The 100 most-cited articles in Angewandte Chemie, 2021

Abstract The electrochemical carbon dioxide reduction reaction (CO 2 RR) provides an attractive approach to convert renewable electricity into fuels and feedstocks in the form of chemical bonds. Among the different CO 2 RR pathways, the conversion of CO 2 into CO is considered one of the most promising candidate reactions because of its high technological and economic feasibility. Integrating catalyst and electrolyte design with an understanding of the catalytic mechanism will yield scientific insights and promote this technology towards industrial implementation. Herein, we give an overview of recent advances and challenges for the selective conversion of CO 2 into CO. Multidimensional catalyst and electrolyte engineering for the CO 2 RR are also summarized. Furthermore, recent studies on the large‐scale production of CO are highlighted to facilitate industrialization of the electrochemical reduction of CO 2 . To conclude, the remaining technological challenges and future directions for the industrial application of the CO 2 RR to generate CO are highlighted.

Active, selective and stable catalysts are imperative for sustainable energy conversion, and engineering materials with such properties are highly desired. High-entropy alloys (HEAs) offer a vast compositional space for tuning such properties. Too vast, however, to traverse without the proper tools. Here, we report the use of Bayesian optimization on a model based on density functional theory (DFT) to predict the most active compositions for the electrochemical oxygen reduction reaction (ORR) with the least possible number of sampled compositions for the two HEAs Ag-Ir-Pd-Pt-Ru and Ir-Pd-Pt-Rh-Ru. The discovered optima are then scrutinized with DFT and subjected to experimental validation where optimal catalytic activities are verified for Ag-Pd, Ir-Pt, and Pd-Ru binary alloys. This study offers insight into the number of experiments needed for optimizing the vast compositional space of multimetallic alloys which has been determined to be on the order of 50 for ORR on these HEAs.

Abstract Dendrite growth and by‐products in Zn metal aqueous batteries have impeded their development as promising energy storage devices. We utilize a low‐cost additive, glucose, to modulate the typical ZnSO 4 electrolyte system for improving reversible plating/stripping on Zn anode for high‐performance Zn ion batteries (ZIBs). Combing experimental characterizations and theoretical calculations, we show that the glucose in ZnSO 4 aqueous environment can simultaneously modulate solvation structure of Zn 2+ and Zn anode‐electrolyte interface. The electrolyte engineering can alternate one H 2 O molecule from the primary Zn 2+ ‐6H 2 O solvation shell and restraining side reactions due to the decomposition of active water. Concomitantly, glucose molecules are inclined to absorb on the surface of Zn anode, suppressing the random growth of Zn dendrite. As a proof of concept, a symmetric cell and Zn‐MnO 2 full cell with glucose electrolyte achieve boosted stability than that with pure ZnSO 4 electrolyte.

Abstract Piezocatalysis, a newly emerging catalysis technology that relies on the piezopotential and piezoelectric properties of the catalysts, is attracting unprecedented research enthusiasm for applications in energy conversion, organic synthesis, and environmental remediation. Despite the rapid development in the past three years, the mechanism of piezocatalysis is still under debate. A fundamental understanding of the working principles of this technology should enable the future design and optimization of piezocatalysts. Herein, we provide an overview of the two popular theories used to explain the observed piezocatalysis: energy band theory and screening charge effect. A comprehensive discussion and clarification of the differences, relevance, evidence, and contradiction of the two mechanisms are provided. Finally, challenges and perspectives for future mechanistic studies are highlighted. Hopefully, this Review can help readers gain a better understanding of piezocatalysis and enable its application in their own research.

Abstract Lead‐halide perovskites (LHPs), in the form of both colloidal nanocrystals (NCs) and thin films, have emerged over the past decade as leading candidates for next‐generation, efficient light‐emitting diodes (LEDs) and solar cells. Owing to their high photoluminescence quantum yields (PLQYs), LHPs efficiently convert injected charge carriers into light and vice versa. However, despite the defect‐tolerance of LHPs, defects at the surface of colloidal NCs and grain boundaries in thin films play a critical role in charge‐carrier transport and nonradiative recombination, which lowers the PLQYs, device efficiency, and stability. Therefore, understanding the defects that play a key role in limiting performance, and developing effective passivation routes are critical for achieving advances in performance. This Review presents the current understanding of defects in halide perovskites and their influence on the optical and charge‐carrier transport properties. Passivation strategies toward improving the efficiencies of perovskite‐based LEDs and solar cells are also discussed.

Abstract Fuel cells are an incredibly powerful renewable energy technology, but their broad applications remains lagging because of the high cost and poor reliability of cathodic electrocatalysts for the oxygen reduction reaction (ORR). This review focuses on the recent progress of ORR electrocatalysts in fuel cells. More importantly, it highlights the fundamental problems associated with the insufficient activity translation from rotating disk electrode to membrane electrode assembly in the fuel cells. Finally, for the atomic‐level in‐depth information on ORR catalysts in fuel cells, potential perspectives are suggested, including large‐scale preparation, unified assessment criteria, advanced interpretation techniques, advanced simulation and artificial intelligence. This review aims to provide valuable insights into the fundamental science and technical engineering for efficient ORR electrocatalysts in fuel cells.

Abstract MXenes have attracted great interests as supercapacitors due to their metallic conductivity, high density, and hydrophilic nature. Herein we report Ti3C2‐Cu/Co hybrids via molten salt etching in which the existence of metal atoms and their interactions with MXene via surficial O atoms were elucidated by XAFS for the first time. The electrochemical investigation of Ti3C2‐Cu electrode demonstrated the pseudocapacitive contribution of Cu and a splendid specific capacitance of 885.0 F g−1 at 0.5 A g−1 in 1.0 M H2SO4. Symmetric supercapacitor Ti3C2‐Cu//Ti3C2‐Cu was demonstrated with operating voltage of 1.6 V, areal capacitance of 290.5 mF cm−2 at 1 mA cm−2, and stability over 10 000 cycles. It delivered an areal energy density of 103.3 μWh cm−2 at power density of 0.8 mW cm−2, based on which a supercapacitor pouch was fabricated. It provides deeper insights into the molten salt mechanism and strategies for designing MXene‐based materials for electrochemical energy storage.

Abstract The development of highly active and stable bifunctional noble‐metal‐based electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is a crucial goal for clean and renewable energy, which still remains challenging. Herein, we report an efficient and stable catalyst comprising a Co single atom incorporated in an RuO2 sphere for HER and OER, in which the Co single atom in the RuO2 sphere was confirmed by XAS, AC‐STEM, and DFT. This tailoring strategy uses a Co single atom to modify the electronic structures of the surrounding Ru atoms and thereby remarkably elevates the electrocatalytic activities. The catalyst requires ultralow overpotentials, 45 mV for HER and 200 mV for OER, to deliver a current density of 10 mA cm−2. The theoretical calculations reveal that the energy barriers for HER and OER are lowered after incorporation of a cobalt single atom.

Abstract Antisolvent addition has been widely studied in crystallization in the pharmaceutical industries by breaking the solvation balance of the original solution. Here we report a similar antisolvent strategy to boost Zn reversibility via regulation of the electrolyte on a molecular level. By adding for example methanol into ZnSO4electrolyte, the free water and coordinated water in Zn2+solvation sheath gradually interact with the antisolvent, which minimizes water activity and weakens Zn2+solvation. Concomitantly, dendrite‐free Zn deposition occurs via change in the deposition orientation, as evidenced by in situ optical microscopy. Zn reversibility is significantly boosted in antisolvent electrolyte of 50 % methanol by volume (Anti‐M‐50 %) even under harsh environments of −20 °C and 60 °C. Additionally, the suppressed side reactions and dendrite‐free Zn plating/stripping in Anti‐M‐50 % electrolyte significantly enhance performance of Zn/polyaniline coin and pouch cells. We demonstrate this low‐cost strategy can be readily generalized to other solvents, indicating its practical…

Abstract Water electrolysis that results in green hydrogen is the key process towards a circular economy. The supply of sustainable electricity and availability of oxygen evolution reaction (OER) electrocatalysts are the main bottlenecks of the process for large‐scale production of green hydrogen. A broad range of OER electrocatalysts have been explored to decrease the overpotential and boost the kinetics of this sluggish half‐reaction. Co‐, Ni‐, and Fe‐based catalysts have been considered to be potential candidates to replace noble metals due to their tunable 3d electron configuration and spin state, versatility in terms of crystal and electronic structures, as well as abundance in nature. This Review provides some basic principles of water electrolysis, key aspects of OER, and significant criteria for the development of the catalysts. It provides also some insights on recent advances of Co‐, Ni‐, and Fe‐based oxides and a brief perspective on green hydrogen production and the challenges of water electrolysis.

Abstract Green carbon science is defined as the “study and optimization of the transformation of carbon‐containing compounds and the relevant processes involved in the entire carbon cycle from carbon resource processing, carbon energy utilization, CO2 fixation, and carbon recycling to utilize carbon resources efficiently and minimize the net CO2 emission.”[1] Green carbon science is related closely to carbon neutrality, and relevant fields have developed quickly in the last decade. In this Minireview, we propose the concept of carbon energy index, and the recent progress in petroleum refining, and the production of liquid fuels, chemicals, and materials using coal, methane, CO2, biomass, and waste plastics is highlighted in combination with green carbon science. An outlook for these important fields is provided in the final section.

Abstract In electrochemical energy storage and conversion systems, the anodic oxygen evolution reaction (OER) accounts for a large proportion of the energy consumption. The electrocatalytic urea oxidation reaction (UOR) is one of the promising alternatives to OER, owing to its low thermodynamic potential. However, owing to the sluggish UOR kinetics, its potential in practical use has not been unlocked. Herein, we developed a tungsten‐doped nickel catalyst (Ni‐WO x ) with superior activity towards UOR. The Ni‐WO x catalyst exhibited record fast reaction kinetics (440 mA cm −2 at 1.6 V versus reversible hydrogen electrode) and a high turnover frequency of 0.11 s −1 , which is 4.8 times higher than that without W dopants. In further experiments, we found that the W dopant regulated the local charge distribution of Ni atoms, leading to the formation of Ni 3+ sites with superior activity and thus accelerating the interfacial catalytic reaction. Moreover, when we integrated Ni‐WO x into a CO 2 flow electrolyzer, the cell voltage is reduced to 2.16 V accompanying with ≈98 % Faradaic…

Abstract Atomic substitutions at the tetrahedral site (ATd) could theoretically achieve an efficient optimization of the charge at the octahedral site (BOh) through the ATd‐O‐BOh interactions in the spinel oxides (AB2O4). Despite substantial progress having been made, the precise control and adjustment of the spinel oxides are still challenging owing to the complexity of their crystal structure. In this work, we demonstrate a simple solvent method to tailor the structures of spinel oxides and use the spinel oxide composites (ACo2O4/NCNTs, A=Mn, Co, Ni, Cu, Zn) for oxygen electrocatalysis. The optimized MnCo2O4/NCNTs exhibit high activity and excellent durability for oxygen reduction/evolution reactions. Remarkably, the rechargeable liquid Zn–air battery equipped with a MnCo2O4/NCNTs cathode affords a specific capacity of 827 mAh gZn−1 with a high power density of 74.63 mW cm−2 and no voltage degradation after 300 cycles at a high charging–discharging rate (5 mA cm−2). The density functional theory (DFT) calculations reveal that the substitution could regulate the ratio of Co3+/Co2+…

Abstract Present one‐step N 2 fixation is impeded by tough activation of the N≡N bond and low selectivity to NH 3 . Here we report fixation of N 2 ‐to‐NH 3 can be decoupled to a two‐step process with one problem effectively solved in each step, including: 1) facile activation of N 2 to NO x − by a non‐thermal plasma technique, and 2) highly selective conversion of NO x − to NH 3 by electrocatalytic reduction. Importantly, this process uses air and water as low‐cost raw materials for scalable ammonia production under ambient conditions. For NO x − reduction to NH 3 , we present a surface boron‐rich core–shell nickel boride electrocatalyst. The surface boron‐rich feature is the key to boosting activity, selectivity, and stability via enhanced NO x − adsorption, and suppression of hydrogen evolution and surface Ni oxidation. A significant ammonia production of 198.3 μmol cm −2 h −1 was achieved, together with nearly 100 % Faradaic efficiency.

Abstract It is still of great difficulty to develop the non‐platinum catalyst with high catalytic efficiency towards hydrogen evolution reaction via the strategies till now. Therefore, it is necessary to develop the new methods of catalyst designing. Here, we put forward the catalyst designed by the electronic metal–support interaction (EMSI), which is demonstrated to be a reliable strategy to find out the high‐efficiency catalyst. We carried out the density functional theory calculation first to design the proper EMSI of the catalyst. We applied the model of M1‐M2‐X (X=C, N, O) during the calculation. Among the catalysts we chose, the EMSI of Rh1TiC, with the active sites of Rh1‐Ti2C2, is found to be the most proper one for HER. The electrochemical experiment further demonstrated the feasibility of the EMSI strategy. The single atomic site catalyst of Rh1‐TiC exhibits higher catalytic efficiency than that of state‐of‐art Pt/C. It achieves a small overpotential of 22 mV and 86 mV at the at the current density of 10 mA cm −2 and 100 mA cm −2 in acid media, with a Tafel slope of 25 mV…

Abstract High‐entropy oxides (HEOs), a new concept of entropy stabilization, exhibit unique structures and fascinating properties, and are thus important class of materials with significant technological potential. However, the conventional high‐temperature synthesis techniques tend to afford micron‐scale HEOs with low surface area, and the catalytic activity of available HEOs is still far from satisfactory because of their limited exposed active sites and poor intrinsic activity. Here we report a low‐temperature plasma strategy for preparing defect‐rich HEOs nanosheets with high surface area, and for the first time employ them for 5‐hydroxymethylfurfural (HMF) electrooxidation. Owing to the nanosheets structure, abundant oxygen vacancies, and high surface area, the quinary (FeCrCoNiCu)3O4 nanosheets deliver improved activity for HMF oxidation with lower onset potential and faster kinetics, outperforming that of HEOs prepared by high‐temperature method. Our method opens new opportunities for synthesizing nanostructured HEOs with great potential applications.

Abstract The oxygen evolution reaction (OER) is a key reaction for many electrochemical devices. To date, many OER electrocatalysts function well in alkaline media, but exhibit poor performances in neutral and acidic media, especially the acidic stability. Herein, sodium‐decorated amorphous/crystalline RuO 2 with rich oxygen vacancies (a/c‐RuO 2 ) was developed as a pH‐universal OER electrocatalyst. The a/c‐RuO 2 shows remarkable resistance to acid corrosion and oxidation during OER, which leads to an extremely high catalytic stability, as confirmed by a negligible overpotential increase after continuously catalyzing OER for 60 h at pH=1. Besides, a/c‐RuO 2 also exhibits superior OER activities to commercial RuO 2 and most reported OER catalysts under all pH conditions. Theoretical calculations indicated that the introduction of Na dopant and oxygen vacancy in RuO 2 weakens the adsorption strength of the OER intermediates by engineering the d ‐band center, thereby lowering the energy barrier for OER.

Abstract Rechargeable aqueous Zn batteries are potential for large‐scale electrochemical energy storage due to their low cost and high security. However, Zn metal anode suffers from the dendritic growth and interfacial hydrogen evolution reaction (HER), resulting in the deterioration of electrode/battery performance. Here we propose that both dendrites and HER are related to the water participated Zn 2+ solvation structure‐Zn(H 2 O) 6 2+ and thus can be resolved by transforming Zn(H 2 O) 6 2+ to an anion‐type water‐free solvation structure‐ZnCl 4 2− , which is achieved in traditional ZnSO 4 aqueous electrolyte after adding chloride salt with a bulky cation (1‐ethyl‐3‐methylimidazolium chloride). The elimination of cation‐water interaction suppresses HER, while the electrostatic repulsion between Zn tips and the anion solvation structure inhibits dendrite formation. As a result, the electrolyte shows uniform Zn deposition with an average Zn plating/stripping Coulombic efficiency of ≈99.9 %, enabling a capacity retention of 78.8 % after 300 cycles in anode‐free Zn batteries with…

Abstract Abundant and affordable methane is not only a high‐quality fossil fuel, it is also a raw material for the synthesis of value‐added chemicals. Solar‐energy‐driven conversion of methane offers a promising approach to directly transform methane to valuable energy sources under mild conditions, but remains a great challenge at present. In this Review, recent advances in the photocatalytic conversion of methane are systematically summarized. Insights into the construction of effective semiconductor‐based photocatalysts from the perspective of light‐absorption units and active centers are highlighted and discussed in detail. The performance of various photocatalysts in the conversion of methane is presented, with the photooxidation classified according to the oxidant systems. Lastly, challenges and future perspectives in the photocatalytic oxidation of methane are described.

Abstract Electrocatalytic C−N bond coupling to convert CO 2 and N 2 molecules into urea under ambient conditions is a promising alternative to harsh industrial processes. However, the adsorption and activation of inert gas molecules and then the driving of the C–N coupling reaction is energetically challenging. Herein, novel Mott–Schottky Bi‐BiVO 4 heterostructures are described that realize a remarkable urea yield rate of 5.91 mmol h −1 g −1 and a Faradaic efficiency of 12.55 % at −0.4 V vs. RHE. Comprehensive analysis confirms the emerging space–charge region in the heterostructure interface not only facilitates the targeted adsorption and activation of CO 2 and N 2 molecules on the generated local nucleophilic and electrophilic regions, but also effectively suppresses CO poisoning and the formation of endothermic *NNH intermediates. This guarantees the desired exothermic coupling of *N=N* intermediates and generated CO to form the urea precursor, *NCON*.

Abstract The catalytic activity of metal clusters is closely related with the support; however, knowledge on the influence of the support on the catalytic activity is scarce. We demonstrate that Pt nanoclusters (NCs) anchored on porous TiO 2 nanosheets with rich oxygen vacancies ( V O ‐rich Pt/TiO 2 ) and deficient oxygen vacancies ( V O ‐deficient Pt/TiO 2 ), display significantly different catalytic activity for the hydrogen evolution reaction (HER), in which V O ‐rich Pt/TiO 2 shows a mass activity of 45.28 A mg Pt −1 at −0.1 V vs. RHE, which is 16.7 and 58.8 times higher than those of V O ‐deficient Pt/TiO 2 and commercial Pt/C, respectively. DFT calculations and in situ Raman spectra suggest that porous TiO 2 with rich oxygen vacancies can simultaneously achieve reversed charge transfer (electrons transfer from TiO 2 to Pt NCs) and enhanced hydrogen spillover from Pt NCs to the TiO 2 support, which leads to electron‐rich Pt NCs being amenable to proton reduction of absorbed H*, as well as the acceleration of hydrogen desorption at Pt catalytic sites—both promoting the HER. Our…

Abstract Oxygen reduction reaction (ORR) activity can be effectively tuned by modulating the electron configuration and optimizing the chemical bonds. Herein, a general strategy to optimize the activity of metal single‐atoms is achieved by the decoration of metal clusters via a coating–pyrolysis–etching route. In this unique structure, the metal clusters are able to induce electron redistribution and modulate M−N species bond lengths. As a result, M‐ACSA@NC exhibits superior ORR activity compared with the nanoparticle‐decorated counterparts. The performance enhancement is attributed to the optimized intermediates desorption benefiting from the unique electronic configuration. Theoretical analysis reinforces the significant roles of metal clusters by correlating the ORR activity with cluster‐induced charge transfer. As a proof‐of‐concept, various metal–air batteries assembled with Fe‐ACSA@NC deliver remarkable power densities and capacities. This strategy is an effective and universal technique for electron modulation of M−N−C, which shows great potential in application of energy…

Abstract The promoted activity and enhanced selectivity of electrocatalysts is commonly ascribed to specific structural features such as surface facets, morphology, and atomic defects. However, unraveling the factors that really govern the direct electrochemical reduction of CO2 (CO2RR) is still very challenging since the surface state of electrocatalysts is dynamic and difficult to predict under working conditions. Moreover, theoretical predictions from the viewpoint of thermodynamics alone often fail to specify the actual configuration of a catalyst for the dynamic CO2RR process. Herein, we re‐survey recent studies with the emphasis on revealing the dynamic chemical state of Cu sites under CO2RR conditions extracted by in situ/operando characterizations, and further validate a critical link between the chemical state of Cu and the product profile of CO2RR. This point of view provides a generalizable concept of dynamic chemical‐state‐driven CO2RR selectivity that offers an inspiration in both fundamental understanding and efficient electrocatalysts design.

Abstract The exploitation of highly efficient carbon dioxide reduction (CO2RR) electrocatalyst for methane (CH4) electrosynthesis has attracted great attention for the intermittent renewable electricity storage but remains challenging. Here, N‐heterocyclic carbene (NHC)‐ligated copper single atom site (Cu SAS) embedded in metal–organic framework is reported (2Bn‐Cu@UiO‐67), which can achieve an outstanding Faradaic efficiency (FE) of 81 % for the CO2 reduction to CH4 at −1.5 V vs. RHE with a current density of 420 mA cm−2. The CH4 FE of our catalyst remains above 70 % within a wide potential range and achieves an unprecedented turnover frequency (TOF) of 16.3 s−1. The σ donation of NHC enriches the surface electron density of Cu SAS and promotes the preferential adsorption of CHO* intermediates. The porosity of the catalyst facilitates the diffusion of CO2 to 2Bn‐Cu, significantly increasing the availability of each catalytic center.

Abstract Surface terminations of two‐dimensional MXene (Ti 3 C 2 T x ) considerably impact its physicochemical properties. Commonly used etching methods usually introduce ‐F surface terminations or metallic impurities in MXene. We present a new molten‐salt‐assisted electrochemical etching method to synthesize fluorine‐free Ti 3 C 2 Cl 2 . Using electrons as reaction agents, cathode reduction and anode etching can be spatially isolated; thus, no metallics are present in the Ti 3 C 2 Cl 2 product. The surface terminations can be in situ modified from −Cl to −O and/or −S, which considerably shortens the modification steps and enriches the variety of surface terminations. The obtained −O‐terminated Ti 3 C 2 T x are excellent electrode materials for supercapacitors, exhibiting capacitances of 225 F g −1 at 1.0 Ag −1 , good rate performance (91.1 % at 10 Ag −1 ), and excellent capacitance retention (100 % after 10000 charge/discharge cycles at 10 Ag −1 ), which is superior to multi‐layered Ti 3 C 2 T x prepared by other etching methods.

Abstract Seawater electrolysis to produce hydrogen is a critical technology in marine energy projects; however, the severe anode corrosion caused by the highly concentrated chloride is a key issue should be addressed. In this work, we discover that the addition of sulfate in electrolyte can effectively retard the corrosion of chloride ions to the anode. We take nickel foam as the example and observe that the addition of sulfate can greatly improve the corrosion resistance, resulting in prolonged operating stability. Theoretical simulations and in situ experiments both demonstrate that sulfate anions can be preferentially adsorbed on anode surface to form a negative charge layer, which repulses the chloride ions away from the anode by electrostatic repulsion. The repulsive effect of the adsorbed sulfate is also applicable in highly‐active catalyst (nickel iron layered double hydroxide) on nickel foam, which shows ca. 5 times stability of that in traditional electrolyte.

Abstract Solid‐state lithium batteries (SSLBs) are promising owing to enhanced safety and high energy density but plagued by the relatively low ionic conductivity of solid‐state electrolytes and large electrolyte–electrode interfacial resistance. Herein, we design a poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP)‐based polymer‐in‐salt solid electrolyte (PISSE) with high room‐temperature ionic conductivity (1.24×10−4 S cm−1) and construct a model integrated TiO2/Li SSLB with 3D fully infiltration of solid electrolyte. With forming aggregated ion clusters, unique ionic channels are generated in the PISSE, providing much faster Li+transport than common polymer electrolytes. The integrated device achieves maximized interfacial contact and electrochemical and mechanical stability, with performance close to liquid electrolyte. A pouch cell made of 2 SSLB units in series shows high voltage plateau (3.7 V) and volumetric energy density comparable to many commercial thin‐film batteries.

Abstract A two‐dimensional (2D) laminar membrane with Li+ selective transport channels is obtained by stacking MXene nanosheets with the introduction of poly(sodium 4‐styrene sulfonate) (PSS) with active sulfonate sites, which exhibits excellent Li+ selectivity from ionic mixture solutions of Na+, K+, and Mg2+. The Li+ permeation rate through the MXene@PSS composite membrane is as high as 0.08 mol m−2 h−1, while the Li+/Mg2+, Li+/Na+, and Li+/K+ selectivities are 28, 15.5, and 12.7, respectively. Combining the simulation and experimental results, we further confirm that the highly selective rapid transport of partially dehydrated Li+ within subnanochannels can be attributed to the precisely controlled interlayer spacing and the relatively weaker ion‐terminal (−SO3−) interaction. This study deepens the understanding of ion‐selective permeation in confined channels and provides a general membrane design concept.

Abstract Efficient organic emitters in the deep‐red region are rare due to the “energy gap law”. Herein, multiple boron (B)‐ and nitrogen (N)‐atoms embedded polycyclic heteroaromatics featuring hybridized π‐bonding/ non‐bonding molecular orbitals are constructed, providing a way to overcome the above luminescent boundary. The introduction of B‐phenyl‐B and N‐phenyl‐N structures enhances the electronic coupling of those para‐positioned atoms, forming restricted π‐bonds on the phenyl‐core for delocalized excited states and thus a narrow energy gap. The mutually ortho‐positioned B‐ and N‐atoms also induce a multi‐resonance effect on the peripheral skeleton for the non‐bonding orbitals, creating shallow potential energy surfaces to eliminate the high‐frequency vibrational quenching. The corresponding deep‐red emitters with peaks at 662 and 692 nm exhibit narrow full‐width at half‐maximums of 38 nm, high radiative decay rates of ca. 10 8 s −1 , ≈100 % photo‐luminescence quantum yields and record‐high maximum external quantum efficiencies of ca. 28 % in a normal planar organic…

Abstract Zn dendrite issue was intensively studied via tuning zinc ion flux. pH change seriously influences dendrite formation, while its importance has not been revealed. Here, we construct a N‐modification graphdiyne interface (NGI) to stabilize pH by mediating hydrated zinc ion desolvation. Operando pH detection reveals pH stabilization by NGI. This works with pores in NGI to achieve dendrite‐free Zn deposition and an increased symmetric cell lifespan by 116 times. Experimental and theoretical results owe pH stabilization to desolvation with a reduced activation energy achieved by electron transfer from solvation sheath to N atom. The efficient desolvation ensures that electron directly transfers from substrate to Zn2+ (rather than the coordinated H2O), avoiding O−H bond splitting. Hence, Zn‐V6O13 battery achieves a long lifespan at 20.65 mA cm−2 and 1.07 mAh cm−2. This work reveals the significance of interface pH and provides a new approach to address Zn dendrite issue.

Abstract The single‐atom enzyme (SAE) is a novel type of nanozyme that exhibits extraordinary catalytic activity. Here, we constructed a PEGylated manganese‐based SAE (Mn/PSAE) by coordination of single‐atom manganese to nitrogen atoms in hollow zeolitic imidazolate frameworks. Mn/PSAE catalyzes the conversion of cellular H 2 O 2 to . OH through a Fenton‐like reaction; it also promotes the decomposition of H 2 O 2 to O 2 and continuously catalyzes the conversion of O 2 to cytotoxic . O 2 − via oxidase‐like activity. The catalytic activity of Mn/PSAE is more pronounced in the weak acidic tumor environment; therefore, these cascade reactions enable the sufficient generation of reactive oxygen species (ROS) and effectively kill tumor cells. The prominent photothermal conversion property of the amorphous carbon can be utilized for photothermal therapy. Hence, Mn/PSAE exhibits significant therapeutic efficacy through tumor microenvironment stimulated generation of multiple ROS and photothermal activity.

Abstract Aqueous Zn‐storage behaviors of MoS2‐based cathodes mainly rely on the ion‐(de)intercalation at edge sites but are limited by the inactive basal plane. Herein, an in‐situ molecular engineering strategy in terms of structure defects manufacturing and O‐doping is proposed for MoS2 (designated as D‐MoS2‐O) to unlock the inert basal plane, expand the interlayer spacing (from 6.2 to 9.6 Å), and produce abundant 1T‐phase. The tailored D‐MoS2‐O with excellent hydrophilicity and high conductivity allows the 3D Zn2+ transport along both the ab plane and c‐axis, thus achieving the exceptional high rate capability. Zn2+ diffusion through the basal plane is verified by DFT computations. As a proof of concept, the wearable quasi‐solid‐state rechargeable Zn battery employing the D‐MoS2‐O cathode operates stably even under severe bending conditions, showing great application prospects. This work opens a new window for designing high‐performance layered cathode materials for aqueous Zn‐ion batteries.

Abstract Precisely regulating the electronic structures of metal active species is highly desirable for electrocatalysis. However, carbon with inert surface provide weak metal–support interaction, which is insufficient to modulate the electronic structures of metal nanoparticles. Herein, we propose a new method to control the electrocatalytic behavior of supported metal nanoparticles by dispersing single metal atoms on an O‐doped graphene. Ideal atomic metal species are firstly computationally screened. We then verify this concept by deposition of Ru nanoparticles onto an O‐doped graphene decorated with single metal atoms (e.g., Fe, Co, and Ni) for hydrogen evolution reaction (HER). Consistent with theoretical predictions, such hybrid catalysts show outstanding HER performance, much superior to other reported electrocatalysts such as the state‐of‐the‐art Pt/C. This work offers a new strategy for modulating the activity and stability of metal nanoparticles for electrocatalysis processes.

Abstract Heteroatom doped atomically dispersed Fe1‐NC catalysts have been found to show excellent activity toward oxygen reduction reaction (ORR). However, the origin of the enhanced activity is still controversial because the structure‐function relationship governing the enhancement remains elusive. Herein, sulfur(S)‐doped Fe1‐NC catalyst was obtained as a model, which displays a superior activity for ORR towards the traditional Fe‐NC materials. 57Fe Mössbauer spectroscopy and electron paramagnetic resonance spectroscopy revealed that incorporation of S in the second coordination sphere of Fe1‐NC can induce the transition of spin polarization configuration. Operando 57Fe Mössbauer spectra definitively identified the low spin single‐Fe3+‐atom of C‐FeN4‐S moiety as the active site for ORR. Moreover, DFT calculations unveiled that lower spin state of the Fe center after the S doping promotes OH* desorption process. This work elucidates the underlying mechanisms towards S doping for enhancing ORR activity, and paves a way to investigate the function of broader heteroatom doped Fe1‐NC…

Abstract Noticeable pseudo‐capacitance behavior out of charge storage mechanism (CSM) has attracted intensive studies because it can provide both high energy density and large output power. Although cyclic voltammetry is recognized as the feasible electrochemical technique to determine it quantitatively in the previous works, the results are inferior due to uncertainty in the definitions and application conditions. Herein, three successive treatments, including de‐polarization, de‐residual and de‐background, as well as a non‐linear fitting algorithm are employed for the first time to calibrate the different CSM contribution of three typical cathode materials, LiFePO4, LiMn2O4 and Na4Fe3(PO4)2P2O7, and achieve well‐separated physical capacitance, pseudo‐capacitance and diffusive contributions to the total capacity. This work can eliminate misunderstanding concepts and correct ambiguous results of the pseudo‐capacitance contribution and recognize the essence of CSM in electrode materials.

Abstract Imine‐based covalent organic frameworks (COFs) are a widely studied class of functional, crystalline, and porous nanostructures which combine a relatively facile crystallization with tuneable compositions and porosities. However, the imine linkage constitutes an intrinsic limitation due to its reduced stability in harsh chemical conditions and its unsuitability for in‐plane π‐conjugation in COFs. Urgent solutions are therefore required in order to exploit the full potential of these materials, thereby enabling their technological application in electronics, sensing, and energy storage devices. In this context, the advent of a new generation of linkages derived from the chemical conversion and locking of the imine bond represents a cornerstone for the synthesis of new COFs. A marked increase in the framework robustness is in fact often combined with the incorporation of novel functionalities including, for some of these reactions, an extension of the in‐plane π‐conjugation. This Minireview describes the most enlightening examples of one‐pot reactions and post‐synthetic…

Abstract Porous materials with open metal sites have been investigated to separate various gas mixtures. However, open metal sites show the limitation in the separation of some challenging gas mixtures, such as C2H2/CO2. Herein, we propose a new type of ultra‐strong C2H2 nano‐trap based on multiple binding interactions to efficiently capture C2H2 molecules and separate C2H2/CO2 mixture. The ultra‐strong acetylene nano‐trap shows a benchmark Qst of 79.1 kJ mol−1 for C2H2, a record high pure C2H2 uptake of 2.54 mmol g−1 at 1×10−2 bar, and the highest C2H2/CO2 selectivity (53.6), making it as a new benchmark material for the capture of C2H2 and the separation of C2H2/CO2. The locations of C2H2 molecules within the MOF‐based nanotrap have been visualized by the in situ single‐crystal X‐ray diffraction studies, which also identify the multiple binding sites accountable for the strong interactions with C2H2.

Abstract Electrochemical production of hydrogen peroxide (H 2 O 2 ) through two‐electron (2 e − ) oxygen reduction reaction (ORR) is an on‐site and clean route. Oxygen‐doped carbon materials with high ORR activity and H 2 O 2 selectivity have been considered as the promising catalysts, however, there is still a lack of direct experimental evidence to identify true active sites at the complex carbon surface. Herein, we propose a chemical titration strategy to decipher the oxygen‐doped carbon nanosheet (OCNS 900 ) catalyst for 2 e − ORR. The OCNS 900 exhibits outstanding 2 e − ORR performances with onset potential of 0.825 V (vs. RHE), mass activity of 14.5 A g −1 at 0.75 V (vs. RHE) and H 2 O 2 production rate of 770 mmol g −1 h −1 in flow cell, surpassing most reported carbon catalysts. Through selective chemical titration of C=O, C−OH, and COOH groups, we found that C=O species contributed to the most electrocatalytic activity and were the most active sites for 2 e − ORR, which were corroborated by theoretical calculations.

Abstract Manganese‐based Prussian Blue, Na2−δMn[Fe(CN)6] (MnPB), is a good candidate for sodium‐ion battery cathode materials due to its high capacity. However, it suffers from severe capacity decay during battery cycling due to the destabilizing Jahn–Teller distortions it undergoes as Mn2+ is oxidized to Mn3+. Herein, the structure is stabilized by a thin epitaxial surface layer of nickel‐based Prussian Blue (Na2−δNi[Fe(CN)6]). The one‐pot synthesis relies on a chelating agent with an unequal affinity for Mn2+ and Ni2+ ions, which prevents Ni2+ from reacting until the Mn2+ is consumed. This is a new and simpler synthesis of core–shell materials, which usually needs several steps. The material has an electrochemical capacity of 93 mA h g−1, of which it retains 96 % after 500 charge–discharge cycles (vs. 37 % for MnPB). Its rate capability is also remarkable: at 4 A g−1 (ca. 55 C) it can reversibly store 70 mA h g−1, which is also reflected in its diffusion coefficient of ca. 10−8 cm2 s−1. The epitaxial outer layer appears to exert an anisotropic strain on the inner layer, preventing…

Abstract The electrocatalytic conversion of CO2 into value‐added chemicals is a promising approach to realize a carbon‐energy balance. However, low current density still limits the application of the CO2 electroreduction reaction (CO2RR). Metal–organic frameworks (MOFs) are one class of promising alternatives for the CO2RR due to their periodically arranged isolated metal active sites. However, the poor conductivity of traditional MOFs usually results in a low current density in CO2RR. We have prepared conductive two‐dimensional (2D) phthalocyanine‐based MOF (NiPc‐NiO4) nanosheets linked by nickel‐catecholate, which can be employed as highly efficient electrocatalysts for the CO2RR to CO. The obtained NiPc‐NiO4 has a good conductivity and exhibited a very high selectivity of 98.4 % toward CO production and a large CO partial current density of 34.5 mA cm−2, outperforming the reported MOF catalysts. This work highlights the potential of conductive crystalline frameworks in electrocatalysis.

Abstract Photocatalytic reduction of CO 2 to solar fuels and/or fine chemicals is a promising way to increase the energy supply and reduce greenhouse gas emissions. However, the conventional reaction system for CO 2 photoreduction with pure H 2 O or sacrificial agents usually suffers from low catalytic efficiency, poor stability, or cost‐ineffective atom economy. A recent surge of developments, in which photocatalytic CO 2 valorization is integrated with selective organic synthesis into one reaction system, indicates an efficient modus operandi that enables sufficient utilization of photogenerated electrons and holes to achieve the goals for sustainable economic and social development. In this Review we discuss current advances in cooperative photoredox reaction systems that integrate CO 2 valorization with organics upgrading based on heterogeneous photocatalysis. The applications and virtues of this strategy and the underlying reaction mechanisms are discussed. The ongoing challenges and prospects in this area are critically discussed.

Abstract The integration of Li2S6 within a poly(ethylene oxide) (PEO)‐based polymer electrolyte is demonstrated to improve the polymer electrolyte's ionic conductivity because the strong interplay between O2−(PEO) and Li+ from Li2S6 reduces the crystalline volume within the PEO. The Li/electrolyte interface is stabilized by the in situ formation of an ultra‐thin Li2S/Li2S2 layer via the reaction between Li2S6 and lithium metal, which increases the ionic transport at the interface and suppresses lithium dendrite growth. A symmetric Li/Li cell with the Li2S6‐integrated composite electrolyte has excellent cyclability and a high critical current density of 0.9 mA cm−2 at 40 °C. Impressive electrochemical performance is demonstrated with all‐solid‐state Li/LiFePO4 and high‐voltage Li/LiNi0.8Mn0.1Co0.1O2 cells at 40 °C.

Abstract The unique applications of porous metal–organic framework (MOF) liquids with permanent porosity and fluidity have attracted significant attention. However, fabrication of porous MOF liquids remains challenging because of the easy intermolecular self‐filling of the cavity or the rapid settlement of porous hosts in hindered solvents that cannot enter their pores. Herein, we report a facile strategy for the fabrication of a MOF liquid (Im‐UiO‐PL) by surface ionization of an imidazolium‐functionalized framework with a sterically hindered poly(ethylene glycol) sulfonate (PEGS) canopy. The Im‐UiO‐PL obtained in this way has a CO 2 adsorption approximately 14 times larger than that of pure PEGS. Distinct from a porous MOF solid counterpart, the stored CO 2 in Im‐UiO‐PL can be slowly released and efficiently utilized to synthesize cyclic carbonates in the atmosphere. This is the first example of the use of a porous MOF liquid as a CO 2 storage material for catalysis. It offers a new method for the fabrication of unique porous liquid MOFs with functional behaviors in various fields…

Abstract Aqueous ammonium‐ion (NH4+) batteries (AAIB) are a recently emerging technology that utilize the abundant electrode resources and the fast diffusion kinetics of NH4+ to deliver an excellent rate performance at a low cost. Although significant progress has been made on AAIBs, the technology is still limited by various challenges. In this Minireview, the most recent advances are comprehensively summarized and discussed, including cathode and anode materials as well as the electrolytes. Finally, a perspective on possible solutions for the current limitations of AAIBs is provided.

Abstract Layered double hydroxides (LDHs) are among the most active and studied catalysts for the oxygen evolution reaction (OER) in alkaline electrolytes. However, previous studies have generally either focused on a small number of LDHs, applied synthetic routes with limited structural control, or used non‐intrinsic activity metrics, thus hampering the construction of consistent structure–activity‐relations. Herein, by employing new individually developed synthesis strategies with atomic structural control, we obtained a broad series of crystalline α‐MA(II)MB(III) LDH and β‐MA(OH)2 electrocatalysts (MA=Ni, Co, and MB=Co, Fe, Mn). We further derived their intrinsic activity through electrochemical active surface area normalization, yielding the trend NiFe LDH > CoFe LDH > Fe‐free Co‐containing catalysts > Fe‐Co‐free Ni‐based catalysts. Our theoretical reactivity analysis revealed that these intrinsic activity trends originate from the dual‐metal‐site nature of the reaction centers, which lead to composition‐dependent synergies and diverse scaling relationships that may be used to…

Abstract Light‐emitting chiral carbonized polymer dots (Ch‐CPDs) are attracting great interest because of their extraordinary photonic properties, but modulating their band‐gap emission, especially at long wavelength, and maintaining their chiral structure to achieve multicolor, high‐emission Ch‐CPDs remains challenging. Reported here for the first time is the synthesis of red‐ and multicolor‐emitting Ch‐CPDs using the common precursors L ‐/ D ‐tryptophan and o ‐phenylenediamine, and a solvothermal approach at one temperature. The quantum yield of the Ch‐CPDs was between 31 % and 54 %. Supramolecular self‐assembly provided multicolor‐emitting Ch‐CPDs showing novel circularly polarized luminescence, with the highest dissymmetric factor (g lum ) of 1×10 −2 . Importantly, circularly polarized white‐emitting CPDs were fabricated for the first time by tuning the mixing ratio of the three colored Ch‐CPDs in a gel. This strategy affords exciting opportunities for designing functional chiroptical materials.

Abstract Electrochemical reduction of CO 2 (CO 2 RR) into valuable hydrocarbons is appealing in alleviating the excessive CO 2 level. We present the very first utilization of metallic bismuth–tin (Bi‐Sn) aerogel for CO 2 RR with selective HCOOH production. A non‐precious bimetallic aerogel of Bi‐Sn is readily prepared at ambient temperature, which exhibits 3D morphology with interconnected channels, abundant interfaces and a hydrophilic surface. Superior to Bi and Sn, the Bi‐Sn aerogel exposes more active sites and it has favorable mass transfer properties, which endow it with a high FE HCOOH of 93.9 %. Moreover, the Bi‐Sn aerogel achieves a FE HCOOH of ca. 90 % that was maintained for 10 h in a flow battery. In situ ATR‐FTIR measurements confirmed that the formation of *HCOO is the rate‐determining step toward formic acid generation. DFT demonstrated the coexistence of Bi and Sn optimized the energy barrier for the production of HCOOH, thereby improving the catalytic activity.

Abstract The application of traditional electrode materials for high‐performance capacitive deionization (CDI) has been persistently limited by their low charge‐storage capacities, excessive co‐ion expulsion and slow salt removal rates. Here we report a bottom‐up approach to the preparation of a two‐dimensional (2D) Ti 3 C 2 T x MXene‐polydopamine heterostructure having ordered in‐plane mesochannels (denoted as mPDA/MXene). Interfacial self‐assembly of mesoporous polydopamine (mPDA) monolayers on MXene nanosheets leads to the mPDA/MXene heterostructure, which exhibits several unique features: (1) MXene undergoes reversible ion intercalation/deintercalation and possesses high conductivity; (2) mPDA layers establish redox capacitive characteristics and Na + selectivity, and also help to prevent self‐stacking and oxidation of MXene; (3) in‐plane mesochannels enable the smooth transport of ions at the internal spaces of this stacked 2D material. When applied as an electrode material for CDI, mPDA/MXene nanosheets exhibit top‐level CDI performance and cycling stability compared to those…

Abstract Electrochemical reduction of NO not only offers an attractive alternative to the Haber–Bosch process for ambient NH3 production but mitigates the human‐caused unbalance of nitrogen cycle. Herein, we report that MoS2 nanosheet on graphite felt (MoS2/GF) acts as an efficient and robust 3D electrocatalyst for NO‐to‐NH3 conversion. In acidic electrolyte, such MoS2/GF attains a maximal Faradaic efficiency of 76.6 % and a large NH3 yield of up to 99.6 μmol cm−2 h−1. Using MoS2 nanosheet‐loaded carbon paper as the cathode, a proof‐of‐concept device of Zn‐NO battery was assembled to deliver a discharge power density of 1.04 mW cm−2 and an NH3 yield of 411.8 μg h−1 mgcat.−1. Calculations reveal that the positively charged Mo‐edge sites facilitate NO adsorption/activation via an acceptance–donation mechanism and disfavor the binding of protons and the coupling of N−N bond.

Abstract Cu‐based electrocatalysts facilitate CO2 electrochemical reduction (CO2ER) to produce multi‐carbon products. However, the roles of Cu0 and Cu+ and the mechanistic understanding remain elusive. This paper describes the controllable construction of Cu0‐Cu+ sites derived from the well‐dispersed cupric oxide particles supported on copper phyllosilicate lamella to enhance CO2ER performance. 20 % Cu/CuSiO3 shows the superior CO2ER performance with 51.8 % C2H4 Faraday efficiency at −1.1 V vs reversible hydrogen electrode during the 6 hour test. In situ attenuated total reflection infrared spectra and density functional theory (DFT) calculations were employed to elucidate the reaction mechanism. The enhancement in CO2ER activity is mainly attributed to the synergism of Cu0‐Cu+ pairs: Cu0 activates CO2 and facilitates the following electron transfers; Cu+ strengthens *CO adsorption to further boost C−C coupling. We provide a strategy to rationally design Cu‐based catalysts with viable valence states to boost CO2ER.

Abstract Aqueous Zn‐ion batteries (ZIBs) are regarded as alternatives to Li‐ion batteries benefiting from both improved safety and environmental impact. The widespread application of ZIBs, however, is compromised by the lack of high‐performance cathodes. Currently, only the intercalation mechanism is widely reported in aqueous ZIBs, which significantly limits cathode options. Beyond Zn‐ion intercalation, we comprehensively study the conversion mechanism for Zn 2+ storage and its diffusion pathway in a CuI cathode, indicating that CuI occurs a direct conversion reaction without Zn 2+ intercalation due to the high energy barrier for Zn 2+ intercalation and migration. Importantly, this direct conversion reaction mechanism can be readily generalized to other high‐capacity cathodes, such as Cu 2 S (336.7 mA h g −1 ) and Cu 2 O (374.5 mA h g −1 ), indicating its practical universality. Our work enriches the Zn‐ion storage mechanism and significantly broadens the cathode horizons towards next‐generation ZIBs.

Abstract Herein, an effective tandem catalysis strategy is developed to improve the selectivity of the CO 2 RR towards C 2 H 4 by multiple distinct catalytic sites in local vicinity. An earth‐abundant elements‐based tandem electrocatalyst PTF(Ni)/Cu is constructed by uniformly dispersing Cu nanoparticles (NPs) on the porphyrinic triazine framework anchored with atomically isolated nickel–nitrogen sites (PTF(Ni)) for the enhanced CO 2 RR to produce C 2 H 4 . The Faradaic efficiency of C 2 H 4 reaches 57.3 % at −1.1 V versus the reversible hydrogen electrode (RHE), which is about 6 times higher than the non‐tandem catalyst PTF/Cu, which produces CH 4 as the major carbon product. The operando infrared spectroscopy and theoretic density functional theory (DFT) calculations reveal that the local high concentration of CO generated by PTF(Ni) sites can facilitate the C−C coupling to form C 2 H 4 on the nearby Cu NP sites. The work offers an effective avenue to design electrocatalysts for the highly selective CO 2 RR to produce multicarbon products via a tandem route.

Abstract Iodine vacancies (VI) and undercoordinated Pb2+ on the surface of all‐inorganic perovskite films are mainly responsible for nonradiative charge recombination. An environmentally benign material, histamine (HA), is used to passivate the VI in perovskite films. A theoretical study shows that HA bonds to the VI on the surface of the perovskite film via a Lewis base–acid interaction; an additional hydrogen bond (H‐bond) strengthens such interaction owing to the favorable molecular configuration of HA. Undercoordinated Pb2+ and Pb clusters are passivated, leading to significantly reduced surface trap density and prolonged charge lifetime within the perovskite films. HA passivation also induces an upward shift of the energy band edge of the perovskite layer, facilitating interfacial hole transfer. The combination of the above raises the solar cell efficiency from 19.5 to 20.8 % under 100 mW cm−2 illumination, the highest efficiency so far for inorganic metal halide perovskite solar cells (PSCs).

Abstract Metal–organic frameworks (MOFs) with carboxylate ligands as co‐catalysts are very efficient for the oxygen evolution reaction (OER). However, the role of local adsorbed carboxylate ligands around the in‐situ‐transformed metal (oxy)hydroxides during OER is often overlooked. We reveal the extraordinary role and mechanism of surface‐adsorbed carboxylate ligands on bi/trimetallic layered double hydroxides (LDHs)/MOFs for OER electrocatalytic activity enhancement. The results of X‐ray photoelectron spectroscopy (XPS), synchrotron X‐ray absorption spectroscopy, and density functional theory (DFT) calculations show that the carboxylic groups around metal (oxy)hydroxides can efficiently induce interfacial electron redistribution, facilitate an abundant high‐valence state of nickel species with a partially distorted octahedral structure, and optimize the d‐band center together with the beneficial Gibbs free energy of the intermediate. Furthermore, the results of in situ Raman and FTIR spectra reveal that the surface‐adsorbed carboxylate ligands as Lewis base can promote sluggish OER…

Abstract Metallene with fantastic physicochemical properties is considered as a potential candidate for oxygen reduction reaction (ORR). Controlling the morphology and structure of metallene can provide a great opportunity to improve its catalytic performance. Herein, defect‐rich ultrathin porous Pd metallene (a sub‐nanometer and curved metal nanosheet) is developed by facile wet‐chemistry strategy for efficient and stable ORR electrocatalysis in alkaline electrolyte. The defect‐rich porous Pd metallene provides abundant highly active sites and vacancy defects, showing superior ORR activity of 0.892 A mgPd−1 at 0.9 V vs. the reversible hydrogen electrode. The mass activity is 5.1 and 16.8 times higher than those of commercial Pt/C and Pd/C, respectively, and maintains well after 5000 cycles. The strain effect and tunable electronic structure derived from highly curved sub‐nanometer nanosheet morphology contribute to the excellent ORR performance by the optimization of oxygen binding ability on Pd. The superior catalytic performance of Pd metallene may open an avenue to design other…

Abstract Integrating biomass upgrading and hydrogen production in an electrocatalytic system is attractive both environmentally and in terms of sustainability. Conventional electrolyser systems coupling anodic biosubstrate electrooxidation with hydrogen evolution reaction usually require electricity input. Herein, we describe the development of an electrocatalytic system for simultaneous biomass upgrading, hydrogen production, and electricity generation. In contrast to conventional furfural electrooxidation, the employed low‐potential furfural oxidation enabled the hydrogen atom of the aldehyde group to be released as gaseous hydrogen at the anode at a low potential of approximately 0 VRHE (vs. RHE). The integrated electrocatalytic system could generate electricity of about 2 kWh per cubic meter of hydrogen produced. This study may provide a transformative technology to convert electrocatalytic biomass upgrading and hydrogen production from a process requiring electricity input into a process to generate electricity.

Abstract Spinel zinc cobalt oxide (ZnCo 2 O 4 ) is not considered as a superior catalyst for the electrochemical oxygen evolution reaction (OER), which is the bottleneck reaction in water‐electrolysis. Herein, taking advantage of density functional theory (DFT) calculations, we find that the existence of low‐spin (LS) state cobalt cations hinders the OER activity of spinel zinc cobalt oxide, as the t 2g 6 e g 0 configuration gives rise to purely localized electronic structure and exhibits poor binding affinity to the key reaction intermediate. Increasing the spin state of cobalt cations in spinel ZnCo 2 O 4 is found to propagate a spin channel to promote spin‐selected charge transport during OER and generate better active sites for intermediates adsorption. The experiments find increasing the calcination temperature a facile approach to engineer high‐spin (HS) state cobalt cations in ZnCo 2 O 4 , while not working for Co 3 O 4 . The activity of the best spin‐state‐engineered ZnCo 2 O 4 outperforms other typical Co‐based oxides.

Abstract Electrochemical CO 2 reduction reaction (CO 2 RR) to multicarbon hydrocarbon and oxygenate (C 2+ ) products with high energy density and wide availability is of great importance, as it provides a promising way to achieve the renewable energy storage and close the carbon cycle. Herein we design a Cu‐CuI composite catalyst with abundant Cu 0 /Cu + interfaces by physically mixing Cu nanoparticles and CuI powders. The composite catalyst achieves a remarkable C 2+ partial current density of 591 mA cm −2 at −1.0 V vs. reversible hydrogen electrode in a flow cell, substantially higher than Cu (329 mA cm −2 ) and CuI (96 mA cm −2 ) counterparts. Induced by alkaline electrolyte and applied potential, the Cu‐CuI composite catalyst undergoes significant reconstruction under CO 2 RR conditions. The high‐rate C 2+ production over Cu‐CuI is ascribed to the presence of residual Cu + and adsorbed iodine species which improve CO adsorption and facilitate C−C coupling.

Abstract The development of efficient and low‐cost electrocatalysts toward the oxygen evolution reaction (OER) is critical for improving the efficiency of several electrochemical energy conversion and storage devices. Here, we report an elaborate design and synthesis of porous Co‐based trimetallic spinel oxide nanoboxes (NiCo 2− x Fe x O 4 NBs) by a novel metal‐organic framework engaged strategy, which involves chemical etching, cation exchange, and subsequent thermal oxidation processes. Owing to the structural and compositional advantages, the optimized trimetallic NiCo 2− x Fe x O 4 NBs ( x is about 0.117) deliver superior electrocatalytic performance for OER with an overpotential of 274 mV at 10 mA cm −2 , a small Tafel slope of 42 mV dec −1 , and good stability in alkaline electrolyte, which is much better than that of Co‐based bi/monometallic spinel oxides and even commercial RuO 2 .

Abstract Owing to their unique electronic structure and maximum atom utilization efficiency, single‐atom catalysts have received widespread attention and exhibited efficient activity. Herein, we report the preparation of non‐metal Se single atoms embedded in nitrogen‐doped carbon (NC) via a high‐temperature reduction strategy for electrocatalytic oxygen reduction reaction (ORR). Selenium dioxide is reduced to selenium by NC at high temperature and partially anchored to form C−Se−C bond. Impressively, the obtained single‐atom catalyst exhibits outstanding ORR activity and stability that even surpasses state‐of‐the‐art noble metal catalysts and many previously reported nanocatalysts. Experimental and theoretical calculations reveal that the Se single atoms can serve as the ORR active sites and contribute to lowering the reaction barrier. Our discoveries demonstrate the promising prospects for utilizing metal‐free single‐atom‐based materials for efficient electrocatalysis.

Abstract Given the limitations inherent in current intercalation‐based Li‐ion batteries, much research attention has focused on potential successors to Li‐ion batteries such as lithium–sulfur (Li‐S) batteries and lithium–oxygen (Li‐O2) batteries. In order to realize the potential of these batteries, the use of metallic lithium as the anode is essential. However, there are severe safety hazards associated with the growth of Li dendrites, and the formation of “dead Li” during cycles leads to the inevitable loss of active Li, which in the end is undoubtedly detrimental to the actual energy density of Li‐metal batteries. For Li‐metal batteries under practical conditions, a low negative/positive ratio (N/P ratio), a electrolyte/cathode ratio (E/C ratio) along with a high‐voltage cathode is prerequisite. In this Review, we summarize the development of new electrolyte systems for Li‐metal batteries under practical conditions, revisit the design criteria of advanced electrolytes for practical Li‐metal batteries and provide perspectives on future development of electrolytes for practical…

Abstract Organic solar cells (OSCs) with nonfullerene acceptors (NFAs) exhibit efficient charge generation under small interfacial energy offsets, leading to over 18 % efficiency for the single‐junction devices based on the state‐of‐the‐art NFA of Y6. Herein, to reveal the underlying charge generation mechanisms, we have investigated the exciton binding energy (Eb) in Y6 by a joint theoretical and experimental study. The results show that owing to strong charge polarization effects, Y6 has remarkable small Eb of −0.11–0.15 eV, which is even lower than perovskites in many cases. Moreover, it is peculiar that the photoluminescence is enhanced with temperature, and the energy barrier for separating excitons into charges is evidently lower than the thermal energy according to the temperature dependence of photoluminescence, manifesting direct photogeneration of charge carriers enabled by weak Eb in Y6. Thus, charge generation in NFA‐based OSCs shows little dependence on interfacial driving forces.

Abstract Dual‐atom site catalysts (DACs) have emerged as a new frontier in heterogeneous catalysis because the synergistic effect between adjacent metal atoms can promote their catalytic activity while maintaining the advantages of single‐atom site catalysts (SACs), like 100 % atomic utilization efficiency and excellent selectivity. Herein, a supported Pd2DAC was synthesized and used for electrochemical CO2reduction reaction (CO2RR) for the first time. The as‐obtained Pd2DAC exhibited superior CO2RR catalytic performance with 98.2 % CO faradic efficiency at −0.85 V vs. RHE, far exceeding that of Pd1SAC, and coupled with long‐term stability. The density functional theory (DFT) calculations revealed that the intrinsic reason for the superior activity of Pd2DAC toward CO2RR was the electron transfer between Pd atoms at the dimeric Pd sites. Thus, Pd2DAC possessed moderate adsorption strength of CO*, which was beneficial for CO production in CO2RR.

Abstract Theoretical calculations unveil the charge redistribution over abundant interfaces and the enhanced electronic states of Ru/RuS2heterostructure. The resulting surface electron‐deficient Ru sites display optimized adsorption behavior toward diverse reaction intermediates, thereby reducing the thermodynamic energy barriers. Experimentally, for the first time the laminar Ru/RuS2heterostructure is rationally engineered by virtue of the synchronous reduction and sulfurization under eutectic salt system. Impressively, it exhibits extremely high catalytic activity for both OER (201 mV @ 10 mA cm−2) and HER (45 mV @ 10 mA cm−2) in acidic media due to favorable kinetics and excellent specific activity, consequently leading to a terrific performance in acidic overall water splitting devices (1.501 V @ 10 mA cm−2). The in‐depth insight into the internal activity origin of interfacial effect could offer precise guidance for the rational establishment of hybrid interfaces.

Abstract Developing organic luminophores with unique capability of strong narrowband emission is both crucial and challenging for the further advancement of organic light‐emitting diodes (OLEDs). Herein, a nanographitic fused‐nonacyclic π‐system ( BSBS‐N1 ), which was strategically embedded with multiple boron, nitrogen, and sulfur atoms, was developed as a new multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitter. Narrowband sky‐blue emission with a peak at 478 nm, full width at half maximum of 24 nm, and photoluminescence quantum yield of 89 % was obtained with BSBS‐N1 . Additionally, the spin‐orbit coupling was enhanced by incorporating two sulfur atoms, thereby facilitating the spin‐flipping process between the excited triplet and singlet states. OLEDs based on BSBS‐N1 as a sky‐blue MR‐TADF emitter achieved a high maximum external electroluminescence quantum efficiency of 21.0 %, with improved efficiency roll‐off.

Abstract Emerging machine learning (ML) methods are widely applied in chemistry and materials science studies and have led to a focus on data‐driven research. This Minireview summarizes the application of ML to rechargeable batteries, from the microscale to the macroscale. Specifically, ML offers a strategy to explore new functionals for density functional theory calculations and new potentials for molecular dynamics simulations, which are expected to significantly enhance the challenging descriptions of interfaces and amorphous structures. ML also possesses a great potential to mine and unveil valuable information from both experimental and theoretical datasets. A quantitative “structure–function” correlation can thus be established, which can be used to predict the ionic conductivity of solids as well as the battery lifespan. ML also exhibits great advantages in strategy optimization, such as fast‐charge procedures. The future combination of multiscale simulations, experiments, and ML is also discussed and the role of humans in data‐driven research is highlighted.

Abstract Separation of acetylene from carbon dioxide remains a daunting challenge because of their very similar molecular sizes and physical properties. We herein report the first example of using copper(I)‐alkynyl chemistry within an ultra‐microporous MOF (CuI@UiO‐66‐(COOH)2) to achieve ultrahigh C2H2/CO2separation selectivity. The anchored CuIions on the pore surfaces can specifically and strongly interact with C2H2molecule through copper(I)‐alkynyl π‐complexation and thus rapidly adsorb large amount of C2H2at low‐pressure region, while effectively reduce CO2uptake due to the small pore sizes. This material thus exhibits the record high C2H2/CO2selectivity of 185 at ambient conditions, significantly higher than the previous benchmark ZJU‐74a (36.5) and ATC‐Cu (53.6). Theoretical calculations reveal that the unique π‐complexation between CuIand C2H2mainly contributes to the ultra‐strong C2H2binding affinity and record selectivity. The exceptional separation performance was evidenced by breakthrough experiments for C2H2/CO2gas mixtures. This work suggests a new perspective to…

Abstract We report the development of a highly sensitive ratiometric fluorescent lateral flow immunoassay (RFLFIA) strip for rapid and accurate detection of acute myocardial infarction biomarker, namely heart‐type fatty acid binding protein (H‐FABP). The RFLFIA strip works in terms of ratiometric change of fluorescence signal, arising from blending of fluorescence emitted by two composite nanostructures conjugated to capture and probe antibodies and inner filter effect of gold nanoparticles. In conjunction with using custom smartphone‐based analytical device and tonality analysis, quantitative detection of H‐FABP was achieved with a low limit of detection at 0.21 ng mL −1 . The RFLFIA strip can generate a visually distinguishable green‐to‐red color change around the threshold concentration of H‐FABP (6.2 ng mL −1 ), thus allowing the semi‐quantitative diagnosis by the naked eye.

Abstract Anion‐exchange membrane fuel cells (AEMFCs) are a promising, next‐generation fuel cell technology. AEMFCs require highly conductive and robust anion‐exchange membranes (AEMs), which are challenging to develop due to the tradeoff between conductivity and water uptake. Here we report a method to prepare high‐molecular‐weight branched poly(aryl piperidinium) AEMs. We show that branching reduces water uptake, leading to improved dimensional stability. The optimized membrane, b‐PTP‐2.5, exhibits simultaneously high OH − conductivity (>145 mS cm −1 at 80 °C), high mechanical strength and dimensional stability, good processability, and excellent alkaline stability (>1500 h) in 1 M KOH at 80 °C. AEMFCs based on b‐PTP‐2.5 reached peak power densities of 2.3 W cm −2 in H 2 −O 2 and 1.3 W cm −2 in H 2 ‐air at 80 °C. The AEMFCs can run stably under a constant current of 0.2 A cm −2 over 500 h, during which the b‐PTP‐2.5 membrane remains stable.

Abstract Bottom‐up synthetic biology is the science of building systems that mimic the structure and function of living cells from scratch. To do this, researchers combine tools from chemistry, materials science, and biochemistry to develop functional and structural building blocks to construct synthetic cell‐like systems. The many strategies and materials that have been developed in recent decades have enabled scientists to engineer synthetic cells and organelles that mimic the essential functions and behaviors of natural cells. Examples include synthetic cells that can synthesize their own ATP using light, maintain metabolic reactions through enzymatic networks, perform gene replication, and even grow and divide. In this Review, we discuss recent developments in the design and construction of synthetic cells and organelles using the bottom‐up approach. Our goal is to present representative synthetic cells of increasing complexity as well as strategies for solving distinct challenges in bottom‐up synthetic biology.

Abstract Studying structure–activity correlations of electrocatalysts is essential for improving the conversion of electrical to chemical energy. Recently, increasing evidence obtained by operando characterization techniques reveal that the structural evolution of catalysts caused by the interplay with electric fields, electrolytes and reactants/intermediates brings about the formation of real active sites. Hence, it is time to summarize structural evolution related research advances and envisage future developments. In this Minireview, we first introduce the fundamental concepts associated with structural evolution (e.g., catalysts, active sites/centers and stability/lifetime) and their relevance. Then, the multiple triggers of structural evolution and advanced operando characterizations are discussed. Significantly, a brief overview of structural evolution and its reversibility in heterogeneous electrocatalysis is provided, especially for the representative electrocatalytic oxygen evolution reaction (OER) and CO2 reduction reaction (CO2RR) processes. Lastly, key challenges and…

Abstract When the stakes are doubled in a wager, a player must correctly place two consecutive bets to win, but the payout is larger. Similarly, two B sites in combination dictate the properties of A2BB′X6 (A=monocation, X=halide) double perovskites. Correctly picking two B sites is more challenging than picking just one, as in the AIBIIX3 single perovskites, but the options are greater and, we believe, the rewards are higher when the stakes are doubled. In this Minireview, we emphasize fundamental aspects of halide double perovskites to provide a foundation for interested readers to explore this extraordinary class of materials. In particular, we highlight the differences and similarities between double and single perovskites and describe how the double perovskite structure potentially offers greater control over photophysical properties.

Abstract Electrocatalytic denitrification is a promising technology for removing NOx species (NO3−, NO2− and NO). For NOx electroreduction (NOxRR), there is a desire for understanding the catalytic parameters that control the product distribution. Here, we elucidate selectivity and activity of catalyst for NOxRR. At low potential we classify metals by the binding of *NO versus *H. Analogous to classifying CO2 reduction by *CO vs. *H, Cu is able to bind *NO while not binding *H giving rise to a selective NH3 formation. Besides being selective, Cu is active for the reaction found by an activity‐volcano. For metals that does not bind NO the reaction stops at NO, similar to CO2‐to‐CO. At potential above 0.3 V vs. RHE, we speculate a low barrier for N coupling with NO causing N2O formation. The work provides a clear strategy for selectivity and aims to inspire future research on NOxRR.

Abstract The catalytic performance of composite catalysts is not only affected by the physicochemical properties of each component, but also the proximity and interaction between them. Herein, we employ four representative oxides (In 2 O 3 , ZnO, Cr 2 O 3 , and ZrO 2 ) to combine with H‐ZSM‐5 for the hydrogenation of CO 2 to hydrocarbons directed by methanol intermediate and clarify the correlation between metal migration and the catalytic performance. The migration of metals to zeolite driven by the harsh reaction conditions can be visualized by electron microscopy, meanwhile, the change of zeolite acidity is also carefully characterized. The protonic sites of H‐ZSM‐5 are neutralized by mobile indium and zinc species via a solid ion‐exchange mechanism, resulting in a drastic decrease of C 2+ hydrocarbon products over In 2 O 3 /H‐ZSM‐5 and ZnO/H‐ZSM‐5. While, the thermomigration ability of chromium and zirconium species is not significant, endowing Cr 2 O 3 /H‐ZSM‐5 and ZrO 2 /H‐ZSM‐5 catalysts with high selectivity of C 2+ hydrocarbons.

Abstract NiFe‐layered double hydroxides (NiFe‐LDH) are among the most active catalysts developed to date for the oxygen evolution reaction (OER) in alkaline media, though their long‐term OER stability remains unsatisfactory. Herein, we reveal that the stability degradation of NiFe‐LDH catalysts during alkaline OER results from a decreased number of active sites and undesirable phase segregation to form NiOOH and FeOOH, with metal dissolution underpinning both of these deactivation mechanisms. Further, we demonstrate that the introduction of cation‐vacancies in the basal plane of NiFe LDH is an effective approach for achieving both high catalyst activity and stability during OER. The strengthened binding energy between the metals and oxygen in the LDH sheets, together with reduced lattice distortions, both realized by the rational introduction of cation vacancies, drastically mitigate metal dissolution from NiFe‐LDH under high oxidation potentials, resulting in the improved long‐term OER stability. In addition, the cation vacancies (especially M 3+ vacancies) accelerate the evolution…

Abstract Owing to their superior thermal stability, metal halide inorganic perovskite materials continue to attract interest for photovoltaics applications. The highest reported power conversion efficiency (PCE) for solar cells based on inorganic perovskites is over 20 %. As this PCE corresponds to 73 % of the theoretical limit, there remains more room for further improving the device PCEs than for improving organic–inorganic hybrid perovskite solar cells (PSCs). The main loss is in the photovoltage, which is limited by interfaces in terms of non‐radiative recombination caused by traps and energy‐level mismatch. Furthermore, inefficient charge extraction at interfacial contacts reduces the photocurrent and fill factor. This Minireview summarizes the recent developments in the fundamental understanding of how the interfaces and interfacial layers influence the performance of solar cells based on inorganic perovskite absorbers. An outlook for the development of highly efficient and stable inorganic PSCs from the interface point of view is also given.

Abstract Electrocatalysts play a key role in accelerating the sluggish electrochemical CO 2 reduction (ECR) involving multi‐electron and proton transfer. We now develop a proton capture strategy by accelerating the water dissociation reaction catalyzed by transition‐metal nanoparticles (NPs) adjacent to atomically dispersed and nitrogen‐coordinated single nickel (Ni−N x ) active sites to accelerate proton transfer to the latter for boosting the intermediate protonation step, and thus the whole ECR process. Aberration‐corrected scanning transmission electron microscopy, X‐ray absorption spectroscopy, and calculations reveal that the Ni NPs accelerate the adsorbed H (H ad ) generation and transfer to the adjacent Ni−N x sites for boosting the intermediate protonation and the overall ECR processes. This proton capture strategy is universal to design and prepare for various high‐performance catalysts for diverse electrochemical reactions even beyond ECR.

Abstract Oxidative cleavage of C(OH)−C bonds to afford carboxylates is of significant importance for the petrochemical industry and biomass valorization. Here we report an efficient electrochemical strategy for the selective upgrading of lignin derivatives to carboxylates by a manganese‐doped cobalt oxyhydroxide (MnCoOOH) catalyst. A wide range of lignin‐derived substrates with C(OH)‐C or C(O)‐C units undergo efficient cleavage to corresponding carboxylates in excellent yields (80–99 %) and operational stability (200 h). Detailed investigations reveal a tandem oxidation mechanism that base from the electrolyte converts secondary alcohols and their derived ketones to reactive nucleophiles, which are oxidized by electrophilic oxygen species on MnCoOOH from water. As proof of concept, this approach was applied to upgrade lignin derivatives with C(OH)‐C or C(O)‐C motifs, achieving convergent transformation of lignin‐derived mixtures to benzoate and KA oil to adipate with 91.5 % and 64.2 % yields, respectively.

Abstract The co‐insertion of dual ions can often offer enhanced electrochemical performance for the aqueous zinc batteries. Although the insertion of non‐metallic ions has been achieved in aqueous zinc batteries, the co‐insertion chemistry of non‐metallic cations is still a challenge. Here, a reversible H + /NH 4 + co‐insertion/extraction mechanism was developed in an aqueous Zn/MnO 2 battery system. The synergistic effect between the dual cations endows the aqueous batteries with the fast kinetics of ion diffusion and the reversible structure evolution of MnO 2 . As a result, the Zn/MnO 2 battery displays excellent rate capability and cycling performance. This work will pave the way toward the design of aqueous rechargeable batteries with non‐metallic ions.

Abstract Ruthenium (Ru)‐based catalysts, with considerable performance and desirable cost, are becoming highly interesting candidates to replace platinum (Pt) in the alkaline hydrogen evolution reaction (HER). The hydrogen binding at Ru sites (Ru−H) is an important factor limiting the HER activity. Herein, density functional theory (DFT) simulations show that the essence of Ru−H binding energy is the strong interaction between the orbital of Ru and the 1s orbital of H. The charge transfer between Ru sites and substrates (Co and Ni) causes the appropriate downward shift of the ‐band center of Ru, which results in a Gibbs free energy of 0.022 eV for H* in the RuCo system, much lower than the 0.133 eV in the pure Ru system. This theoretical prediction has been experimentally confirmed using RuCo alloy‐nanosheets (RuCo ANSs). They were prepared via a fast co‐precipitation method followed with a mild electrochemical reduction. Structure characterizations reveal that the Ru atoms are embedded into the Co substrate as isolated active sites with a planar symmetric and Z‐direction asymmetric…

Abstract Multiple resonance (MR) emitters are promising for highly efficient organic light‐emitting diodes (OLEDs) with narrowband emission; however, they still face intractable challenges with concentration‐caused emission quenching, exciton annihilation, and spectral broadening. In this study, sterically wrapped MR dopants with a fluorescent MR core sandwiched by bulk substituents were developed to address the intractable challenges by reducing intermolecular interactions. Consequently, high photo‐luminance quantum yields of ≥90 % and small full width at half maximums (FWHMs) of ≤25 nm over a wide range of dopant concentrations (1–20 wt %) were recorded. In addition, we demonstrated that the sandwiched MR emitter can effectively suppress Dexter interaction when doped in a thermally activated delayed fluorescence sensitizer, eliminating exciton loss through dopant triplet. Within the above dopant concentration range, the optimal emitter realizes remarkably high maximum external quantum efficiencies of 36.3–37.2 %, identical small FWHMs of 24 nm, and alleviated efficiency roll‐offs…

Abstract Urea electrolysis is a prospective technology for simultaneous H2 production and nitrogen suppression in the process of water being used for energy production. Its sustainability is currently founded on innocuous N2 products; however, we discovered that prevalent nickel‐based catalysts could generally over‐oxidize urea into NO2− products with ≈80 % Faradaic efficiencies, posing potential secondary hazards to the environment. Trace amounts of over‐oxidized NO3− and N2O were also detected. Using 15N isotopes and urea analogues, we derived a nitrogen‐fate network involving a NO2−‐formation pathway via OH−‐assisted C−N cleavage and two N2‐formation pathways via intra‐ and intermolecular coupling. DFT calculations confirmed that C−N cleavage is energetically more favorable. Inspired by the mechanism, a polyaniline‐coating strategy was developed to locally enrich urea for increasing N2 production by a factor of two. These findings provide complementary insights into the nitrogen fate in water–energy nexus systems.

Abstract Molecular activatable probes with near‐infrared (NIR) fluorescence play a critical role in in vivo imaging of biomarkers for drug screening and disease diagnosis. With structural diversity and high fluorescence quantum yields, hemicyanine dyes have emerged as a versatile scaffold for the construction of activatable optical probes. This Review presents a survey of hemicyanine‐based NIR activatable probes (HNAPs) for in vivo imaging and early diagnosis of diseases. The molecular design principles of HNAPs towards activatable optical signaling against various biomarkers are discussed with a focus on their broad applications in the detection of diseases including inflammation, acute organ failure, skin diseases, intestinal diseases, and cancer. This progress not only proves the unique value of HNAPs in preclinical research but also highlights their high translational potential in clinical diagnosis.

Abstract A universal strategy is developed to construct a cascade Z‐Scheme system, in which an effective energy platform is the core to direct charge transfer and separation, blocking the unexpected type‐II charge transfer pathway. The dimension‐matched (001)TiO2‐g‐C3N4/BiVO4 nanosheet heterojunction (T‐CN/BVNS) is the first such model. The optimized cascade Z‐Scheme exhibits ≈19‐fold photoactivity improvement for CO2 reduction to CO in the absence of cocatalysts and costly sacrificial agents under visible‐light irradiation, compared with BVNS, which is also superior to other reported Z‐Scheme systems even with noble metals as mediators. The experimental results and DFT calculations based on van der Waals structural models on the ultrafast timescale reveal that the introduced T as the platform prolongs the lifetimes of spatially separated electrons and holes and does not compromise their reduction and oxidation potentials.

Abstract Herein, we reported an ultrapure blue multiple‐resonance‐induced thermally activated delayed fluorescence (MR‐TADF) material (ν‐DABNA‐O‐Me) with a high photoluminescence quantum yield and a large rate constant for reverse intersystem crossing. Because of restricted π‐conjugation of the HOMO rather than the LUMO induced by oxygen atom incorporation, ν‐DABNA‐O‐Me shows a hypsochromic shift compared to the parent MR‐TADF material (ν‐DABNA). An organic light‐emitting diode based on this material exhibits an emission at 465 nm, with a small full‐width at half‐maximum of 23 nm and Commission Internationale de l'Eclairage coordinates of (0.13, 0.10), and a high maximum external quantum efficiency of 29.5 %. Moreover, ν‐DABNA‐O‐Me facilitates a drastically improved efficiency roll‐off and a device lifetime compared to ν‐DABNA, which demonstrates significant potential of the oxygen atom incorporation strategy.

Abstract The use of organic photocatalysts has revolutionized the field of photoredox catalysis, as it allows access to reactivities that were traditionally restricted to transition‐metal photocatalysts. This Minireview reports recent developments in the use of acridinium ions and cyanoarene derivatives in organic synthesis. The activation of inert chemical bonds as well as the late‐stage functionalization of biorelevant molecules are discussed, with a special focus on their mechanistic aspects.

Unraveling the complexity of the lipidome requires the development of novel approaches for the structural characterization of lipid species with isomer-level discrimination. Herein, we introduce an online photochemical approach for lipid isomer identification through selective derivatization of double bonds by reaction with singlet oxygen. Lipid hydroperoxide products are generated promptly after laser irradiation. Fragmentation of these species in a mass spectrometer produces diagnostic fragments revealing the C=C locations in the unreacted lipids. This approach uses an inexpensive light source and photosensitizer making it easy to incorporate into any lipidomics workflow. We demonstrate the utility of this approach for the shotgun profiling of C=C locations in different lipid classes present in tissue extracts using electrospray ionization (ESI) and ambient imaging of lipid species differing only by the location of C=C bonds using nanospray desorption electrospray ionization (nano-DESI).

Abstract Recently, dendritic mesoporous silica nanoparticles with widespread applications have attracted great interest. Despite many publications (>800), the terminology “dendritic” is ambiguous. Understanding what possible “dendritic structures” are, their formation mechanisms and the underlying structure–property relationship is fundamentally important. With the advance of characterization techniques such as electron tomography, two types of tree‐branch‐like and flower‐like structures can be distinguished, both described as “dendritic” in the literature. In this Review, we start with the definition of “dendritic”, then provide critical analysis of reported dendritic silica nanoparticles according to their structural classification. We update the understandings of the formation mechanisms of two types of “dendritic” nanoparticles, highlighting how to control their structural parameters. Applications of dendritic mesoporous nanoparticles are also reviewed with a focus on the biomedical field, providing new insights into the structure–property relationship in this family of…

Abstract Emerging asymmetric ionic membranes consisting of two different porous membranes show great superiority in harvesting clean and renewable osmotic energy. The main barriers constraining their applications are incompatible interfaces and a low interfacial ionic transport efficiency, which are detrimental to the long‐term stability and improvement of the power density. Here, continuous‐gradient all‐polysaccharide polyelectrolyte hydrogel membranes prepared by ultrafast reaction/diffusion have been demonstrated to enable high‐performance osmotic energy conversion. Besides an inherent high ion conductivity and excellent ion selectivity, the anti‐swelling polyelectrolyte gradient membranes preserve the ionic diode effect of the asymmetric membranes to facilitate one‐way ion diffusion but circumvent adverse interfacial effects. In consequence, they can present ultrahigh power densities of 7.87 W m −2 by mixing seawater and river water, far superior to state‐of‐the‐art membranes.

Abstract Interfacial electron transfer between cocatalyst and photosensitizer is key in heterogeneous photocatalysis, yet the underlying mechanism remains subtle and unclear. Surfactant coated on the metal cocatalysts, greatly modulating the microenvironment of catalytic sites, is largely ignored. Herein, a series of Pt co‐catalysts with modulated microenvironments, including polyvinylpyrrolidone (PVP) capped Pt nanoparticles (denoted as Pt PVP ), Pt with partially removed PVP (Pt rPVP ), and clean Pt without PVP (Pt), were encapsulated into a metal–organic framework (MOF), UiO‐66‐NH 2 , to afford Pt PVP @UiO‐66‐NH 2 , Pt rPVP @UiO‐66‐NH 2 , and Pt@UiO‐66‐NH 2 , respectively, for photocatalytic hydrogen production. The PVP appears to have a negative influence on the interfacial electron transfer between Pt and the MOF. Compared with Pt PVP @UiO‐66‐NH 2 , the removal of interfacial PVP improves the sluggish kinetics of electron transfer, boosting photocatalytic hydrogen production.

Abstract For a long time, phosphors with long‐lived emission are dominated by rare earth/transition metal ion‐doped sulfides and oxides. Recently, organic materials capable of emitting long‐lived room‐temperature phosphorescence (RTP) are reported, carbon skeletons are almost the exclusive structural feature of the conjugated luminophores. Herein, we reported that boric acid, a non‐metal and C‐free material, could emit RTP with lifetime up to 0.3 s. Detailed investigations indicated the weak conjugation between the n electrons of the O atoms in the B‐O confined space was the possible origin of RTP. Similar RTP was also found in electron‐rich N/F systems, namely, BN and BF 3 (BF 4 − ). Importantly, the vacant orbital of B was found to contribute to the relevant unoccupied molecular orbitals involved in excitation, which is different from previous reports on phosphorescence from arylboronic acids. The results confirm the unique role of B as a versatile structure motif for construction of new RTP materials.

Abstract Molecular nanocarbons containing heptagonal rings have attracted increasing interest due to their dynamic behavior, electronic properties, aromaticity, and solid‐state packing. Heptagon incorporation can not only induce negative curvature within nanocarbon scaffolds, but also confer significantly altered properties through interaction with adjacent non‐hexagonal rings. Despite the disclosure of several beautiful examples in recent years, synthetic strategies toward heptagon‐embedded molecular nanocarbons remain relatively limited due to the intrinsic challenges of heptagon formation and incorporation into polyarene frameworks. In this Review, recent advances in solution‐mediated and surface‐assisted synthesis of heptagon‐containing molecular nanocarbons, as well as the intriguing properties of these frameworks, will be discussed.

Abstract Single‐atom catalysts (SACs) have attracted tremendous interests due to their ultrahigh activity and selectivity. However, the rational control over coordination microenvironment of SACs remains a grand challenge. Herein, a post‐synthetic metal substitution (PSMS) strategy has been developed to fabricate single‐atom Ni catalysts with different N coordination numbers (denoted Ni‐N x ‐C) on pre‐designed N‐doped carbon derived from metal‐organic frameworks. When served for CO 2 electroreduction, the obtained Ni‐N 3 ‐C catalyst achieves CO Faradaic efficiency (FE) up to 95.6 %, much superior to that of Ni‐N 4 ‐C. Theoretical calculations reveal that the lower Ni coordination number in Ni‐N 3 ‐C can significantly enhance COOH* formation, thereby accelerating CO 2 reduction. In addition, Ni‐N 3 ‐C shows excellent performance in Zn–CO 2 battery with ultrahigh CO FE and excellent stability. This work opens up a new and general avenue to coordination microenvironment modulation (MEM) of SACs for CO 2 utilization.

Abstract Exploring earth‐abundant electrocatalysts with excellent activity, robust stability, and multiple functions is crucial for electrolytic hydrogen generation. Porous phosphorized CoNi 2 S 4 yolk‐shell spheres (P‐CoNi 2 S 4 YSSs) were rationally designed and synthesized by a combined hydrothermal sulfidation and gas‐phase phosphorization strategy. Benefiting from the strengthened Ni 3+ /Ni 2+ couple, enhanced electronic conductivity, and hollow structure, the P‐CoNi 2 S 4 YSSs exhibit excellent activity and durability towards hydrogen/oxygen evolution and urea oxidation reactions in alkaline solution, affording low potentials of −0.135 V, 1.512 V, and 1.306 V (versus reversible hydrogen electrode) at 10 mA cm −2 , respectively. Remarkably, when used as the anode and cathode simultaneously, the P‐CoNi 2 S 4 catalyst merely requires a cell voltage of 1.544 V in water splitting and 1.402 V in urea electrolysis to attain 10 mA cm −2 with excellent durability for 100 h, outperforming most of the reported nickel‐based sulfides and even noble‐metal‐based electrocatalysts. This work…

Abstract The Co‐based electrocatalyst is among the most promising candidates for electrochemical oxidation of 5‐hydroxymethylfurfural (HMF). However, the intrinsic active sites and detailed mechanism of this catalyst remains unclear. We combine experimental evidence and a theoretical study to show that electrogenerated Co3+ and Co4+ species act as chemical oxidants but with distinct roles in selective HMF oxidation. It is found that Co3+ is only capable of oxidizing formyl group to produce carboxylate while Co4+ is required for the initial oxidation of hydroxyl group with significantly faster kinetics. As a result, the product distribution shows explicit dependence on the Co oxidation states and selective production of 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA) and 2,5‐furandicarboxylic acid (FDCA) are achieved by tuning the applied potential. This work offers essential mechanistic insight on Co‐catalyzed organic oxidation reactions and might guide the design of more efficient electrocatalysts.

Polymerization at the liquid-liquid interface has attracted much attention for synthesizing ultrathin polymer films for molecular sieving. However, it remains a major challenge to conduct this process outside the alkane-water interface since it not only suffers water-caused side reactions but also is limited to water-soluble monomers. Here, we report the interfacial polymerization at the alkane/ionic liquid interface (IP@AILI) where the ionic liquid acts as the universal solvent for diversified amines to synthesize task-specific polyamide nanofilms. We propose that IP@AILI occurs when acyl chloride diffuses from the alkane into the ionic liquid instead of being triggered by the diffusion of amines as in the conventional alkane-water system, which is demonstrated by thermodynamic partitioning and kinetic monitoring. The prepared polyamide nanofilms with precisely adjustable pore sizes display unprecedented permeability and selectivity in various separation processes.

Abstract Zigzag carbon nanobelts are a long‐sought‐after target for organic synthesis. Herein we report new strategies for designing and synthesizing unprecedented zigzag carbon nanobelts, which present a wave‐like arrangement of hexagons in the unrolled lattice of ( n ,0) single wall carbon nanotubes ( n =16 or 24). The precursors of these zigzag carbon nanobelts are hybrid cyclic arylene oligomers consisting of meta ‐phenylene and 2,6‐naphthalenylene as well as para ‐phenylene units. The Scholl reactions of these cyclic arylene oligomers form multiple carbon‐carbon bonds selectively at the α‐positions of naphthalene units resulting in the corresponding zigzag carbon nanobelts. As monitored with fluorescence spectroscopy, one of these nanobelts binds C 60 with an association constant as high as (6.6±1.1)×10 6 M −1 in the solution in toluene. Computational studies combining linear regression analysis and hypothetical homodesmotic reactions reveal that these zigzag nanobelts have strain in the range of 67.5 to 69.6 kcal mol −1 , and the ladderization step through Scholl reactions is…

Abstract An adaptive coordination structure is vital for selective uranium extraction from seawater. By strategy of molecular imprinting, uranyl is introduced into a multivariate metal–organic framework (MOF) during the synthesis process to guide the in situ construction of proper nanocage structure for targeting uranyl binding. Except for the coordination between uranium with four oxygen from the materials, the axial oxygen of uranyl also forms hydrogen bonds with hydrogen from the phenolic hydroxyl group, which enhances the binding affinity of the material to uranyl. Attributing to the high binding affinity, the adsorbent shows high uranium binding selectivity to uranyl against not only the interfering metal ions, but also the carbonate group that coordinates with uranyl to form [UO2(CO)3]4− in seawater. In natural seawater, the adsorbent realizes a high uranium adsorption capacity of 7.35 mg g−1, together with an 18.38 times higher selectivity to vanadium.

Abstract Core/shell nanocatalysts are a class of promising materials, which achieve the enhanced catalytic activities through the synergy between ligand effect and strain effect. However, it has been challenging to disentangle the contributions from the two effects, which hinders the rational design of superior core/shell nanocatalysts. Herein, we report precise synthesis of PdCu/Ir core/shell nanocrystals, which can significantly boost oxygen evolution reaction (OER) via the exclusive strain effect. The heteroepitaxial coating of four Ir atomic layers onto PdCu nanoparticle gives a relatively thick Ir shell eliminating the ligand effect, but creates a compressive strain of ca. 3.60%. The strained PdCu/Ir catalysts can deliver a low OER overpotential and a high mass activity. Density functional theory (DFT) calculations reveal that the compressive strain in Ir shell downshifts the d‐band center and weakens the binding of the intermediates, causing the enhanced OER activity. The compressive strain also boosts hydrogen evolution reaction (HER) activity and the strained nanocrystals…

Abstract Under topological guidance, the self‐assembly process based on a tetratopic porphyrin synthon results in a hydrogen‐bonded organic framework (HOF) with the predicted square layers topology (sql) but unsatisfied stability. Strikingly, simply introducing a transition metal in the porphyrin center does not change the network topology but drastically causes noticeable change on noncovalent interaction, orbital overlap, and molecular geometry, therefore ultimately giving rise to a series of metalloporphyrinic HOFs with high surface area, and excellent stability (intact after being soaked in boiling water, concentrated HCl, and heated to 270 °C). On integrating both photosensitizers and catalytic sites into robust backbones, this series of HOFs can effectively catalyze the photoreduction of CO2 to CO, and their catalytic performances greatly depend on the chelated metal species in the porphyrin centers. This work enriches the library of stable functional HOFs and expands their applications in photocatalytic CO2 reduction.