The 100 most-cited articles in Angewandte Chemie International Edition, 2021

The amalgamation of different disciplines is at the heart of reticular chemistry and has broadened the boundaries of chemistry by opening up an infinite space of chemical composition, structure, and material properties. Reticular design has enabled the precise prediction of crystalline framework structures, tunability of chemical composition, incorporation of various functionalities onto the framework backbone, and as a consequence, fine-tuning of metal-organic framework (MOF) and covalent organic framework (COF) properties beyond that of any other material class. Leveraging the unique properties of reticular materials has resulted in significant advances from both a fundamental and an applied perspective. Here, we wish to review the milestones in MOF and COF research and give a critical view on progress in their real-world applications. Finally, we briefly discuss the major challenges in the field that need to be addressed to pave the way for industrial applications.

Abstract Singlet oxygen ( 1 O 2 ) is an excellent active species for the selective degradation of organic pollutions. However, it is difficult to achieve high efficiency and selectivity for the generation of 1 O 2 . In this work, we develop a graphitic carbon nitride supported Fe single‐atoms catalyst (Fe 1 /CN) containing highly uniform Fe‐N 4 active sites with a high Fe loading of 11.2 wt %. The Fe 1 /CN achieves generation of 100 % 1 O 2 by activating peroxymonosulfate (PMS), which shows an ultrahigh p‐chlorophenol degradation efficiency. Density functional theory calculations results demonstrate that in contrast to Co and Ni single‐atom sites, the Fe‐N 4 sites in Fe 1 /CN adsorb the terminal O of PMS, which can facilitate the oxidization of PMS to form SO 5 .− , and thereafter efficiently generate 1 O 2 with 100 % selectivity. In addition, the Fe 1 /CN exhibits strong resistance to inorganic ions, natural organic matter, and pH value during the degradation of organic pollutants in the presence of PMS. This work develops a novel catalyst for the 100 % selective production of 1 O…

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 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.

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 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 ZnSO 4 electrolyte, the free water and coordinated water in Zn 2+ solvation sheath gradually interact with the antisolvent, which minimizes water activity and weakens Zn 2+ 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…

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 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 M3+ vacancies) accelerate the evolution…

Abstract Compared to modern fossil‐fuel‐based refineries, the emerging electrocatalytic refinery (e‐refinery) is a more sustainable and environmentally benign strategy to convert renewable feedstocks and energy sources into transportable fuels and value‐added chemicals. A crucial step in conducting e‐refinery processes is the development of appropriate reactions and optimal electrocatalysts for efficient cleavage and formation of chemical bonds. However, compared to well‐studied primary reactions (e.g., O 2 reduction, water splitting), the mechanistic aspects and materials design for emerging complex reactions are yet to be settled. To address this challenge, herein, we first present fundamentals of heterogeneous electrocatalysis and some primary reactions, and then implement these to establish the framework of e‐refinery by coupling in situ generated intermediates (integrated reactions) or products (tandem reactions). We also present a set of materials design principles and strategies to efficiently manipulate the reaction intermediates and pathways.

Photothermal therapy (PTT) is an extremely promising tumor therapeutic modality. However, excessive heat inevitably injures normal tissues near tumors, and the damage to cancer cells caused by mild hyperthermia is easily repaired by stress-induced heat shock proteins (HSPs). Thus, maximizing the PTT efficiency and minimizing the damage to healthy tissues simultaneously by adopting appropriate therapeutic temperatures is imperative. Herein, an innovative strategy is reported: ferroptosis-boosted mild PTT based on a single-atom nanozyme (SAzyme). The Pd SAzyme with atom-economical utilization of catalytic centers exhibits peroxidase (POD) and glutathione oxidase (GSHOx) mimicking activities, and photothermal conversion performance, which can result in ferroptosis featuring the up-regulation of lipid peroxides (LPO) and reactive oxygen species (ROS). The accumulation of LPO and ROS provides a powerful approach for cleaving HSPs, which enables Pd SAzyme-mediated mild-temperature PTT.

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 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‐Nx‐C) on pre‐designed N‐doped carbon derived from metal‐organic frameworks. When served for CO2 electroreduction, the obtained Ni‐N3‐C catalyst achieves CO Faradaic efficiency (FE) up to 95.6 %, much superior to that of Ni‐N4‐C. Theoretical calculations reveal that the lower Ni coordination number in Ni‐N3‐C can significantly enhance COOH* formation, thereby accelerating CO2 reduction. In addition, Ni‐N3‐C shows excellent performance in Zn–CO2 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 CO2 utilization.

Abstract Prussian blue analogs (PBAs) are considered as reliable and promising cathode materials for aqueous Zn‐ion batteries (AZIBs), but they suffer from low capacity and poor cycling stability due to insufficient active sites and structural damage caused by the ion insertion/extraction processes. Herein, a template‐engaged ion exchange approach has been developed for the synthesis of Co‐substituted Mn‐rich PBA hollow spheres (CoMn‐PBA HSs) as cathode materials for AZIBs. Benefiting from the multiple advantageous features including hollow structure, abundant active sites, fast Zn 2+ ion diffusion, and partial Co substitution, the CoMn‐PBA HSs electrode shows efficient zinc ion storage properties in terms of high capacity, decent rate capability and prolonged cycle life.

Abstract Defects have been found to enhance the electrocatalytic performance of NiFe‐LDH for oxygen evolution reaction (OER). Nevertheless, their specific configuration and the role played in regulating the surface reconstruction of electrocatalysts remain ambiguous. Herein, cationic vacancy defects are generated via aprotic‐solvent‐solvation‐induced leaking of metal cations from NiFe‐LDH nanosheets. DFT calculation and in situ Raman spectroscopic observation both reveal that the as‐generated cationic vacancy defects tend to exist as VM (M=Ni/Fe); under increasing applied voltage, they tend to assume the configuration VMOH, and eventually transform into VMOH‐H which is the most active yet most difficult to form thermodynamically. Meanwhile, with increasing voltage the surface crystalline Ni(OH)x in the NiFe‐LDH is gradually converted into disordered status; under sufficiently high voltage when oxygen bubbles start to evolve, local NiOOH species become appearing, which is the residual product from the formation of vacancy VMOH‐H. Thus, we demonstrate that the cationic defects evolve…

Transition metal hydroxides (M-OH) and their heterostructures (X|M-OH, where X can be a metal, metal oxide, metal chalcogenide, metal phosphide, etc.) have recently emerged as highly active electrocatalysts for hydrogen evolution reaction (HER) of alkaline water electrolysis. Lattice hydroxide anions in metal hydroxides are primarily responsible for observing such an enhanced HER activity in alkali that facilitate water dissociation and assist the first step, the hydrogen adsorption. Unfortunately, their poor electronic conductivity had been an issue of concern that significantly lowered its activity. Interesting advancements were made when heterostructured hydroxide materials with a metallic and or a semiconducting phase were found to overcome this pitfall. However, in the midst of recently evolving metal chalcogenide and phosphide based HER catalysts, significant developments made in the field of metal hydroxides and their heterostructures catalysed alkaline HER and their superiority have unfortunately been given negligible attention. This review, unlike others, begins with the…

Abstract Dual‐metal single‐atom catalysts exhibit superior performance for oxygen reduction reaction (ORR), however, the synergistic catalytic mechanism is not deeply understood. Herein, we report a dual‐metal single‐atom catalyst consisted of Cu−N 4 and Zn−N 4 on the N‐doped carbon support (Cu/Zn−NC). It exhibits high‐efficiency ORR activity with an E onset of 0.98 V and an E 1/2 of 0.83 V, excellent stability (no degradation after 10 000 cycles), surpassing state‐of‐the‐art Pt/C and great mass of Pt‐free single atom catalysts. Operando XANES demonstrates that the Cu−N 4 as active center experiences the change from atomic dispersion to cluster with the cooperation of Zn−N 4 during ORR process, and then turns to single atom state again after reaction. DFT calculation further indicates that the adjustment effect of Zn on the d‐orbital electron distribution of Cu could benefit to the stretch and cleavage of O‐O on Cu active center, speeding up the process of rate determining step of OOH*.

Abstract We synthesized a series of carbon‐supported atomic metal‐N‐C catalysts (M‐SACs: M=Mn, Fe, Co, Ni, Cu) with similar structural and physicochemical properties to uncover their catalytic activity trends and mechanisms. The peroxymonosulfate (PMS) catalytic activity trends are Fe‐SAC>Co‐SAC>Mn‐SAC>Ni‐SAC>Cu‐SAC, and Fe‐SAC displays the best single‐site kinetic value (1.65×10 5 min −1 mol −1 ) compared to the other metal‐N‐C species. First‐principles calculations indicate that the most reasonable reaction pathway for 1 O 2 production is PMS→OH*→O*→ 1 O 2 ; M‐SACs that exhibit moderate and near‐average Gibbs free energies in each reaction step have a better catalytic activity, which is the key for the outstanding performance of Fe‐SACs. This study gives the atomic‐scale understanding of fundamental catalytic trends and mechanisms of PMS‐assisted reactive oxygen species production via M‐SACs, thus providing guidance for developing M‐SACs for catalytic organic pollutant degradation.

Abstract The overall water splitting efficiency is mainly restricted by the slow kinetics of oxygen evolution. Therefore, it is essential to develop active oxygen evolution catalysts. In this context, we designed and synthesized a tungsten oxide catalyst with oxygen vacancies for photocatalytic oxygen evolution, which exhibited a higher oxygen evolution rate of 683 μmol h −1 g −1 than that of pure WO 3 (159 μmol h −1 g −1 ). Subsequent studies through transient absorption spectroscopy found that the oxygen vacancies can produce electron trapping states to inhibit the direct recombination of photogenerated carriers. Additionally, a Pt cocatalyst can promote electron trap states to participate in the reaction to improve the photocatalytic performance further. This work uses femtosecond transient absorption spectroscopy to explain the photocatalytic oxygen evolution mechanism of inorganic materials and provides new insights into the design of high‐efficiency water‐splitting catalysts.

Abstract Ultrathin two‐dimensional catalysts are attracting attention in the field of electrocatalytic hydrogen evolution. This work describe a composite material design in which CoP nanoparticles doped with Ru single‐atom sites supported on carbon dots (CDs) single‐layer nanosheets formed by splicing CDs (Ru1CoP/CDs). Small CD fragments bore abundant functional groups, analogous to pieces of a jigsaw puzzle, and could provide a high density of binding sites to immobilize Ru1CoP. The single‐particle‐thick nanosheets formed by splicing CDs acted as supports, which improved the conductivity of the electrocatalyst and the stability of the catalyst during operation. The Ru1CoP/CDs formed from doping atomic Ru dispersed on CoP showed very high efficiency for the hydrogen evolution reaction (HER) over a wide pH range. The catalyst prepared under optimized conditions displayed outstanding stability and activity: the overpotential for the HER at a current density of 10 mA cm−2 was as low as 51 and 49 mV under alkaline and acidic conditions, respectively. Density functional theory…

Abstract Although Fenton or Fenton‐like reactions have been widely used in the environment, biology, life science, and other fields, the sharp decrease in their activity under macroneutral conditions is still a large problem. This study reports a MoS2 cocatalytic heterogeneous Fenton (CoFe2O4/MoS2) system capable of sustainably degrading organic pollutants, such as phenol, in a macroneutral buffer solution. An acidic microenvironment in the slipping plane of CoFe2O4 is successfully constructed by chemically bonding with MoS2. This microenvironment is not affected by the surrounding pH, which ensures the stable circulation of Fe3+/Fe2+ on the surface of CoFe2O4/MoS2 under neutral or even alkaline conditions. Additionally, CoFe2O4/MoS2 always exposes “fresh” active sites for the decomposition of H2O2 and the generation of 1O2, effectively inhibiting the production of iron sludge and enhancing the remediation of organic pollutants, even in actual wastewater. This work not only experimentally verifies the existence of an acidic microenvironment on the surface of heterogeneous catalysts…

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…

For decades, turnover frequency (TOF) has served as an accurate descriptor of the intrinsic activity of a catalyst, including those in electrocatalytic reactions involving both fuel generation and fuel consumption. Unfortunately, in most of the recent reports in this area, TOF is often not properly reported or not reported at all, in contrast to the overpotentials at a benchmarking current density. The current density is significant in determining the apparent activity, but it is affected by catalyst-centric parasitic reactions, electrolyte-centric competing reactions, and capacitance. Luckily, a properly calculated TOF can precisely give the intrinsic activity free from these phenomena in electrocatalysis. In this Viewpoint we ask: 1) What makes the commonly used activity markers unsuitable for intrinsic activity determination? 2) How can TOF reflect the intrinsic activity? 3) Why is TOF still underused in electrocatalysis? 4) What methods are used in TOF determination? and 5) What is essential in the more accurate calculation of TOF? Finally, the significance of normalizing TOF by…

Aptamers are short oligonucleotides isolated in vitro from randomized libraries that can bind to specific molecules with high affinity, and offer a number of advantages relative to antibodies as biorecognition elements in biosensors. However, it remains difficult and labor-intensive to develop aptamer-based sensors for small-molecule detection. Here, we review the challenges and advances in the isolation and characterization of small-molecule-binding DNA aptamers and their use in sensors. First, we discuss in vitro methodologies for the isolation of aptamers, and provide guidance on selecting the appropriate strategy for generating aptamers with optimal binding properties for a given application. We next examine techniques for characterizing aptamer-target binding and structure. Afterwards, we discuss various small-molecule sensing platforms based on original or engineered aptamers, and their detection applications. Finally, we conclude with a general workflow to develop aptamer-based small-molecule sensors for real-world applications.

Abstract Polymeric carbon nitride (PCN) as a class of two‐electron oxygen reduction reaction (2 e − ORR) photocatalyst has attracted much attention for H 2 O 2 production. However, the low activity and inferior selectivity of 2 e − ORR greatly restrict the H 2 O 2 production efficiency. Herein, we develop a new strategy to synthesize hydrophilic, fragmented PCN photocatalyst by the terminating polymerization (TP‐PCN) effect of iodide ions. The obtained TP‐PCN with abundant edge active sites (AEASs), which can form quasi‐homogeneous photocatalytic system, exhibits superior H 2 O 2 generation rate (3265.4 μM h −1 ), far surpassing PCN and other PCN‐based photocatalysts. DFT calculations further indicate that TP‐PCN is more favorable for electron transiting from β spin‐orbital to the π* orbitals of O 2 , which optimizes O 2 activation and reduces the energy barrier of H 2 O 2 formation. This work provides a new concept for designing functional photocatalysts and understanding the mechanism of O 2 activation in ORR for H 2 O 2 production.

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 Aqueous Zn batteries are challenged by water decomposition and dendrite growth due to the absence of a dense Zn‐ion conductive solid electrolyte interphase (SEI) to inhibit the hydrogen evolution reaction (HER). Here, we design a low‐concentration aqueous Zn(OTF)2‐Zn(NO3)2 electrolyte to in situ form a robust inorganic ZnF2‐Zn5(CO3)2(OH)6‐organic bilayer SEI, where the inorganic inner layer promotes Zn‐ion diffusion while the organic outer layer suppresses water penetration. We found that the insulating Zn5(OH)8(NO3)2⋅2 H2O layer is first formed on the Zn anode surface by the self‐terminated chemical reaction of NO3− with Zn2+ and OH− generated via HER, and then it transforms into Zn‐ion conducting Zn5(CO3)2(OH)6, which in turn promotes the formation of ZnF2 as the inner layer. The organic‐dominated outer layer is formed by the reduction of OTF−. The in situ formed SEI enables a high Coulombic efficiency (CE) of 99.8 % for 200 h in Ti∥Zn cells, and a high energy density (168 Wh kg−1) with 96.5 % retention for 700 cycles in Zn∥MnO2 cells with a low Zn/MnO2 capacity ratio of…

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 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.

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 storage…

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 MXene (e.g., Ti 3 C 2 ) represents an important class of two‐dimensional (2D) materials owing to its unique metallic conductivity and tunable surface chemistry. However, the mainstream synthetic methods rely on the chemical etching of MAX powders (e.g., Ti 3 AlC 2 ) using hazardous HF or alike, leading to MXene sheets with fluorine termination and poor ambient stability in colloidal dispersions. Here, we demonstrate a fluoride‐free, iodine (I 2 ) assisted etching route for preparing 2D MXene (Ti 3 C 2 T x , T=O, OH) with oxygen‐rich terminal groups and intact lattice structure. More than 71 % of sheets are thinner than 5 nm with an average size of 1.8 μm. They present excellent thin‐film conductivity of 1250 S cm −1 and great ambient stability in water for at least 2 weeks. 2D MXene sheets with abundant oxygen surface groups are excellent electrode materials for supercapacitors, delivering a high gravimetric capacitance of 293 F g −1 at a scan rate of 1 mV s −1 , superior to those made from fluoride‐based etchants (<290 F g −1 at 1 mV s −1 ). Our strategy provides a…

The formation of a vast number of different multielement active sites in compositionally complex solid solution materials, often more generally termed high-entropy alloys, offers new and unique concepts in catalyst design, which mitigate existing limitations and change the view on structure-activity relations. We discuss these concepts by summarising the currently existing fundamental knowledge and critically assess the chances and limitations of this material class, also highlighting design strategies. A roadmap is proposed, illustrating which of the characteristic concepts could be exploited using which strategy, and which breakthroughs might be possible to guide future research in this highly promising material class for (electro)catalysis.

Abstract MXenes have attracted great interests as supercapacitors due to their metallic conductivity, high density, and hydrophilic nature. Herein we report Ti 3 C 2 ‐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 Ti 3 C 2 ‐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 H 2 SO 4 . Symmetric supercapacitor Ti 3 C 2 ‐Cu//Ti 3 C 2 ‐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 Nickel hydroxide (Ni(OH) 2 ) is a promising electrocatalyst for the 5‐hydroxymethylfurfural oxidation reaction (HMFOR) and the dehydronated intermediates Ni(OH)O species are proved to be active sites for HMFOR. In this study, Ni(OH) 2 is modified by platinum to adjust the electronic structure and the current density of HMFOR improves 8.2 times at the Pt/Ni(OH) 2 electrode compared with that on Ni(OH) 2 electrode. Operando methods reveal that the introduction of Pt optimized the redox property of Ni(OH) 2 and accelerate the formation of Ni(OH)O during the catalytic process. Theoretical studies demonstrate that the enhanced Ni(OH)O formation kinetics originates from the reduced dehydrogenation energy of Ni(OH) 2 . The product analysis and transition state simulation prove that the Pt also reduces adsorption energy of HMF with optimized adsorption behavior as Pt can act as the adsorption site of HMF. Overall, this work here provides a strategy to design an efficient and universal nickel‐based catalyst for HMF electro‐oxidation, which can also be extended to other Ni‐based…

Abstract Covalent organic frameworks (COFs) have emerged as an important class of organic semiconductors and photocatalysts for the hydrogen evolution reaction (HER)from water. To optimize their photocatalytic activity, typically the organic moieties constituting the frameworks are considered and the most suitable combinations of them are searched for. However, the effect of the covalent linkage between these moieties on the photocatalytic performance has rarely been studied. Herein, we demonstrate that donor‐acceptor (D‐A) type imine‐linked COFs can produce hydrogen with a rate as high as 20.7 mmol g −1 h −1 under visible light irradiation, upon protonation of their imine linkages. A significant red‐shift in light absorbance, largely improved charge separation efficiency, and an increase in hydrophilicity triggered by protonation of the Schiff‐base moieties in the imine‐linked COFs, are responsible for the improved photocatalytic performance.

Abstract Cancer has emerged over the last decades as one of the deadliest diseases in the world. Among the most commonly used techniques (i.e. surgery, immunotherapy, radiotherapy or chemotherapy), increasing attention has been devoted towards photodynamic therapy. However, the vast majority of clinically applied photosensitizers are not ideal and associated with several limitations including poor aqueous solubility, poor photostability and slow clearance from the body, causing photosensitivity. In an effort to overcome these drawbacks, much attention has been devoted towards the incorporation of a metal ion. Herein, the clinical development of metal‐containing compounds including Purlytin ® , Lutrin ® /Antrin ® , Photosens ® , TOOKAD ® soluble or TLD‐1433 is critically reviewed.

Abstract Developing Type‐I photosensitizers is considered as an efficient approach to overcome the deficiency of traditional photodynamic therapy (PDT) for hypoxic tumors. However, it remains a challenge to design photosensitizers for generating reactive oxygen species by the Type‐I process. Herein, we report a series of α,β‐linked BODIPY dimers and a trimer that exclusively generate superoxide radical (O 2 −. ) by the Type‐I process upon light irradiation. The triplet formation originates from an effective excited‐state relaxation from the initially populated singlet (S 1 ) to triplet (T 1 ) states via an intermediate triplet (T 2 ) state. The low reduction potential and ultralong lifetime of the T 1 state facilitate the efficient generation of O 2 −. by inter‐molecular charge transfer to molecular oxygen. The energy gap of T 1 ‐S 0 is smaller than that between 3 O 2 and 1 O 2 thereby precluding the generation of singlet oxygen by the Type‐II process. The trimer exhibits superior PDT performance under the hypoxic environment.

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 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 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) 3 O 4 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 modulation effect has been widely investigated to tune the electronic state of single‐atomic M‐N‐C catalysts to enhance the activity of oxygen reduction reaction (ORR). However, the in‐depth study of modulation effect is rarely reported for the isolated dual‐atomic metal sites. Now, the catalytic activities of Fe‐N 4 moiety can be enhanced by the adjacent Pt‐N 4 moiety through the modulation effect, in which the Pt‐N 4 acts as the modulator to tune the 3d electronic orbitals of Fe‐N 4 active site and optimize ORR activity. Inspired by this principle, we design and synthesize the electrocatalyst that comprises isolated Fe‐N 4 /Pt‐N 4 moieties dispersed in the nitrogen‐doped carbon matrix (Fe‐N 4 /Pt‐N 4 @NC) and exhibits a half‐wave potential of 0.93 V vs. RHE and negligible activity degradation (ΔE 1/2 =8 mV) after 10000 cycles in 0.1 M KOH. We also demonstrate that the modulation effect is not effective for optimizing the ORR performances of Co‐N 4 /Pt‐N 4 and Mn‐N 4 /Pt‐N 4 systems.

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 TiO 2 /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 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 The mainstream applications of visible‐light photoredox catalysis predominately involve outer‐sphere single‐electron transfer (SET) or energy transfer (EnT) processes of precious metal RuII or IrIII complexes or of organic dyes with low photostability. Earth‐abundant metal‐based MnLn‐type (M=metal, Ln=polydentate ligands) complexes are rapidly evolving as alternative photocatalysts as they offer not only economic and ecological advantages but also access to the complementary inner‐sphere mechanistic modes, thereby transcending their inherent limitations of ultrashort excited‐state lifetimes for use as effective photocatalysts. The generic process, termed visible‐light‐induced homolysis (VLIH), entails the formation of suitable light‐absorbing ligated metal–substrate complexes (MnLn‐Z; Z=substrate) that can undergo homolytic cleavage to generate Mn−1Ln and Z. for further transformations.

Abstract Cu‐based electrocatalysts facilitate CO 2 electrochemical reduction (CO 2 ER) to produce multi‐carbon products. However, the roles of Cu 0 and Cu + and the mechanistic understanding remain elusive. This paper describes the controllable construction of Cu 0 ‐Cu + sites derived from the well‐dispersed cupric oxide particles supported on copper phyllosilicate lamella to enhance CO 2 ER performance. 20 % Cu/CuSiO 3 shows the superior CO 2 ER performance with 51.8 % C 2 H 4 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 CO 2 ER activity is mainly attributed to the synergism of Cu 0 ‐Cu + pairs: Cu 0 activates CO 2 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 CO 2 ER.

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 Heteroatom doped atomically dispersed Fe 1 ‐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 Fe 1 ‐NC catalyst was obtained as a model, which displays a superior activity for ORR towards the traditional Fe‐NC materials. 57 Fe Mössbauer spectroscopy and electron paramagnetic resonance spectroscopy revealed that incorporation of S in the second coordination sphere of Fe 1 ‐NC can induce the transition of spin polarization configuration. Operando 57 Fe Mössbauer spectra definitively identified the low spin single‐Fe 3+ ‐atom of C‐FeN 4 ‐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…

At its core, reticular chemistry has translated the precision and expertise of organic and inorganic synthesis to the solid state. While initial excitement over metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) was undoubtedly fueled by their unprecedented porosity and surface areas, the most profound scientific innovation of the field has been the elaboration of design strategies for the synthesis of extended crystalline solids through strong directional bonds. In this contribution we highlight the different classes of reticular materials that have been developed, how these frameworks can be functionalized, and how complexity can be introduced into their backbones. Finally, we show how the structural control over these materials is being extended from the molecular scale to their crystal morphology and shape on the nanoscale, all the way to their shaping on the bulk scale.

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…

A facile synthesis is reported of two-dimensional (2D) bimetallic (Fe/Co=1:2) metal-organic frameworks (MOF, ca. 2.2 nm thick) via simple stirring of the reaction mixture of Fe/Co salts and 1,4-benzene dicarboxylic acid (1,4-BDC) in the presence of triethylamine and water at room temperature. The mechanism of the 2D, rather than bulk, MOF was revealed by studying the role of each component in the reaction mixture. It was found that these 2D MOF-Fe/Co(1:2) exhibited excellent electrocatalytic activity for the oxygen evolution reaction (OER) under basic conditions. The electrocatalytic mechanism was disclosed via both experimental results and density functional theory (DFT) calculation. The 2D morphology and co-doping of Fe/Co contributed to the superior OER performance of the 2D MOF-Fe/Co(1:2). The simple and efficient synthetic method is suitable for the mass production and future commercialization of functional 2D MOF with low cost and high yield.

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 Adsorption‐based iodine (I2) capture has great potential for the treatment of radioactive nuclear waste. In this study, we apply a “multivariate” synthetic strategy to construct ionic covalent organic frameworks (iCOFs) with a large surface area, high pore volume, and abundant binding sites for I2 capture. The optimized material iCOF‐AB‐50 exhibits a static I2 uptake capacity of 10.21 g g−1 at 75 °C and a dynamic uptake capacity of 2.79 g g−1 at ≈400 ppm I2 and 25 °C, far exceeding the performances of previously reported adsorbents under similar conditions. iCOF‐AB‐50 also exhibits fast adsorption kinetics, good moisture tolerance, and full reusability. The promoting effect of ionic groups on I2 adsorption has been elucidated by experimentally identifying the iodine species adsorbed at different sites and calculating their binding energies. This work demonstrates the essential role of balancing the textural properties and binding sites of the adsorbent in achieving a high I2 capture performance.

Abstract The all‐inorganic nature of CsPbI 3 perovskites allows to enhance stability in perovskite devices. Research efforts have led to improved stability of the black phase in CsPbI 3 films; however, these strategies—including strain and doping—are based on organic‐ligand‐capped perovskites, which prevent perovskites from forming the close‐packed quantum dot (QD) solids necessary to achieve high charge and thermal transport. We developed an inorganic ligand exchange that leads to CsPbI 3 QD films with superior phase stability and increased thermal transport. The atomic‐ligand‐exchanged QD films, once mechanically coupled, exhibit improved phase stability, and we link this to distributing strain across the film. Operando measurements of the temperature of the LEDs indicate that KI‐exchanged QD films exhibit increased thermal transport compared to controls that rely on organic ligands. The LEDs exhibit a maximum EQE of 23 % with an electroluminescence emission centered at 640 nm (FWHM: ≈31 nm). These red LEDs provide an operating half‐lifetime of 10 h (luminance of 200 cd m −2 ) and…

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 CO 2 reduction reaction (CO 2 RR) processes. Lastly, key challenges and…

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 (NiCo2−xFexO4 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 NiCo2−xFexO4 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 RuO2.

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 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 We designed and synthesized a colorless transparent glassy polyurethane assembled using low‐molecular‐weight oligomers carrying a large number of loosely packed weak hydrogen bonds (H‐bonds), which has a glass transition temperature ( T g ) up to 36.8 °C and behaves unprecedentedly robust stiffness with a tensile Young's modulus of 1.56±0.03 GPa. Fast room‐temperature self‐healing was observed in this polymer network: the broken glassy polyurethane (GPU) specimen can recover to a tensile strength up 7.74±0.76 MPa after healing for as little as 10 min, which is prominent compared to reported room‐temperature self‐healing polymers. The high density of loose‐packed hydrogen bonds can reversibly dissociate/associate below T g of GPU (that is secondary relaxation), which enables the reconfiguration of the damaged network in the fractured interfaces, despite the extremely slow diffusion dynamics of molecular chains under room temperature. This GPU shows potential application as an optical lens.

Abstract In this work we study the role of alkali metal cation concentration and electrolyte pH in altering the kinetics of the hydrogen evolution reaction (HER) at gold (Au) electrodes. We show that at moderately alkaline pH (pH 11), increasing the cation concentration significantly enhances the HER activity on Au electrodes (with a reaction order ≈0.5). Based on these results we suggest that cations play a central role in stabilizing the transition state of the rate‐determining Volmer step by favorably interacting with the dissociating water molecule (*H–OH δ− –cat + ). Moreover, we show that increasing electrolyte pH (pH 10 to pH 13) tunes the local field strength, which in turn indirectly enhances the activity of HER by tuning the near‐surface cation concentration. Interestingly, a too high near‐surface cation concentration (at high pH and high cation concentration) leads to a lowering of the HER activity, which we ascribe to a blockage of the surface by near‐surface cations.

Abstract Photocatalytic reduction of CO2 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 CO2 photoreduction with pure H2O or sacrificial agents usually suffers from low catalytic efficiency, poor stability, or cost‐ineffective atom economy. A recent surge of developments, in which photocatalytic CO2 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 CO2 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 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 RuO 2 sphere for HER and OER, in which the Co single atom in the RuO 2 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.

Endowing a cholesteric liquid crystal elastomer (CLCE) exhibiting a helicoidal nanostructure with dynamically tailorable functionalities is of paramount significance for its emerging applications in diverse fields such as adaptive optics and soft robotics. Here, a mechanochromic, shape-programmable and self-healable CLCE is judiciously designed and synthesized through integrating dynamic covalent boronic ester bonds into the main-chain CLCE polymer network. The circularly polarized reflection of CLCEs can be reversibly and dynamically tuned across the entire visible spectrum by mechanical stretching. Thanks to the introduction of dynamic boronic ester bonds, the CLCEs were found to show robust reprogrammable and self-healing capabilities. The research disclosed herein can provide new insights into the development of 4D (color and 3D shape) programmable photonic actuators towards bioinspired camouflage, adaptive optical systems, and next-generation intelligent machines.

Abstract A built‐in electric field in electrocatalyst can significantly accumulate higher concentration of NO3− ions near electrocatalyst surface region, thus facilitating mass transfer for efficient nitrate removal at ultra‐low concentration and electroreduction reaction (NO3RR). A model electrocatalyst is created by stacking CuCl (111) and rutile TiO2 (110) layers together, in which a built‐in electric field induced from the electron transfer from TiO2 to CuCl (CuCl_BEF) is successfully formed . This built‐in electric field effectively triggers interfacial accumulation of NO3− ions around the electrocatalyst. The electric field also raises the energy of key reaction intermediate *NO to lower the energy barrier of the rate determining step. A NH3 product selectivity of 98.6 %, a low NO2− production of <0.6 %, and mass‐specific ammonia production rate of 64.4 h−1 is achieved, which are all the best among studies reported at 100 mg L−1 of nitrate concentration to date.

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 To avoid the energy‐consuming step of direct N≡N bond cleavage, photocatalytic N 2 fixation undergoing the associative pathways has been developed for mild‐condition operation. However, it is a fundamental yet challenging task to gain comprehensive understanding on how the associative pathways (i.e., alternating vs. distal) are influenced and altered by the fine structure of catalysts, which eventually holds the key to significantly promote the practical implementation. Herein, we introduce Fe dopants into TiO 2 nanofibers to stabilize oxygen vacancies and simultaneously tune their local electronic structure. The combination of in situ characterizations with first‐principles simulations reveals that the modulation of local electronic structure by Fe dopants turns the hydrogenation of N 2 from associative alternating pathway to associative distal pathway. This work provides fresh hints for rationally controlling the reaction pathways toward efficient photocatalytic nitrogen fixation.

Ferroptosis regulates cell death through reactive oxygen species (ROS)-associated lipid peroxide accumulation, which is expected to affect the structure and polarity of lipid droplets (LDs), but with no clear evidence. Herein, we report the first example of an LD/nucleus dual-targeted ratiometric fluorescent probe, CQPP, for monitoring polarity changes in the cellular microenvironment. Due to the donor-acceptor structure of CQPP, it offers ratiometric fluorescence emission and fluorescence lifetime signals that reflect polarity variations. Using nucleus imaging as a reference, CQPP was applied to report the increase in LD polarity and the homogenization of polarity between LDs and cytoplasm in the ferroptosis model. This LD/nucleus dual-targeted fluorescent probe shows the great potential of using fluorescence imaging to study ferroptosis and ferroptosis-related diseases.

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 The electrocatalytic carbon dioxide (CO 2 ) reduction reaction (CO 2 RR) into hydrocarbons is a promising approach for greenhouse gas mitigation, but many details of this dynamic reaction remain elusive. Here, time‐resolved surface‐enhanced Raman spectroscopy (TR‐SERS) is employed to successfully monitor the dynamics of CO 2 RR intermediates and Cu surfaces with sub‐second time resolution. Anodic treatment at 1.55 V vs. RHE and subsequent surface oxide reduction (below −0.4 V vs. RHE) induced roughening of the Cu electrode surface, which resulted in hotspots for TR‐SERS, enhanced time resolution (down to ≈0.7 s) and fourfold improved CO 2 RR efficiency toward ethylene. With TR‐SERS, the initial restructuring of the Cu surface was followed (<7 s), after which a stable surface surrounded by increased local alkalinity was formed. Our measurements revealed that a highly dynamic CO intermediate, with a characteristic vibration below 2060 cm −1 , is related to C−C coupling and ethylene production (−0.9 V vs. RHE), whereas lower cathodic bias (−0.7 V vs. RHE) resulted in gaseous…

Abstract Electrochemical reduction of CO2 (CO2RR) into valuable hydrocarbons is appealing in alleviating the excessive CO2 level. We present the very first utilization of metallic bismuth–tin (Bi‐Sn) aerogel for CO2RR 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 FEHCOOH of 93.9 %. Moreover, the Bi‐Sn aerogel achieves a FEHCOOH 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 Spinel zinc cobalt oxide (ZnCo2O4) 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 t2g6eg0 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 ZnCo2O4 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 ZnCo2O4, while not working for Co3O4. The activity of the best spin‐state‐engineered ZnCo2O4 outperforms other typical Co‐based oxides.

Abstract Development of computation‐ready metal–organic framework databases (MOF DBs) has accelerated high‐throughput computational screening (HTCS) of materials to identify the best candidates for gas storage and separation. These DBs were constructed using structural curations to make MOFs directly usable for molecular simulations, which caused the same MOF to be reported with different structural features in different DBs. We examined thousands of common materials of the two recently updated, very widely used MOF DBs to reveal how structural discrepancies affect simulated CH 4 , H 2 , CO 2 uptakes and CH 4 /H 2 separation performances of MOFs. Results showed that DB selection has a significant effect on the calculated gas uptakes and ideal selectivities of materials at low pressure. A detailed analysis on the curated structures was provided to isolate the critical elements of MOFs determining the gas uptakes. Identification of the top‐performing materials for gas separation was shown to strongly depend on the DB used in simulations.

Abstract The activity of heterogeneous photocatalytic H 2 O 2 activation in Fenton‐like processes is closely related to the local electron density of reaction centre atoms. However, the recombination of electron‐hole pairs arising from random charge transfer greatly restricts the oriented electron delivery to active center. Here we show a defect engineered iron single atom photocatalyst (Fe 1 ‐N v /CN, single Fe atoms dispersed on carbon nitride with abundant nitrogen vacancies) for the activation of H 2 O 2 under visible light irradiation. Based on DFT calculations and transient absorption spectroscopy results, the engineered nitrogen vacancies serve as the electron trap sites, which can directionally drive the electrons to concentrate on Fe atoms. The formation of highly concentrated electrons density at Fe sites significantly improves the H 2 O 2 conversion efficiency. Therefore, the optimized single atom catalyst exhibiting a higher ciprofloxacin degradation activity, which was up to 18 times that of pristine CN.

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 Pd 2 DAC was synthesized and used for electrochemical CO 2 reduction reaction (CO 2 RR) for the first time. The as‐obtained Pd 2 DAC exhibited superior CO 2 RR catalytic performance with 98.2 % CO faradic efficiency at −0.85 V vs. RHE, far exceeding that of Pd 1 SAC, and coupled with long‐term stability. The density functional theory (DFT) calculations revealed that the intrinsic reason for the superior activity of Pd 2 DAC toward CO 2 RR was the electron transfer between Pd atoms at the dimeric Pd sites. Thus, Pd 2 DAC possessed moderate adsorption strength of CO*, which was beneficial for CO production in CO 2 RR.

Abstract Electrochemical CO2 reduction reaction (CO2RR) to multicarbon hydrocarbon and oxygenate (C2+) 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 Cu0/Cu+ interfaces by physically mixing Cu nanoparticles and CuI powders. The composite catalyst achieves a remarkable C2+ 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 CO2RR conditions. The high‐rate C2+ 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 Strong metal–support interactions (SMSI) is an important concept in heterogeneous catalysis. Herein, we demonstrate that the Au‐TiO 2 SMSI of Au/TiO 2 catalysts sensitively depends on both Au nanoparticle (NP) sizes and TiO 2 facets. Au NPs of ca. 5 nm are more facile undergo Au‐TiO 2 SMSI than those of ca. 2 nm, while TiO 2 {001} and {100} facets are more facile than TiO 2 {101} facets. The resulting capsulating TiO 2− x overlayers on Au NPs exhibit an average oxidation state between +3 and +4 and a Au‐to‐TiO 2− x charge transfer, which, combined with calculations, determines the Ti:O ratio as ca. 6:11. Both TiO 2− x overlayers and TiO 2− x ‐Au interface exhibit easier lattice oxygen activation and higher intrinsic activity in catalyzing low‐temperature CO oxidation than the starting Au‐TiO 2 interface. These results advance fundamental understanding of SMSI and demonstrate engineering of metal NP size and oxide facet as an effective strategy to tune the SMSI for efficient catalysis.

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 in OLEDs.

Abstract Iodine vacancies (V I ) and undercoordinated Pb 2+ 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 V I in perovskite films. A theoretical study shows that HA bonds to the V I 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 Pb 2+ 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 NiFe‐based electrocatalysts have attracted great interests due to the low price and high activity in oxygen evolution reaction (OER). However, the complex reaction mechanism of NiFe‐catalyzed OER has not been fully explored yet. Detection of intermediate species can bridge the gap between OER performances and catalyst component/structure properties. Here, we performed label‐free surface‐enhanced Raman spectroscopic (SERS) monitoring of interfacial OER process on Ni3FeOx nanoparticles (NPs) in alkaline medium. By using bifunctional Au@Ni3FeOx core‐satellite superstructures as Raman signal enhancer, we found direct spectroscopic evidence of intermediate O‐O− species. According to the SERS results, Fe atoms are the catalytic sites for the initial OH− to O‐O− oxidation. The O‐O− species adsorbed across neighboring Fe and Ni sites experiences further oxidation caused by electron transfer to NiIII and eventually forms O2 product.

Abstract Herein, we first design a fast low‐pressure ultraviolet light irradiation strategy for easily regenerating the nearly equivalent surface vacancies. Taking the defective Bi 2 O 2 CO 3 nanosheets as an example, nearly equal amount of oxygen vacancies can be regenerated under UV light irradiation. Synchrotron‐radiation quasi in situ X‐ray photoelectron spectra disclose the Bi sites in the O‐defective Bi 2 O 2 CO 3 nanosheets can act as the highly active sites, which not only help to activate CO 2 molecules, but also contribute to stabilizing the rate‐limiting COOH* intermediate. Also, in situ Fourier transform infrared spectroscopy and in situ mass spectrometry unravel the UV light irradiation contributes to accelerating CO desorption process. As a result, the O‐defective Bi 2 O 2 CO 3 nanosheets achieve a stability up to 2640 h over 110 cycling tests and a high evolution rate of 275 μmol g −1 h −1 for visible‐light‐driven CO 2 reduction to CO.

Abstract Electrocatalytic two‐electron oxygen reduction has emerged as a promising alternative to the energy‐ and waste‐intensive anthraquinone process for distributed H 2 O 2 production. This process, however, suffers from strong competition from the four‐electron pathway leading to low H 2 O 2 selectivity. Herein, we report using a superhydrophilic O 2 ‐entrapping electrocatalyst to enable superb two‐electron oxygen reduction electrocatalysis. The honeycomb carbon nanofibers (HCNFs) are robust and capable of achieving a high H 2 O 2 selectivity of 97.3 %, much higher than that of its solid carbon nanofiber counterpart. Impressively, this catalyst achieves an ultrahigh mass activity of up to 220 A g −1 , surpassing all other catalysts for two‐electron oxygen reduction reaction. The superhydrophilic porous carbon skeleton with rich oxygenated functional groups facilitates efficient electron transfer and better wetting of the catalyst by the electrolyte, and the interconnected cavities allow for more effective entrapping of the gas bubbles. The catalytic mechanism is further revealed…

Abstract The exploitation of highly efficient carbon dioxide reduction (CO 2 RR) electrocatalyst for methane (CH 4 ) 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 CO 2 reduction to CH 4 at −1.5 V vs. RHE with a current density of 420 mA cm −2 . The CH 4 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 CO 2 to 2Bn‐Cu, significantly increasing the availability of each catalytic center.

Abstract Lithium (Li) metal anodes hold great promise for next‐generation high‐energy‐density batteries, while the insufficient fundamental understanding of the complex solid electrolyte interphase (SEI) is the major obstacle for the full demonstration of their potential in working batteries. The characteristics of SEI highly depend on the inner solvation structure of lithium ions (Li+). Herein, we clarify the critical significance of cosolvent properties on both Li+ solvation structure and the SEI formation on working Li metal anodes. Non‐solvating and low‐dielectricity (NL) cosolvents intrinsically enhance the interaction between anion and Li+ by affording a low dielectric environment. The abundant positively charged anion–cation aggregates generated as the introduction of NL cosolvents are preferentially brought to the negatively charged Li anode surface, inducing an anion‐derived inorganic‐rich SEI. A solvent diagram is further built to illustrate that a solvent with both proper relative binding energy toward Li+ and dielectric constant is suitable as NL cosolvent.

Life is a non-equilibrium state of matter maintained at the expense of energy. Nature uses predominantly chemical energy stored in thermodynamically activated, but kinetically stable, molecules. These high-energy molecules are exploited for the synthesis of other biomolecules, for the activation of biological machinery such as pumps and motors, and for the maintenance of structural order. Knowledge of how chemical energy is transferred to biochemical processes is essential for the development of artificial systems with life-like processes. Here, we discuss how chemical energy can be used to control the structural organization of organic molecules. Four different strategies have been identified according to a distinguishable physical-organic basis. For each class, one example from biology and one from chemistry are discussed in detail to illustrate the practical implementation of each concept and the distinct opportunities they offer. Specific attention is paid to the discussion of chemically fueled non-equilibrium self-assembly. We discuss the meaning of non-equilibrium…

Abstract Severe interfacial side reactions of polymer electrolyte with LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and Li metal anode restrict the cycling performance of solid‐state NCM811/Li batteries. Herein, we propose a chemically stable ceramic‐polymer‐anchored solvent composite electrolyte with high ionic conductivity of 6.0×10−4 S cm−1, which enables the solid‐state NCM811/Li batteries to cycle 1500 times. The Li1.4Al0.4Ti1.6(PO4)3 nanowires (LNs) can tightly anchor the essential N, N‐dimethylformamide (DMF) in poly(vinylidene fluoride) (PVDF), greatly enhancing its electrochemical stability and suppressing the side reactions. We identify the ceramic‐polymer‐liquid multiple ion transport mechanism of the LNs‐PVDF‐DMF composite electrolyte by tracking the 6Li and 7Li substitution behavior via solid‐state NMR. The stable interface chemistry and efficient ion transport of LNs‐PVDF‐DMF contribute to superior performances of the solid‐state batteries at wide temperature range of −20–60 °C.

Designing definite metal-support interfacial bond is an effective strategy for optimizing the intrinsic activity of noble metals, but rather challenging. Herein, a series of quantum-sized metal nanoparticles (NPs) anchored on nickel metal-organic framework nanohybrids (M@Ni-MOF, M=Ru, Ir, Pd) are rationally developed through a spontaneous redox strategy. The metal-oxygen bonds between the NPs and Ni-MOF guarantee structural stability and sufficient exposure of the surface active sites. More importantly, such precise interfacial feature can effectively modulate the electronic structure of hybrids through the charge transfer of the formed Ni-O-M bridge and then improves the reaction kinetics. As a result, the representative Ru@Ni-MOF exhibits excellent hydrogen evolution reaction (HER) activity at all pH values, even superior to commercial Pt/C and recent noble-metal catalysts. Theoretical calculations deepen the mechanism understanding of the superior HER performance of Ru@Ni-MOF through the optimized adsorption free energies of water and hydrogen due to the interfacial-bond-induced…

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 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 Herein, we explore a general Cu 2− x S nanocube template‐assisted and reverse cation exchange‐mediated growth strategy for fabricating hollow multinary metal sulfide. Unlike the traditional cation exchange method controlled by the metal sulfide constant, the introduction of tri‐n‐butylphosphine (TBP) can reverse cation exchange to give a series of hollow metal sulfides. A variety of hollow multinary metal sulfide cubic nanostructures has been demonstrated while preserving anisotropic shapes to the as‐synthesized templates, including binary compounds (CdS, ZnS, Ag 2 S, PbS, SnS), ternary compound (CuInS 2 , Zn x Cd 1− x S), and quaternary compound (single‐atom platinum anchored Zn x Cd 1− x S; Zn x Cd 1− x S‐Pt 1 ). Experimental and density functional theory (DFT) calculations show that the hollow metal sulfide semiconductors obtained could significantly improve the separation and migration of photogenerated electron‐hole pairs. Owing to the efficient charge transfer, the Zn x Cd 1− x S‐Pt 1 exhibited outstanding photocatalytic performance of CO 2 to CO, with the highest CO…

Abstract Electrochemical reduction of NO not only offers an attractive alternative to the Haber–Bosch process for ambient NH 3 production but mitigates the human‐caused unbalance of nitrogen cycle. Herein, we report that MoS 2 nanosheet on graphite felt (MoS 2 /GF) acts as an efficient and robust 3D electrocatalyst for NO‐to‐NH 3 conversion. In acidic electrolyte, such MoS 2 /GF attains a maximal Faradaic efficiency of 76.6 % and a large NH 3 yield of up to 99.6 μmol cm −2 h −1 . Using MoS 2 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 NH 3 yield of 411.8 μg h −1 mg cat. −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 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 Near‐infrared (NIR)‐emitting phosphor materials have been extensively developed for optoelectronic and biomedical applications. Although Cr 3+ ‐activated phosphors have been widely reported, it is challenging to achieve ultra‐broad and tunable NIR emission. Here, a new ultra‐broadband NIR‐emitting LiIn 2 SbO 6 :Cr 3+ phosphor with emission peak at 965 nm and a full‐width at half maximum of 217 nm is reported. Controllable emission tuning from 965 to 892 nm is achieved by chemical unit cosubstitution of [Zn 2+ –Zn 2+ ] for [Li + –In 3+ ], which can be ascribed to the upshift of 4 T 2g energy level due to the strengthened crystal field. Moreover, the emission is greatly enhanced, and the FWHM reaches 235 nm. The as‐prepared luminescent tunable NIR‐emitting phosphors have demonstrated the potential in night‐vision and NIR spectroscopy techniques. This work proves the feasibility of chemical unit cosubstitution strategy in emission tuning of Cr 3+ ‐doped phosphors, which can stimulate further studies on the emission‐tunable NIR‐emitting phosphor materials.

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 CO 2 (CO 2 RR) 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 CO 2 RR process. Herein, we re‐survey recent studies with the emphasis on revealing the dynamic chemical state of Cu sites under CO 2 RR conditions extracted by in situ/operando characterizations, and further validate a critical link between the chemical state of Cu and the product profile of CO 2 RR. This point of view provides a generalizable concept of dynamic chemical‐state‐driven CO 2 RR selectivity that offers an inspiration in both fundamental understanding and efficient electrocatalysts design.

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 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 Mg 2+ . The Li + permeation rate through the MXene@PSS composite membrane is as high as 0.08 mol m −2 h −1 , while the Li + /Mg 2+ , 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 (−SO 3 − ) interaction. This study deepens the understanding of ion‐selective permeation in confined channels and provides a general membrane design concept.

Pure organic room-temperature phosphorescence (RTP) materials have attracted wide attention for their easy preparation, low toxicity, and applications in various fields like bioimaging and anti-counterfeiting. Developing phosphorescent systems with more universality and less difficulty in synthesis has long been the pursuit of materials scientists. By employing a polymeric quaternary ammonium salt with an ionic bonding matrix and heavy atoms, commercial fluorescent dyes are directly endowed with phosphorescence emission. In a single amorphous polymer, the external heavy-atom effect generates excited triplet states and the rigid polymer matrix stabilizes them. This study put forward a new general strategy to design and develop pure organic RTP materials starting from existing library of organic dyes without complicated chemical synthesis.

Optical imaging, especially fluorescence and photoacoustic imaging, is a non-invasive imaging approach with high spatial and temporal resolution and high sensitivity, compared to positron emission tomography (PET) or magnetic resonance imaging (MRI). Due to the merits of imaging using the second near-infrared (NIR-II) window, like deeper penetration depth, high signal-to-noise ratio, high resolution, and low tissue damage, researchers have devoted great effort to developing contrast agents with NIR-II absorption or emission. In this Review, we summarize recently developed organic luminescent and photoacoustic materials, ranging from small molecules to conjugated polymers. Then, we systematically introduce engineering strategies and describe the imaging performance classified by the skeleton cores. Finally, we elucidate the challenges and prospects of these NIR-II organic dyes for potential clinical applications. We expect our summary can inspire researchers to expand the spectrum of NIR-II contrast agents for diverse bioapplications.

Pyroptosis as a lytic and inflammatory form of cell death is a powerful tool to fight against cancer. However, pyroptosis is usually activated by chemotherapeutic drugs, which limits its anti-tumor applications due to drug resistance and severe side effects. Herein, we demonstrate that membrane targeting photosensitizers can induce pyroptosis for cancer cell ablation with noninvasiveness and low side effects. A series of membrane anchoring photosensitizers (TBD-R PSs) with aggregation-induced emission (AIE) characteristics were prepared through conjugation of TBD and phenyl ring with cationic chains. Upon light irradiation, cytotoxic ROS were produced in situ, resulting in direct membrane damage and superior cancer cell ablation. Detailed study revealed that pyroptosis gradually became the dominant cell death pathway along with the increase of TBD-R PSs membrane anchoring capability. This study offers a photo-activated pyroptosis-based intervention strategy for cancer cell ablation.

Abstract Electrochemical reduction of carbon dioxide (CO2) into chemicals and fuels has recently attracted much interest, but normally suffers from a high overpotential and low selectivity. In this work, single P atoms were introduced into a N‐doped carbon supported single Fe atom catalyst (Fe‐SAC/NPC) mainly in the form of P−C bonds for CO2 electroreduction to CO in an aqueous solution. This catalyst exhibited a CO Faradaic efficiency of ≈97 % at a low overpotential of 320 mV, and a Tafel slope of only 59 mV dec−1, comparable to state‐of‐the‐art gold catalysts. Experimental analysis combined with DFT calculations suggested that single P atom in high coordination shells (n≥3), in particular the third coordination shell of Fe center enhanced the electronic localization of Fe, which improved the stabilization of the key *COOH intermediate on Fe, leading to superior CO2 electrochemical reduction performance at low overpotentials.

Abstract We reported the selective electrochemical reduction of oxygen (O2) to hydroxyl radicals (.OH) via 3‐electron pathway with FeCo alloy encapsulated by carbon aerogel (FeCoC). The graphite shell with exposed ‐COOH is conducive to the 2‐electron reduction pathway for H2O2generation stepped by 1‐electron reduction towards to.OH. The electrocatalytic activity can be regulated by tuning the local electronic environment of carbon shell with the electrons coming from the inner FeCo alloy. The new strategy of.OH generation from electrocatalytic reduction O2overcomes the rate‐limiting step over electron transfer initiated by reduction‐/oxidation‐state cycle in Fenton process. Fast and complete removal of ciprofloxacin was achieved within 5 min in this proposed system, the apparent rate constant (kobs) was up to 1.44±0.04 min−1, which is comparable with the state‐of‐the‐art advanced oxidation processes. The degradation rate almost remains the same after 50 successive runs, suggesting the satisfactory stability for practical applications.

Abstract The construction of single‐atom catalysts (SACs) with high single atom densities, favorable electronic structures and fast mass transfer is highly desired. We have utilized metal‐triazolate (MET) frameworks, a subclass of metal–organic frameworks (MOFs) with high N content, as precursors since they can enhance the density and regulate the electronic structure of single‐atom sites, as well as generate abundant mesopores simultaneously. Fe single atoms dispersed in a hierarchically porous N‐doped carbon matrix with high metal content (2.78 wt %) and a FeN 4 Cl 1 configuration (FeN 4 Cl 1 /NC), as well as mesopores with a pore:volume ratio of 0.92, were obtained via the pyrolysis of a Zn/Fe‐bimetallic MET modified with 4,5‐dichloroimidazole. FeN 4 Cl 1 /NC exhibits excellent oxygen reduction reaction (ORR) activity in both alkaline and acidic electrolytes. Density functional theory calculations confirm that Cl can optimize the adsorption free energy of Fe sites to *OH, thereby promoting the ORR process. The catalyst demonstrates great potential in zinc‐air batteries. This…