenerated carriers. On this basis, we propose the possible photocatalytic mechanism. The fabrication of the…

The incorporation of Lewis acid–base sites in catalysts has been considered as a significant approach to fabricating bifunctional catalysts with efficient catalytic activity for CO 2 fixation. In this paper, a series of Hafnium-based metal–organic frameworks (Hf-MOFs), NU-912(Hf) and NU-912–X(Hf)–X (X = −NH 2, −Br, −CN, and −I) derivatives assembled by Lewis acidic Hf 6 (μ 3 –O) 4 (μ 3 –OH) 4 (H 2 O) 4 (OH) 4 (Hf 6 ) clusters and Lewis base-attached organic linkers, are successfully synthesized by a facile ligand functionalization method. These isostructural Hf-MOFs, which exhibit diamond channels of 1.3 nm diameter, great chemical stability, and CO 2 adsorption capacity, have been evaluated as catalysts for the CO 2 cycloaddition reaction with epoxides. Catalytic experiments reveal that the micropore environments of these MOFs have an outstanding impact on catalytic activity. Remarkably, NU-912(Hf)–I serves as an efficient heterogeneous catalyst for this catalytic reaction under mild conditions due to the high density of Lewis acid Hf 6 cluster centers and strong Lewis base…

Zero-dimensional (0D) hybrid metal halides are attractive owing to their distinctive structure as well as photoluminescence (PL) characteristics. To discover 0D hybrid metal halides with high photoluminescence quantum yield and good stability is of great significance for white light-emitting diodes (LEDs). Herein, a novel hybrid antimony chloride (CTP) 2 SbCl 5 is synthesized, which shows a bright broad-band orange-red emission peaking at 620 nm under the low energy excitation (365 nm), achieving an excellent photoluminescence quantum yield of 96.8%. In addition, (CTP) 2 SbCl 5 shows an additional emission peaking at 470 nm when excited at high energy (323 nm). PL spectra and density functional theory results demonstrate that the observed dual-band emission originates from the singlet and triplet self-trapped excitons confined in isolated [SbCl 5 ] 2– square pyramids. Moreover, (CTP) 2 SbCl 5 presents relatively superior air stability, and the PL intensity still maintains 78% of the initial PL intensity when exposed to the air for above 2 weeks. Benefiting from high-efficiency PL…

To improve the catalytic performance of metal–organic frameworks (MOFs), creating higher defects is now considered as the most effective strategy, which can not only optimize the Lewis acidity of metal ions but also create more pore space to enhance diffusion and mass transfer in the channels. Herein, the exquisite combination of scarcely reported [In 2 (CO 2 ) 5 (H 2 O) 2 (DMF) 2 ] clusters and 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H 5 BDCP) under solvothermal conditions generated a highly robust nanoporous framework of {[In 2 (BDCP)(DMF) 2 (H 2 O) 2 ](NO 3 )} n ( NUC-65 ) with nanocaged voids (14.1 Å) and rectangular nanochannels (15.94 Å × 11.77 Å) along the a axis. It is worth mentioning that an In(1) ion displays extremely low tetra-coordination modes after the thermal removal of its associated four solvent molecules of H 2 O and DMF. Activated {[In 2 (BDCP)](Br)} n ( NUC-65Br ), as a defective material because of its extremely unsaturated metal centers, could be generated by bromine ion exchange, solvent exchange, and vacuum drying. Catalytic experiments…

Photocatalysis has long been considered a promising technology in green energy and environmental remediation. Since the poor performance of single components greatly limits the practical applications, the construction of heterostructures has become one of the most important technical means to improve the photocatalytic activity. In this work, based on the synthesis of oxygen-vacancy-rich ZnCr 2 O 4 nanocrystals, ZnCr 2 O 4 /ZnIn 2 S 4 composites are prepared via a low-temperature in situ growth, and the oxygen-vacancy-induced Z-scheme heterojunction is successfully constructed. The unique core–shell structure offers a tight interfacial contact, increases the specific surface area, and promotes the rapid charge transfer. Meanwhile, the oxygen-vacancy defect level not only enables wide-bandgap ZnCr 2 O 4 to be excited by visible light enhancing the light absorption, but also provides necessary conditions for the construction of Z-scheme heterojunctions promoting charge separation and migration and allowing more reactive charges. The reaction rates of visible-light-driven…

A highly conductive and rationally constructed metal–organic framework (MOF)-derived metal phosphide with a carbonaceous nanostructure is a meticulous architecture toward the development of electrode materials for energy storage devices. Herein, we report a facile strategy to design and construct a new three-dimensional (3D) Cu-MOF via a solvent diffusion method at ambient temperature, which was authenticated by a single-crystal X-ray diffraction study, revealing a novel topology of (2,4,7)-connected three-nodal net named smm 4 . Nevertheless, the poor conductivity of pristine MOFs is a major bottleneck hindering their capacitance. To overcome this, we demonstrated an MOF-derived Cu 3 P/Cu@NC heterostructure via low-temperature phosphorization of Cu-MOF . The electronic and ionic diffusion kinetics in Cu 3 P/Cu@NC were improved due to the synergistic effects of the heterostructure. The as-prepared Cu 3 P/Cu@NC heterostructure electrode delivers a specific capacity of 540 C g –1 at 1 A g –1 with outstanding rate performance (190 C g –1 at 20 A g –1 ) and cycle stability (91% capacity…

Nowadays, coordination polymers (CPs) are promising candidates as sensory materials for their high sensitivity, improved selectivity, fast responsive nature, as well as good recyclability. However, poor chemical stability often makes their practical usage limited. Herein, employing a mixed ligand approach, we constructed a chemically robust CP, {[Zn 2 L 2 (DPA) 2 ]·3H 2 O} n ( IITKGP-70, IITKGP stands for the Indian Institute of Technology Kharagpur), which exhibited excellent framework robustness not only in water but also over a broad range of pH solutions (pH = 3–11). The developed framework displayed high selectivity and sensitivity for the detection of trivalent Al 3+ ions and toxic hexavalent Cr(VI)-oxo anions in an aqueous medium . The developed framework exhibited an aqueous medium Al 3+ turn-on phenomenon with a limit of detection (LOD) value of 1.29 μM, whereas a turn-off effect was observed for toxic oxo-anions (Cr 2 O 7 2– and CrO 4 2– ) having LOD values of 0.27 and 0.71 μM, respectively. Both turn-on and turn-off mechanisms are speculated via spectroscopic methods…

Tactile sensing with stress and temperature sensing as core elements have shown promising prospects in intelligent robots and the human–machine interface. Mechanoluminescence (ML)-based stress sensing can realize the direct sensing of mechanical stimulation, whereas indirect temperature sensing based on luminescent sensing materials usually requires the stimulation of extra light or force. Herein, a trap-controlled material Sr 2 MgAl 22 O 36:Mn 2+ with bifunctional mechano/thermal sensing applications was developed and investigated in detail. Visualized bright green-emitting ML and thermally stimulated luminescence (TSL) directly and rapidly responded to mechano/thermal dual stimulation in the Sr 2 MgAl 22 O 36:Mn 2+ /PDMS composite film. It is worth mentioning that this study proposed a new idea of direct temperature sensing by the initial intensity of TSL due to thermal–photo energy conversion, unlike previous temperature sensor technology. Based on this, we designed a flexible optical skin with a simple structure and verified its application prospect as a tactile sensing material…

Dielectric capacitors have become an important component in current pulsed power devices and thus have attracted great research interest in recent years. Among all kinds of dielectric materials, the bismuth ferrite (BiFeO 3 )-based ceramic capacitors show possible applications in dielectric energy storage because of their large polarization. However, the relatively high conductivity badly limits the improvement of electric breakdown strength, thus leading to low energy density. Herein, the perovskite end-member La(Mg 2/3 Nb 1/3 )O 3 and sintering aid MnO 2 were simultaneously introduced into BiFeO 3 –SrTiO 3 solid solutions to improve the relaxation features and electric breakdown strength. Accordingly, a high recoverable energy density of 6.3 J/cm 3 and an acceptable efficiency of 74.3% were realized under 450 kV/cm. In addition, the good frequency/thermal stability and superior charge–discharge performances were also realized. This work provides feasible approaches to modify the capacitive energy storage of BiFeO 3 -based relaxor ferroelectric ceramics.

We report the facile photochemical generation of a library of Ni(I)–bpy halide complexes (Ni(I)( R bpy)X (R = t -Bu, H, MeOOC; X = Cl, Br, I) and benchmark their relative reactivity toward competitive oxidative addition and off-cycle dimerization pathways. Structure–function relationships between the ligand set and reactivity are developed, with particular emphasis on rationalizing previously uncharacterized ligand-controlled reactivity toward high energy and challenging C(sp 2 )–Cl bonds. Through a dual Hammett and computational analysis, the mechanism of the formal oxidative addition is found to proceed through an S N Ar-type pathway, consisting of a nucleophilic two-electron transfer between the Ni(I) 3 d ( z 2 ) orbital and the C aryl –Cl σ* orbital, which contrasts the mechanism previously observed for activation of weaker C(sp 2 )–Br/I bonds. The bpy substituent provides a strong influence on reactivity, ultimately determining whether oxidative addition or dimerization even occurs. Here, we elucidate the origin of this substituent influence as arising from perturbations to the…

The development of an efficient and low-cost electrocatalyst for oxygen evolution reaction (OER) is the key to improving the overall efficiency of water electrolysis. Here, we report the design of a three-dimensional (3-D) heterostructured Ni 9 S 8 /Ni 3 S 2 precatalyst composed of unstable Ni 9 S 8 and inert Ni 3 S 2 components, which undergoes in situ electrochemical activation to generate an amorphous-NiOOH/Ni 3 S 2 heterostructured catalyst. In situ Raman spectroscopy combined with ex situ characterizations, such as X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy, reveals that during the activation, Ni 9 S 8 loses the sulfur element to form nickel oxides and eventually transforms to amorphous NiOOH at O 2 -evolving potentials, while the Ni 3 S 2 component is rather inert that its majority in the bulk remains, thus forming a 3-D congee-like NiOOH/Ni 3 S 2 heterostructure with the Ni 3 S 2 crystalline particles randomly dispersed among amorphous NiOOH species. Unlike the sparse heterostructure that consists of a layer of NiOOH on top of Ni…

Based on the principle of heterogeneous catalysis for water electrolysis, electrocatalysts with appropriate electronic structure and photothermal property are expected to drive the oxygen evolution reaction effectively. Herein, amorphous NiS x -coupled nanourchin-like Co 3 O 4 was prepared on nickel foam (NiS x @Co 3 O 4 /NF) and investigated as a electrocatalyst for photothermal-assisted oxygen evolution reaction. The experimental investigations and simulant calculations jointly revealed NiS x @Co 3 O 4 /NF to be of suitable electronic structure and high near-infrared photothermal conversion capability to achieve the oxygen evolution reaction advantageously both in thermodynamics and in kinetics. Relative to Co 3 O 4 /NF and NiS x /NF, better oxygen evolution reaction activity, kinetics, and stability were achieved on NiS x @Co 3 O 4 /NF in 1.0 M KOH owing to the NiS x /Co 3 O 4 synergetic effect. In addition, the oxygen evolution reaction performance of NiS x @Co 3 O 4 /NF can be obviously enhanced under near-infrared light irradiation, since NiS x @Co 3 O 4 can absorb the…

Recent decades have witnessed a major development in broadband near-infrared (NIR)-emitting phosphors because of their potential applications in real-time nondestructive examination. These applications require the emission spectra of phosphors to be as broad as possible for efficient performance. Therefore, a blue-light excited LiInF4: Cr3+ phosphor with a NIR emission covering 700–1400 nm is successfully synthesized. Under 470 nm excitation, it shows broadband emission peaked at 980 nm with the full-width at half maximum of 210 nm. The structure and crystal field environment are investigated in detail, and the LiInF4: Cr3+ possesses a weak crystal field strength and strong electron–phonon coupling. An efficient NIR phosphor-converted light-emitting diode (pc-LED) is fabricated by the prepared LiInF4: Cr3+ phosphor and commercial blue diode chip, generating a NIR radiant flux of 5.54 mW at 150 mA drive current. Finally, the NIR pc-LED is successfully applied to identify the blood vessel distribution of the hand. This work suggests the potential of LiInF4: Cr3+ phosphor in…

High Resolution Image Download MS PowerPoint Slide The complexes [Eu(bpcd)(tta)], [Eu(bpcd)(Coum)], and [Tb(bpcd)(Coum)] [tta = 2-thenoyltrifluoroacetyl-acetonate, Coum = 3-acetyl-4-hydroxy-coumarin, and bpcd = N, N ′-bis(2-pyridylmethyl)- trans -1,2-diaminocyclohexane- N, N ′-diacetate] have been synthesized and characterized from photophysical and thermodynamic points of view. The optical and chiroptical properties of these complexes, such as the total luminescence, decay curves of the Ln(III) luminescence, electronic circular dichroism, and circularly polarized luminescence, have been investigated. Interestingly, the number of coordinated solvent (methanol) molecules is sensitive to the nature of the metal ion. This number, estimated by spectroscopy, is >1 for Eu(III)-based complexes and <1 for Tb(III)-based complexes. A possible explanation for this behavior is provided via the study of the minimum energy structure obtained by density functional theory (DFT) calculations on the model complexes of the diamagnetic Y(III) and La(III) counterparts [Y(bpcd)(tta)], [Y(bpcd)(Coum)],…

A novel sulfur-bridged metal–organic framework (MOF) [Co(TIC4R-I) 0.25 Cl 2 ] · 3CH 3 OH (Co-TIC4R-I) based on thiacalix[4]arene derivatives was successfully obtained using a solvothermal method. Remarkably, adjacent TIC4R-I ligands were linked via Co(II) cations to form a three-dimensional (3D) microporous architecture. Subsequently, Co-TIC4R-I was modified on a glassy carbon electrode ( Co-TIC4R-I/GCE ) to produce an electrochemical sensor for the detection of heavy-metal ions (HMIs), namely, Cd 2+, Pb 2+, Cu 2+, and Hg 2+, in aqueous solutions. It was found that Co-TIC4R-I/GCE exhibited wide linear detection ranges of 0.10–17.00, 0.05–16.00, 0.05–10.00, and 0.80–15.00 μM for Cd 2+, Pb 2+, Cu 2+, and Hg 2+, respectively, in addition to low limit of detection (LOD) values of 0.017, 0.008, 0.016, and 0.007 μM. Moreover, the fabricated sensor employed for the simultaneous detection of these metals has achieved LOD values of 0.0067, 0.0027, 0.0064, and 0.0037 μM for Cd 2+, Pb 2+, Cu 2+, and Hg 2+, respectively. The sensor also exhibited satisfactory selectivity, reproducibility, and…

Zero-dimensional (0D) In-based organic–inorganic metal halides (OIMHs) have received growing interest in recent years as promising luminescent materials. However, the high efficiencies of 0D In-based OIMHs are all dependent on Sb doping in the existing literature. Here, we report a novel 0D In-based OIMH (C 10 H 22 N 2 ) 2 In 2 Br 10, which exhibits intrinsic broadband emission (610 nm), and the photoluminescence quantum yield (PLQY) can reach 70% without Sb doping. (C 10 H 22 N 2 ) 2 In 2 Br 10 shows a typical 0D structure with three different In–Br polyhedra (two octahedra and one tetrahedron) separated by large organic cations. Based on the optical property measurements and theoretical calculations, we demonstrate that (C 10 H 22 N 2 ) 2 In 2 Br 10 is an indirect semiconductor with a band gap of 3.74 eV, and the In–Br inorganic moiety is primarily responsible for the intense emission of (C 10 H 22 N 2 ) 2 In 2 Br 10 . Interestingly, the unique double octahedral configuration in (C 10 H 22 N 2 ) 2 In 2 Br 10 may enhance the structural distortion and stimulate the self-trapped…

Herein, a novel luminescent Zn-LMOF, JLU-MOF109 ([Zn(PBBA)(H 2 O)]·3DMF·2H 2 O, PBBA = 4,4′-(2,6-pyrazinediyl)bis[benzoic acid], DMF = N, N -dimethylformamide), was successfully synthesized under solvothermal conditions. Zinc ions are connected by PBBA ligands to form two-dimensional (2D) layers, and the layers are further propped up through hydrogen-bonding interactions. JLU-MOF109 exhibits good sensitivity to inorganic pollutants, Fe 3+ and Cr 2 O 7 2–, as well as nitro aromatic explosives, 2,4,6-trinitrophenol and 2,4-dinitrophenol. JLU-MOF109 exhibits high K sv (at 10 4 M –1 level) and low limit of detection values (∼10 –6 mol/L) for the abovementioned hazardous pollutants, which is better than a majority of previously reported MOF-based fluorescent sensors. With good stability in the aqueous phase, JLU-MOF109 can serve as a promising chemical sensor for pollutant detection in wastewater.

As a typical cation-exchangeable layered compound, layered titanate has a unique open layered structure. Its excellent physical and chemical properties allow its wide use in the energy, environmental protection, electronics, biology, and other fields. This paper reviews the recent progress in the research on the structure, synthesis, properties, and application of layered titanates. Various reactivities, as well as the advantages and disadvantages, of different synthetic methods are discussed. The reaction mechanism and influencing factors of the ion exchange reaction, intercalation reaction, and exfoliation reaction are analyzed. The latest research progress on layered titanates and their modified products in the fields of photocatalysis, adsorption, electrochemistry, and other applications is summarized. Finally, the future development of layered titanate and its exfoliated product two-dimensional nanosheets is proposed.

Engineering the activity of enzyme-like catalysts should be a top priority to make them superior substitutes for natural enzymes. Herein, a Ce/Zr bimetal–organic framework (Ce/Zr-MOF) was designed and synthesized by a one-pot hydrothermal method, which has enhanced performance in mimicking peroxidase (POD) than its single-metal counterparts. To further comprehend the mechanism of activity enhancement, the role of the bimetallic synergistic catalysis process in H 2 O 2 decomposition and reactive oxygen species formation was elucidated, and the possible dual cycle synergistic catalysis pathway of bimetallic catalysis is proposed for the first time. The enhanced POD-like activity mainly depends on the introduction of Ce, which improved the conductivity and electron-transfer capability of Ce/Zr-MOF and promoted the generation of •OH. Integrated with a hydrogel substrate, a wearable all-solid-state H 2 O 2 sensor for early diagnosis of plant health was produced. The detection limit can be as low as 3.3 μM, which is lower than that of some instrument-based colorimetric methods and has…

High Resolution Image Download MS PowerPoint Slide Recent research on metal–organic frameworks (MOFs) has shown a shift from considering only the crystalline high-porosity phases to exploring their amorphous counterparts. Applying pressure to a crystalline MOF is a common method of amorphization, as MOFs contain large void spaces that can collapse, reducing the accessible surface area. This can be either a desired change or indeed an unwanted side effect of the application of pressure. In either case, understanding the MOF’s pressure response is extremely important. Three such MOFs with varying pore sizes (UiO-66, MOF-808, and NU-1000) were investigated using in situ high-pressure X-ray diffraction and Raman spectroscopy. Partial crystallinity was observed in all three MOFs above 10 GPa, along with some recovery of crystallinity on return to ambient conditions if the frameworks were not compressed above thresholds of 13.3, 14.2, and 12.3 GPa for UiO-66, MOF-808, and NU-1000, respectively. This threshold was marked by an unexpected increase in one or more lattice parameters with…

In recent years, the irrational use of antibiotics has become very widespread. It is necessary to regulate this phenomenon through antibiotic detection. In this work, a series of isomorphic Ln-MOFs (Ln = Tb 3+ and Eu 3+ ) were synthesized from 1,3,5-tri(4-carboxyphenyl)benzene (H 3 L) and Ln 3+ by the solvothermal method for the first time. A series of 1-Eu x Tb 1– x with different luminescence were doped by changing the molar ratio of Tb 3+ and Eu 3+ . Ln 3+ forms a 4-connected 2D network structure through self-assembly with fully deprotonated L 3– . It shows good chemical stability in water, and its luminescence is not affected by aqueous solutions with different pH values. 1-Eu demonstrates rapid and sensitive detection capabilities for MDZ and TET with good recyclability and low detection limits (10 –5 ). In order to increase the practicability of 1-Eu, two portable sensors have been prepared, in which the fluorescent film ( Film@1-Eu ) has a detection limit of 10 –4, and the sensitivity is only less than 10% of the titration results. A portable fluorescent test paper can reach…

Broadband ultraviolet (UV) excitation and red/far-red emission phosphors can effectively convert solar spectrum to enhance photosynthesis and promote morphogenesis in plants. Based on the above application requirements, Eu 3+ single-doped LaAl 1– y Ga y O 3 solid solutions and Eu 3+,Mn 4+ codoped LaAl 0.7 Ga 0.3 O 3 phosphors were designed and synthesized in this work. The LaAl 0.7 Ga 0.3 O 3:0.05Eu 3+ (LAG:Eu 3+ ) phosphor exhibits a strong charge transfer band (CTB) excitation and characteristic 5 D 0 → 7 F 2 transition red emission (619 nm), which is very similar to the luminescence properties of Eu 3+ -organic ligand compound (EuL 3 ). Rietveld refinement studies further revealed that the cation substitution disturbs the site symmetry. The optimal Eu 3+, Mn 4+ co-doped LaAl 0.7 Ga 0.3 O 3 (LAG:Eu,Mn) phosphor possesses a dual-band excitation spectrum in broadband ultraviolet (UVA, UVB) area and a dual-band emission spectrum within red/far-red area. Under the sunlight radiation, the real-time spectrum of luminous laminated glasses fabricated by coating the LAG:Eu,Mn phosphor…

The excited-state manipulation of the phosphorescent iridium(III) complexes plays a vital role in their photofunctional applications. The development of the molecular design strategy promotes the creative findings of novel iridium(III) complexes. The current molecular design strategies for iridium(III) complexes mainly depend on the selective cyclometalation of the ligands with the iridium(III) ion, which is governed by the steric hindrance of the ligand during the cyclometalation. Herein, a new molecular design strategy (i.e., random cyclometalation strategy) is proposed for the effective excited-state manipulation of phosphorescent cyclometalated iridium(III) complexes. Two series of new and separable methoxyl-functionalized isomeric iridium(III) complexes are accessed by a one-pot synthesis via random cyclometalation, resulting in a dramatic tuning of the phosphorescence peak wavelength (∼57 nm) and electrochemical properties attributed to the high sensitivity of their excited states to the position of the methoxyl group. These iridium(III) complexes show intense phosphorescence…

Adding hydrophilic ligands into aqueous solutions for the selective binding of actinides(III) is acknowledged as an advanced strategy in Ln(III)/An(III) separation. In view of the recycling and radioactive waste disposal of the minor actinide, there remains an urgent need to design and develop the appropriate ligand for selective separation of An(III) from Ln(III). Herein, four novel hydrophilic ligands with hard–soft hybrid donors, derived from the pyridine and phenanthroline skeletons, were designed and synthesized as masking agents for selective complexation of An(III) in the aqueous phase. The known N, N, N ′, N ′-tetraoctyl diglycolamide (TODGA) was used as lipophilic extractant in the organic phase for extraction of Ln(III), and a new strategy for the competitive extraction of An(III) and Ln(III) was developed based on TODGA and the above hydrophilic ligands. The optimal hydrophilic ligand of N, N ′-bis(2-hydroxyethyl)-2,9-dicarboxamide-1,10-phenanthroline (2OH-DAPhen) displayed exceptional selectivity toward Am(III) over Ln(III), with the concentrations of HNO 3 ranging from…

Phenolic organic compounds are widely used industrial chemicals that exist extensively in the environment and have a significant impact on human health. 4-Nitrophenol (4-NP) is a typical phenolic organic compound found in aqueous environments. Efficient detection of 4-NP in wastewater is highly challenging due to the complexity of testing environmental samples. Herein, a luminescent lanthanide metal–organic framework (MOF) sensor based on the Eu 3+ ion {[Eu(HL)(L)(H 2 O)]·2H 2 O} n ( EuMOF; H 2 L = 5-(4 H -1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic acid) was successfully synthesized for efficient 4-NP detection in wastewater. Fluorescence sensing experiments revealed that 4-NP could greatly quench the EuMOF fluorescence. Subsequently, EuMOF was applied to 4-NP detection in distilled water, tap water, river water, and treated industrial wastewater, exhibiting high sensitivity, a fast response within 30 s, high selectivity, excellent reusability, and a low detection limit. Finally, the fluorescence quenching mechanism was explored and attributed to competitive absorption of…

The construction of strong metal–support interactions in oxide-supported noble metal nanocatalysts has been considered an emerging and efficient way in improving catalytic performance in biomass-upgrading reactions. Herein, a citric acid (CA)-assisted synthesized ZrO 2 layer with improved oxygen vacancy (O v ) concentrations on a natural clay mineral of halloysite nanotubes (HNTs) was designed. Moreover, Au x Pd y /ZrO 2 @HNTs-zCA catalysts were prepared by loading AuPd bimetal and employed for aerobic oxidation of the lignocellulosic biomass-derived 5-hydroxymethylfurfural (HMF) platform to the bioplastic monomer 2,5-furandicarboxylic acid (FDCA) with water as the solvent. The results of catalytic experiments revealed that the Au 3 Pd 1 /ZrO 2 @HNTs-1.0CA catalyst exhibited excellent catalytic activity at 0.5 MPa O 2, with a satisfactory FDCA yield of 99.5% and outstanding FDCA formation rate of 1057.9 mmol·g –1 ·h –1 . The improved O v concentration in the ZrO 2 support enhanced the adsorption and activation ability of the catalyst for O 2, and a higher Lewis acid concentration…

In this paper, Pr 0.7 Sr 0.3 Co 1– x Ru x O 3 perovskite oxides were synthesized by the sol–gel method as bifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The overpotentials of PSCR0.05 against HER and OER at 10 mA cm –2 were 319 and 321 mV in alkaline medium, respectively. The Tafel slopes of HER and OER were 87.32 and 118.1 mV/dec, respectively. PSCR0.05 showed the largest electrochemical active area, the smallest charge transfer resistance, and excellent long-term durability. Meanwhile, the PSCR0.05 electrocatalyst was applied for overall water splitting and its cell voltage was maintained at 1.77 V at 10 mA cm –2 . The super-exchange interaction between adjacent RuO 6 –CoO 6 octahedra in perovskite made of PSCR0.05 contains sufficient active sites (such as Co 2+ /Co 3+, Ru 3+ /Ru 4+, and O 2 2– /O – ). The increase of surface oxygen vacancy and active site is the main reason for the improvement of difunctional catalyst performance. In this work, the electrocatalytic performance of perovskite-type oxides was further optimized by…

Electrochemical nitrogen reduction reaction (NRR) is a promising method for ammonia synthesis under ambient conditions. However, the NRR performance is limited to an extremely strong N≡N bond in N 2 and the competing hydrogen evolution reaction. Introducing oxygen vacancies (OVs) has been considered as a forceful means to accelerate the sluggish NRR reaction kinetics. Herein, we reported the design of Fe-doped NiMoO 4 catalysts for NRR. Fe doping can increase the amount of OVs in the catalyst and contribute to lattice strain enhancement, thereby leading to the improvement of the electron transport rate and catalytic active for NRR. In 0.1 M Na 2 SO 4 solution, the 5% Fe-NiMoO 4 catalyst achieves a NH 3 yield rate of 15.36 μg h –1 mg cat. –1 and a Faradaic efficiency of 26.85% under −0.5 V versus RHE. Furthermore, the 5% Fe-NiMoO 4 catalyst exhibits excellent stability (up to 13 h) during the reaction.

In order to explore the catalytic effect of different Lewis acid sites (LASs) in the CO 2 cycloaddition reaction, different secondary building units and N-rich organic ligand 4,4′,4″- s -triazine-1,3,5-triyltri- p -aminobenzoate were assembled to construct six reported MOF materials: [Cu 3 (tatab) 2 (H 2 O) 3 ]·8DMF·9H 2 O ( 1 ), [Cu 3 (tatab) 2 (H 2 O) 3 ]·7.5H 2 O ( 2 ), [Zn 4 O(tatab) 2 ]·3H 2 O·17DMF ( 3 ), [In 3 O(tatab) 2 (H 2 O) 3 ](NO 3 )·15DMA ( 4 ), [Zr 6 O 4 (OH) 7 (tatab)(Htatab) 3 (H 2 O) 3 ]· x Guest ( 5 ), and [Zr 6 O 4 (OH) 4 (tatab) 4 (H 2 O) 3 ]· x Guest ( 6 ) (DMF = N, N -dimethylformamide, and DMA = N, N -dimethylacetamide). Large pore sizes of compound 2 enhance the concentration of substrates, and the multi-active sites inside its framework synergistically promote the process of the CO 2 cycloaddition reaction. Such advantages endow compound 2 with the best catalytic performance among the six compounds and surpass many of the reported MOF-based catalysts. Meanwhile, the comparison of the catalytic efficiency indicated that Cu-paddlewheel and Zn 4 O display…