The 100 most-cited articles in Angewandte Chemie International Edition, 2017

Mobile and stationary energy storage by rechargeable batteries is a topic of broad societal and economical relevance. Lithium-ion battery (LIB) technology is at the forefront of the development, but a massively growing market will likely put severe pressure on resources and supply chains. Recently, sodium-ion batteries (SIBs) have been reconsidered with the aim of providing a lower-cost alternative that is less susceptible to resource and supply risks. On paper, the replacement of lithium by sodium in a battery seems straightforward at first, but unpredictable surprises are often found in practice. What happens when replacing lithium by sodium in electrode reactions? This review provides a state-of-the art overview on the redox behavior of materials when used as electrodes in lithium-ion and sodium-ion batteries, respectively. Advantages and challenges related to the use of sodium instead of lithium are discussed.

Abstract The development of low‐cost, efficient, and stable electrocatalysts for the oxygen reduction reaction (ORR) is desirable but remains a great challenge. Herein, we made a highly reactive and stable isolated single‐atom Fe/N‐doped porous carbon (ISA Fe/CN) catalyst with Fe loading up to 2.16 wt %. The catalyst showed excellent ORR performance with a half‐wave potential ( E 1/2 ) of 0.900 V, which outperformed commercial Pt/C and most non‐precious‐metal catalysts reported to date. Besides exceptionally high kinetic current density ( J k ) of 37.83 mV cm −2 at 0.85 V, it also had a good methanol tolerance and outstanding stability. Experiments demonstrated that maintaining the Fe as isolated atoms and incorporating nitrogen was essential to deliver the high performance. First principle calculations further attributed the high reactivity to the high efficiency of the single Fe atoms in transporting electrons to the adsorbed OH species.

The activation strain or distortion/interaction model is a tool to analyze activation barriers that determine reaction rates. For bimolecular reactions, the activation energies are the sum of the energies to distort the reactants into geometries they have in transition states plus the interaction energies between the two distorted molecules. The energy required to distort the molecules is called the activation strain or distortion energy. This energy is the principal contributor to the activation barrier. The transition state occurs when this activation strain is overcome by the stabilizing interaction energy. Following the changes in these energies along the reaction coordinate gives insights into the factors controlling reactivity. This model has been applied to reactions of all types in both organic and inorganic chemistry, including substitutions and eliminations, cycloadditions, and several types of organometallic reactions.

The hydrogen evolution reaction (HER) is a fundamental process in electrocatalysis and plays an important role in energy conversion for the development of hydrogen-based energy sources. However, the considerably slow rate of the HER in alkaline conditions has hindered advances in water splitting techniques for high-purity hydrogen production. Differing from well documented acidic HER, the mechanistic aspects of alkaline HER are yet to be settled. A critical appraisal of alkaline HER electrocatalysis is presented, with a special emphasis on the connection between fundamental surface electrochemistry on single-crystal models and the derived molecular design principle for real-world electrocatalysts. By presenting some typical examples across theoretical calculations, surface characterization, and electrochemical experiments, we try to address some key ongoing debates to deliver a better understanding of alkaline HER at the atomic level.

Recent years have witnessed a dramatic increase in the production of sustainable and renewable energy. However, the electrochemical performances of the various systems are limited, and there is an intensive search for highly efficient electrocatalysts by more rational control over the size, shape, composition, and structure. Of particular interest are the studies on single-atom catalysts (SACs), which have sparked new interests in electrocatalysis because of their high catalytic activity, stability, selectivity, and 100 % atom utilization. In this Review, we introduce innovative syntheses and characterization techniques for SACs, with a focus on their electrochemical applications in the oxygen reduction/evolution reaction, hydrogen evolution reaction, and hydrocarbon conversion reactions for fuel cells (electrooxidation of methanol, ethanol, and formic acid). The electrocatalytic performance is further considered at an atomic level and the underlying mechanisms are discussed. The ultimate goal is the tailoring of single atoms for electrochemical applications.

Lithium (Li) metal is the most promising electrode for next-generation rechargeable batteries. However, the challenges induced by Li dendrites on a working Li metal anode hinder the practical applications of Li metal batteries. Herein, nitrogen (N) doped graphene was adopted as the Li plating matrix to regulate Li metal nucleation and suppress dendrite growth. The N-containing functional groups, such as pyridinic and pyrrolic nitrogen in the N-doped graphene, are lithiophilic, which guide the metallic Li nucleation causing the metal to distribute uniformly on the anode surface. As a result, the N-doped graphene modified Li metal anode exhibits a dendrite-free morphology during repeated Li plating and demonstrates a high Coulombic efficiency of 98 % for near 200 cycles.

Semiconductor photocatalysis is a trustworthy approach to harvest clean solar light for energy conversions, while state-of-the-art catalytic efficiencies are unsatisfactory because of the finite light response and/or recombination of robust charge carriers. Along with the development of modern material characterization techniques and electronic-structure computations, oxygen vacancies (OVs) on the surface of real photocatalysts, even in infinitesimal concentration, are found to play a more decisive role in determining the kinetics, energetics, and mechanisms of photocatalytic reactions. This Review endeavors to clarify the inherent functionality of OVs in photocatalysis at the surface molecular level using 2D BiOCl as the platform. Structure sensitivity of OVs on reactivity and selectivity of photocatalytic reactions is intensely discussed via confining OVs onto prototypical BiOCl surfaces of different structures. The critical understanding of OVs chemistry can help consolidate and advance the fundamental theories of photocatalysis, and also offer new perspectives and guidelines for…

Tailor-made: Discussed herein is the ability to adapt biology's mechanisms for innovation and optimization to solving problems in chemistry and engineering. The evolution of nature's enzymes can lead to the discovery of new reactivity, transformations not known in biology, and reactivity inaccessible by small-molecule catalysts.

Abstract The design of active, selective, and stable CO2 reduction electrocatalysts is still challenging. A series of atomically dispersed Co catalysts with different nitrogen coordination numbers were prepared and their CO2 electroreduction catalytic performance was explored. The best catalyst, atomically dispersed Co with two‐coordinate nitrogen atoms, achieves both high selectivity and superior activity with 94 % CO formation Faradaic efficiency and a current density of 18.1 mA cm−2 at an overpotential of 520 mV. The CO formation turnover frequency reaches a record value of 18 200 h−1, surpassing most reported metal‐based catalysts under comparable conditions. Our experimental and theoretical results demonstrate that lower a coordination number facilitates activation of CO2 to the CO2.− intermediate and hence enhances CO2 electroreduction activity.

Abstract Two‐dimensional (2D) materials are promising candidates for advanced water purification membranes. A new kind of lamellar membrane is based on a stack of 2D MXene nanosheets. Starting from compact Ti 3 AlC 2 , delaminated nanosheets of the composition Ti 3 C 2 T x with the functional groups T (O, OH, and/or F) can be produced by etching and ultrasonication and stapled on a porous support by vacuum filtration. The MXene membrane supported on anodic aluminum oxide (AAO) substrate shows excellent water permeance (more than 1000 L m −2 h −1 bar −1 ) and favorable rejection rate (over 90 %) for molecules with sizes larger than 2.5 nm. The water permeance through the MXene membrane is much higher than that of the most membranes with similar rejections. Long‐time operation also reveals the outstanding stability of the MXene membrane for water purification.

Abstract Abstraction of a chloride ligand from the dysprosium metallocene [(Cp ttt ) 2 DyCl] ( 1 Dy Cp ttt =1,2,4‐tri( tert ‐butyl)cyclopentadienide) by the triethylsilylium cation produces the first base‐free rare‐earth metallocenium cation [(Cp ttt ) 2 Dy] + ( 2 Dy ) as a salt of the non‐coordinating [B(C 6 F 5 ) 4 ] − anion. Magnetic measurements reveal that [ 2 Dy ][B(C 6 F 5 ) 4 ] is an SMM with a record anisotropy barrier up to 1277 cm −1 (1837 K) in zero field and a record magnetic blocking temperature of 60 K, including hysteresis with coercivity. The exceptional magnetic axiality of 2 Dy is further highlighted by computational studies, which reveal this system to be the first lanthanide SMM in which all low‐lying Kramers doublets correspond to a well‐defined M J value, with no significant mixing even in the higher doublets.

Abstract The gradually increased concentration of carbon dioxide (CO2) in the atmosphere has been recognized as the primary culprit for the rise of the global mean temperature. In recent years, development of routes for highly efficient conversion of CO2 has received much attention. This Review describes recent progress on the design and synthesis of solid‐state catalysts for the electrochemical reduction of CO2. The significance of this catalytic conversion is presented, followed by the general parameters for CO2 electroreduction and a summary of the reaction apparatus. We also discuss various types of solid catalysts based on their CO2 conversion mechanisms. We summarize the crucial factors (particle size, surface structure, composition, etc.) determining the performance for electroreduction.

Abstract Efficient photo‐ and piezoelectric‐induced molecular oxygen activation are both achieved by macroscopic polarization enhancement on a noncentrosymmetric piezoelectric semiconductor BiOIO3. The replacement of V5+ions for I5+in IO3polyhedra gives rise to strengthened macroscopic polarization of BiOIO3, which facilitates the charge separation in the photocatalytic and piezoelectric catalytic process, and renders largely promoted photo‐ and piezoelectric induced reactive oxygen species (ROS) evolution, such as superoxide radicals (.O2−) and hydroxyl radicals (.OH). This work advances piezoelectricity as a new route to efficient ROS generation, and also discloses macroscopic polarization engineering on improvement of multi‐responsive catalysis.

Chemistry welcomes a new bond: The mechanical bond has endowed molecules with component parts whose movements can be controlled and monitored. In his Nobel Lecture, J. F. Stoddart describes how being able to template the formation of mechanically interlocked molecules has led to the design and synthesis of shuttles, switches, and machines at the nanoscale.

Layered double hydroxides (LDHs) with two-dimensional lamellar structures show excellent electrocatalytic properties. However, the catalytic activity of LDHs needs to be further improved as the large lateral size and thickness of the bulk material limit the number of exposed active sites. However, the development of efficient strategies to exfoliate bulk LDHs into stable monolayer LDH nanosheets with more exposed active sites is very challenging. On the other hand, the intrinsic activity of monolayer LDH nanosheets can be tuned by surface engineering. Herein, we have exfoliated bulk CoFe LDHs into ultrathin LDH nanosheets through Ar plasma etching, which also resulted in the formation of multiple vacancies (including O, Co, and Fe vacancies) in the ultrathin 2D nanosheets. Owing to their ultrathin 2D structure, the LDH nanosheets expose a greater number of active sites, and the multiple vacancies significantly improve the intrinsic activity in the oxygen evolution reaction (OER).

Nonribosomal peptide synthetases (NRPSs) are large multienzyme machineries that assemble numerous peptides with large structural and functional diversity. These peptides include more than 20 marketed drugs, such as antibacterials (penicillin, vancomycin), antitumor compounds (bleomycin), and immunosuppressants (cyclosporine). Over the past few decades biochemical and structural biology studies have gained mechanistic insights into the highly complex assembly line of nonribosomal peptides. This Review provides state-of-the-art knowledge on the underlying mechanisms of NRPSs and the variety of their products along with detailed analysis of the challenges for future reprogrammed biosynthesis. Such a reprogramming of NRPSs would immediately spur chances to generate analogues of existing drugs or new compound libraries of otherwise nearly inaccessible compound structures.

Abstract The discovery of new nonlinear optical (NLO) materials for coherent light generation in the deep‐ultraviolet (DUV, wavelength below 200 nm) region is essential for the development of laser technologies. Herein, we report a new material CsB4O6F (CBF), which combines the superior structural properties of two well‐known NLO materials, β‐BaB2O4 (BBO) and KBe2BO3F2 (KBBF). CBF exhibits excellent DUV optical properties including a short cutoff edge (155 nm), a large SHG response (≈1.9×KDP), and a suitable birefringence that enables frequency doubling down to 171.6 nm. Remarkably, CBF melts congruently and shows an improved growth habit. In addition, our rational design strategy will contribute to the discovery of DUV NLO materials.

Abstract Deep‐ultraviolet nonlinear optical (DUV NLO) crystals are the key materials to extend the output range of solid‐state lasers to below 200 nm. The only practical material KBe2BO3F2 suffers high toxicity through beryllium and strong layered growth. Herein, we propose a beryllium‐free material design and synthesis strategy for DUV NLO materials. Introducing the (BO3F)4−, (BO2F2)3−, and (BOF3)2− groups in borates could break through the fixed 3D B–O network that would produce a larger birefringence without layering and simultaneously keep a short cutoff edge down to DUV. The theoretical and experimental studies on a series of fluorooxoborates confirm this strategy. Li2B6O9F2 is identified as a DUV NLO material with a large second harmonic generation efficiency (0.9×KDP) and a large predicted birefringence (0.07) without layering. This study provides a feasible way to break down the DUV wall for NLO materials.

Hollow nanostructures have attracted increasing research interest in electrochemical energy storage and conversion owing to their unique structural features. However, the synthesis of hollow nanostructured metal phosphides, especially nonspherical hollow nanostructures, is rarely reported. Herein, we develop a metal-organic framework (MOF)-based strategy to synthesize carbon incorporated Ni-Co mixed metal phosphide nanoboxes (denoted as NiCoP/C). The oxygen evolution reaction (OER) is selected as a demonstration to investigate the electrochemical performance of the NiCoP/C nanoboxes. For comparison, Ni-Co layered double hydroxide (Ni-Co LDH) and Ni-Co mixed metal phosphide (denoted as NiCoP) nanoboxes have also been synthesized. Benefiting from their structural and compositional merits, the as-synthesized NiCoP/C nanoboxes exhibit excellent electrocatalytic activity and long-term stability for OER.

To a large extent, the field of "molecular machines" started after several groups were able to prepare, reasonably easily, interlocking ring compounds (named catenanes for compounds consisting of interlocking rings and rotaxanes for rings threaded by molecular filaments or axes). Important families of molecular machines not belonging to the interlocking world were also designed, prepared, and studied but, for most of them, their elaboration was more recent than that of catenanes or rotaxanes. Since the creation of interlocking ring molecules is so important in relation to the molecular machinery area, we will start with this aspect of our work. The second part will naturally be devoted to the dynamic properties of such systems and to the compounds for which motions can be directed in a controlled manner from the outside, that is, molecular machines. We will restrict our discussion to a very limited number of examples which we consider as particularly representative of the field.

Abstract Hydrogen isotopes are unique tools for identifying and understanding biological and chemical processes. Hydrogen isotope labelling allows for the traceless and direct incorporation of an additional mass or radioactive tag into an organic molecule with almost no changes in its chemical structure, physical properties, or biological activity. Using deuterium‐labelled isotopologues to study the unique mass‐spectrometric patterns generated from mixtures of biologically relevant molecules drastically simplifies analysis. Such methods are now providing unprecedented levels of insight in a wide and continuously growing range of applications in the life sciences and beyond. Tritium ( 3 H), in particular, has seen an increase in utilization, especially in pharmaceutical drug discovery. The efforts and costs associated with the synthesis of labelled compounds are more than compensated for by the enhanced molecular sensitivity during analysis and the high reliability of the data obtained. In this Review, advances in the application of hydrogen isotopes in the life sciences are…

Abstract The design of narrow band gap (NBG) donors or acceptors and their application in organic solar cells (OSCs) are of great importance in the conversion of solar photons to electrons. Limited by the inevitable energy loss from the optical band gap of the photovoltaic material to the open‐circuit voltage of the OSC device, the improvement of the power conversion efficiency (PCE) of NBG‐based OSCs faces great challenges. A novel acceptor–donor–acceptor structured non‐fullerene acceptor is reported with an ultra‐narrow band gap of 1.24 eV, which was achieved by an enhanced intramolecular charge transfer (ICT) effect. In the OSC device, despite a low energy loss of 0.509 eV, an impressive short‐circuit current density of 25.3 mA cm −2 is still recorded, which is the highest value for all OSC devices. The high 10.9 % PCE of the NBG‐based OSC demonstrates that the design and application of ultra‐narrow materials have the potential to further improve the PCE of OSC devices.

Research into extended porous materials such as metal-organic frameworks (MOFs) and porous organic frameworks (POFs), as well as the analogous metal-organic polyhedra (MOPs) and porous organic cages (POCs), has blossomed over the last decade. Given their chemical and structural variability and notable porosity, MOFs have been proposed as adsorbents for industrial gas separations and also as promising filler components for high-performance mixed-matrix membranes (MMMs). Research in this area has focused on enhancing the chemical compatibility of the MOF and polymer phases by judiciously functionalizing the organic linkers of the MOF, modifying the MOF surface chemistry, and, more recently, exploring how particle size, morphology, and distribution enhance separation performance. Other filler materials, including POFs, MOPs, and POCs, are also being explored as additives for MMMs and have shown remarkable anti-aging performance and excellent chemical compatibility with commercially available polymers. This Review briefly outlines the state-of-the-art in MOF-MMM fabrication, and the…

Discovered in 2005, cyclic (alkyl)(amino)carbenes (CAACs) are among the most nucleophilic (σ donating) and also electrophilic (π-accepting) stable carbenes known to date. These properties allow them to activate a variety of small molecules and enthalpically strong bonds, to stabilize highly reactive main-group and transition-metal diamagnetic and paramagnetic species, and to bind strongly to metal centers, which gives rise to very robust catalysts. The most important results published up to the end of 2013 are briefly summarized, while the majority of this Review focuses on findings reported within the last three years.

Despite the large number of disparate approaches for the direct selective partial oxidation of methane, none of them has translated into an industrial process. The oxidation of methane to methanol is a difficult, but intriguing and rewarding, task as it has the potential to eliminate the prevalent natural gas flaring by providing novel routes to its valorization. This Review considers the synthesis of methanol and methanol derivatives from methane by homogeneous and heterogeneous pathways. By establishing the severe limitations related to the direct catalytic synthesis of methanol from methane, we highlight the vastly superior performance of systems which produce methanol derivatives or incorporate specific measures, such as the use of multicomponent catalysts to stabilize methanol. We thereby identify methanol protection as being indispensable for future research on homogeneous and heterogeneous catalysis.

Abstract The nanostructure of a series of choline chloride/urea/water deep eutectic solvent mixtures was characterized across a wide hydration range by neutron total scattering and empirical potential structure refinement (EPSR). As the structure is significantly altered, even at low hydration levels, reporting the DES water content is important. However, the DES nanostructure is retained to a remarkably high level of water (ca. 42 wt % H 2 O) because of solvophobic sequestration of water into nanostructured domains around cholinium cations. At 51 wt %/83 mol % H 2 O, this segregation becomes unfavorable, and the DES structure is disrupted; instead, water–water and DES–water interactions dominate. At and above this hydration level, the DES–water mixture is best described as an aqueous solution of DES components.

A journey into the nano-world: The ability to design, use and control motor-like functions at the molecular level sets the stage for numerous dynamic molecular systems. In his Nobel Lecture, B. L. Feringa describes the evolution of the field of molecular motors and explains how to program and control molecules by incorporating responsive and adaptive properties.

Metal-catalyzed cross-coupling reactions belong to the most important transformations in organic synthesis. Copper catalysis has received great attention owing to the low toxicity and low cost of copper. However, traditional Ullmann-type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of several bidentate ligands, such as amino acids, diamines, 1,3-diketones, and oxalic diamides, over the past two decades has totally changed this situation as these ligands enable the copper-catalyzed coupling of aryl halides and nucleophiles at both low reaction temperatures and catalyst loadings. The reaction scope has also been greatly expanded, rendering this copper-based cross-coupling attractive for both academia and industry. In this Review, we have summarized the latest progress in the development of useful reaction conditions for the coupling of (hetero)aryl halides with different nucleophiles. Additionally, recent advances in copper-catalyzed coupling reactions with aryl boronates and the copper-based trifluoromethylation of aromatic…

Abstract Polymeric or organic semiconductors are promising candidates for photocatalysis but mostly only show moderate activity owing to strongly bound excitons and insufficient optical absorption. Herein, we report a facile bottom‐up strategy to improve the activity of a carbon nitride to a level in which a majority of photons are really used to drive photoredox chemistry. Co‐condensation of urea and oxamide followed by post‐calcination in molten salt is shown to result in highly crystalline species with a maximum π–π layer stacking distance of heptazine units of 0.292 nm, which improves lateral charge transport and interlayer exciton dissociation. The addition of oxamide decreases the optical band gap from 2.74 to 2.56 eV, which enables efficient photochemistry also with green light. The apparent quantum yield (AQY) for H2 evolution of optimal samples reaches 57 % and 10 % at 420 nm and 525 nm, respectively, which is significantly higher than in most previous experiments.

Abstract Conductive hydrogels are a class of stretchable conductive materials that are important for various applications. However, water‐based conductive hydrogels inevitably lose elasticity and conductivity at subzero temperatures, which severely limits their applications at low temperatures. Herein we report anti‐freezing conductive organohydrogels by using an H 2 O/ethylene glycol binary solvent as dispersion medium. Owing to the freezing tolerance of the binary solvent, our organohydrogels exhibit stable flexibility and strain‐sensitivity in the temperature range from −55.0 to 44.6 °C. Meanwhile, the solvent molecules could form hydrogen bonds with polyvinyl alcohol (PVA) chains and induce the crystallization of PVA, greatly improving the mechanical strength of the organohydrogels. Furthermore, the non‐covalent crosslinks endow the conductive organohydrogels with intriguing remoldability and self‐healing capability, which are important for practical applications.

Lithium (Li) metal is a promising anode material for high-energy density batteries. However, the unstable and static solid electrolyte interphase (SEI) can be destroyed by the dynamic Li plating/stripping behavior on the Li anode surface, leading to side reactions and Li dendrites growth. Herein, we design a smart Li polyacrylic acid (LiPAA) SEI layer high elasticity to address the dynamic Li plating/stripping processes by self-adapting interface regulation, which is demonstrated by in situ AFM. With the high binding ability and excellent stability of the LiPAA polymer, the smart SEI can significantly reduce the side reactions and improve battery safety markedly. Stable cycling of 700 h is achieved in the LiPAA-Li/LiPAA-Li symmetrical cell. The innovative strategy of self-adapting SEI design is broadly applicable, providing opportunities for use in Li metal anodes.

Modern simulation techniques have reached a level of maturity which allows a wide range of problems in chemistry and materials science to be addressed. Unfortunately, the application of first principles methods with predictive power is still limited to rather small systems, and despite the rapid evolution of computer hardware no fundamental change in this situation can be expected. Consequently, the development of more efficient but equally reliable atomistic potentials to reach an atomic level understanding of complex systems has received considerable attention in recent years. A promising new development has been the introduction of machine learning (ML) methods to describe the atomic interactions. Once trained with electronic structure data, ML potentials can accelerate computer simulations by several orders of magnitude, while preserving quantum mechanical accuracy. This Review considers the methodology of an important class of ML potentials that employs artificial neural networks.

Abstract The functionalization of C(sp 3 )−H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C−H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C−H activation, 1, n ‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp 3 )−H bonds. For each strategy, the scope, the reactivity of different C−H bonds, the position of the reacting C−H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C−H functionalization reactions and inspire future research in this area.

Abstract Highly active, stable, and cheap Pt‐free catalysts for the hydrogen evolution reaction (HER) are under increasing demand for future energy conversion systems. However, developing HER electrocatalysts with Pt‐like activity that can function at all pH values still remains as a great challenge. Herein, based on our theoretical predictions, we design and synthesize a novel N,P dual‐doped carbon‐encapsulated ruthenium diphosphide (RuP2@NPC) nanoparticle electrocatalyst for HER. Electrochemical tests reveal that, compared with the Pt/C catalyst, RuP2@NPC not only has Pt‐like HER activity with small overpotentials at 10 mA cm−2 (38 mV in 0.5 m H2SO4, 57 mV in 1.0 m PBS and 52 mV in 1.0 m KOH), but demonstrates superior stability at all pH values, as well as 100 % Faradaic yields. Therefore, this work adds to the growing family of transition‐metal phosphides/heteroatom‐doped carbon heterostructures with advanced performance in HER.

Abstract Nanomaterials with enzyme‐like activities (nanozymes) attracts significant interest due to their therapeutic potential for the treatment of various diseases. Herein, we report that a Mn 3 O 4 nanozyme functionally mimics three major antioxidant enzymes, that is, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and the multienzyme activity is size as well as morphology‐dependent. The redox modulatory effect of Mn 3 O 4 plays a crucial role in protecting the cells from MPP+ induced cytotoxicity in a Parkinson disease (PD)‐like cellular model, indicating that manganese‐based nanomaterials having multi‐enzyme activity can robustly rescue the cells from oxidative damage and thereby possess therapeutic potential to prevent ROS‐mediated neurological disorders.

Abstract Methanol synthesis by CO 2 hydrogenation is a key process in a methanol‐based economy. This reaction is catalyzed by supported copper nanoparticles and displays strong support or promoter effects. Zirconia is known to enhance both the methanol production rate and the selectivity. Nevertheless, the origin of this observation and the reaction mechanisms associated with the conversion of CO 2 to methanol still remain unknown. A mechanistic study of the hydrogenation of CO 2 on Cu/ZrO 2 is presented. Using kinetics, in situ IR and NMR spectroscopies, and isotopic labeling strategies, surface intermediates evolved during CO 2 hydrogenation were observed at different pressures. Combined with DFT calculations, it is shown that a formate species is the reaction intermediate and that the zirconia/copper interface is crucial for the conversion of this intermediate to methanol.

Abstract Lead‐based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead‐based and the other is the poor stability. Lead‐free all‐inorganic perovskite Cs 3 Bi 2 X 9 (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560 nm synthesized by a facile room temperature reaction. The ligand‐free Cs 3 Bi 2 Br 9 NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2 %. The PLQE can be increased to 4.5 % when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2–20 ps). Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30 days.

Abstract The utility of electronically conductive metal–organic frameworks (EC‐MOFs) in high‐performance devices has been limited to date by a lack of high‐quality thin film. The controllable thin‐film fabrication of an EC‐MOF, Cu3(HHTP)2, (HHTP=2,3,6,7,10,11‐hexahydroxytriphenylene), by a spray layer‐by‐layer liquid‐phase epitaxial method is reported. The Cu3(HHTP)2 thin film can not only be precisely prepared with thickness increment of about 2 nm per growing cycle, but also shows a smooth surface, good crystallinity, and high orientation. The chemiresistor gas sensor based on this high‐quality thin film is one of the best room‐temperature sensors for NH3 among all reported sensors based on various materials.

Abstract Metal–organic frameworks (MOFs) are a class of promising materials for diverse heterogeneous catalysis, but they are usually not directly employed for oxygen evolution electrocatalysis. Most reports focus on using MOFs as templates to in situ create efficient electrocatalysts through annealing. Herein, we prepared a series of Fe/Ni‐based trimetallic MOFs (Fe/Ni/Co(Mn)‐MIL‐53 accordingly to the Material of Institute Lavoisier) by solvothermal synthesis, which can be directly adopted as highly efficient electrocatalysts. The Fe/Ni/Co(Mn)‐MIL‐53 shows a volcano‐type oxygen evolution reaction (OER) activity as a function of compositions. The optimized Fe/Ni2.4/Co0.4‐MIL‐53 can reach a current density of 20 mA cm−2 at low overpotential of 236 mV with a small Tafel slope of 52.2 mV dec−1. In addition, the OER performance of these MOFs can be further enhanced by directly being grown on nickel foam (NF).

Abstract Covalent triazine frameworks (CTFs) are normally synthesized by ionothermal methods. The harsh synthetic conditions and associated limited structural diversity do not benefit for further development and practical large‐scale synthesis of CTFs. Herein we report a new strategy to construct CTFs (CTF‐HUSTs) via a polycondensation approach, which allows the synthesis of CTFs under mild conditions from a wide array of building blocks. Interestingly, these CTFs display a layered structure. The CTFs synthesized were also readily scaled up to gram quantities. The CTFs are potential candidates for separations, photocatalysis and for energy storage applications. In particular, CTF‐HUSTs are found to be promising photocatalysts for sacrificial photocatalytic hydrogen evolution with a maximum rate of 2647 μmol h −1 g −1 under visible light. We also applied a pyrolyzed form of CTF‐HUST‐4 as an anode material in a sodium‐ion battery achieving an excellent discharge capacity of 467 mAh g −1 .

Carbon dioxide and carbon monoxide can be electrochemically reduced to useful products such as ethylene and ethanol on copper electrocatalysts. The process is yet to be optimized and the exact mechanism and the corresponding reaction intermediates are under debate or unknown. In particular, it has been hypothesized that the C-C bond formation proceeds via CO dimerization and further hydrogenation. Although computational support for this hypothesis exists, direct experimental evidence has been elusive. In this work, we detect a hydrogenated dimer intermediate (OCCOH) using Fourier transform infrared spectroscopy at low overpotentials in LiOH solutions. Density functional theory calculations support our assignment of the observed vibrational bands. The formation of this intermediate is structure sensitive, as it is observed only during CO reduction on Cu(100) and not on Cu(111), in agreement with previous experimental and computational observations.

Abstract Ammonia is synthesized directly from water and N2 at room temperature and atmospheric pressure in a flow electrochemical cell operating in gas phase (half‐cell for the NH3 synthesis). Iron supported on carbon nanotubes (CNTs) was used as the electrocatalyst in this half‐cell. A rate of ammonia formation of 2.2×10−3 g m−2 h−1 was obtained at room temperature and atmospheric pressure in a flow of N2, with stable behavior for at least 60 h of reaction, under an applied potential of −2.0 V. This value is higher than the rate of ammonia formation obtained using noble metals (Ru/C) under comparable reaction conditions. Furthermore, hydrogen gas with a total Faraday efficiency as high as 95.1 % was obtained. Data also indicate that the active sites in NH3 electrocatalytic synthesis may be associated to specific carbon sites formed at the interface between iron particles and CNT and able to activate N2, making it more reactive towards hydrogenation.

Abstract Spontaneously solar‐driven water splitting to produce H 2 and O 2 , that is, the conversion of solar energy to chemical energy is a dream of mankind. However, it is difficult to make overall water splitting feasible without using any sacrificial agents and external bias. Drawing inspiration from nature, a new artificial Z‐scheme photocatalytic system has been designed herein based on the two‐dimensional (2D) heterostructure of black phosphorus (BP)/bismuth vanadate (BiVO 4 ). An effective charge separation makes possible the reduction and oxidation of water on BP and BiVO 4 , respectively. The optimum H 2 and O 2 production rates on BP/BiVO 4 were approximately 160 and 102 μmol g −1 h −1 under irradiation of light with a wavelength longer than 420 nm, without using any sacrificial agents or external bias.

Persistent room-temperature phosphorescence (RTP) in pure organic materials has attracted great attention because of their unique optical properties. The design of organic materials with bright red persistent RTP remains challenging. Herein, we report a new design strategy for realizing high brightness and long lifetime of red-emissive RTP molecules, which is based on introducing an alkoxy spacer between the hybrid units in the molecule. The spacer offers easy Br-H bond formation during crystallization, which also facilitates intermolecular electron coupling to favor persistent RTP. As the majority of RTP compounds have to be confined in a rigid environment to quench nonradiative relaxation pathways for bright phosphorescence emission, nanocrystallization is used to not only rigidify the molecules but also offer the desirable size and water-dispersity for biomedical applications.

The oxygen evolution reaction (OER) is involved in various renewable energy systems, such as water-splitting cells and metal-air batteries. Ni-Fe layered double hydroxides (LDHs) have been reported as promising OER electrocatalysts in alkaline electrolytes. The rational design of advanced nanostructures for Ni-Fe LDHs is highly desirable to optimize their electrocatalytic performance. Herein, we report a facile self-templated strategy for the synthesis of novel hierarchical hollow nanoprisms composed of ultrathin Ni-Fe LDH nanosheets. Tetragonal nanoprisms of nickel precursors were first synthesized as the self-sacrificing template. Afterwards, these Ni precursors were consumed during the hydrolysis of iron(II) sulfate for the simultaneous growth of a layer of Ni-Fe LDH nanosheets on the surface. The resultant Ni-Fe LDH hollow prisms with large surface areas manifest high electrocatalytic activity towards the OER with low overpotential, small Tafel slope, and remarkable stability.

Abstract All‐polymer solar cells (all‐PSCs) offer unique morphology stability for the application as flexible devices, but the lack of high‐performance polymer acceptors limits their power conversion efficiency (PCE) to a value lower than those of the PSCs based on fullerene derivative or organic small molecule acceptors. We herein demonstrate a strategy to synthesize a high‐performance polymer acceptor PZ1 by embedding an acceptor–donor–acceptor building block into the polymer main chain. PZ1 possesses broad absorption with a low band gap of 1.55 eV and high absorption coefficient (1.3×105 cm−1). The all‐PSCs with the wide‐band‐gap polymer PBDB‐T as donor and PZ1 as acceptor showed a record‐high PCE of 9.19 % for the all‐PSCs. The success of our polymerization strategy can provide a new way to develop efficient polymer acceptors for all‐PSCs.

The sustainable use of the resources on our planet is essential. Noble metals are very rare and are diversely used in key technologies, such as catalysis. Manganese is the third most abundant transition metal of the Earth's crust and based on the recently discovered impressive reactivity in hydrogenation and dehydrogenation reactions, is a potentially useful noble-metal "replacement". The hope of novel selectivity profiles, not possible with noble metals, is also an aim of such a "replacement". The reactivity of manganese complexes in (de)hydrogenation reactions was demonstrated for the first time in 2016. Herein, we summarize the work that has been published since then and especially discuss the importance of homogeneous manganese catalysts in comparison to cobalt and iron catalysts.

Abstract The lithium–sulfur (Li–S) battery is a promising high‐energy‐density storage system. The strong anchoring of intermediates is widely accepted to retard the shuttle of polysulfides in a working battery. However, the understanding of the intrinsic chemistry is still deficient. Inspired by the concept of hydrogen bond, herein we focus on the Li bond chemistry in Li–S batteries through sophisticated quantum chemical calculations, in combination with 7Li nuclear magnetic resonance (NMR) spectroscopy. Identified as Li bond, the strong dipole–dipole interaction between Li polysulfides and Li–S cathode materials originates from the electron‐rich donors (e.g., pyridinic nitrogen (pN)), and is enhanced by the inductive and conjugative effect of scaffold materials with π‐electrons (e.g., graphene). The chemical shift of Li polysulfides in 7Li NMR spectroscopy, being both theoretically predicted and experimentally verified, is suggested to serve as a quantitative descriptor of Li bond strength. These theoretical insights were further proved by actual electrochemical tests. This work…

Abstract A wide range of light absorption and rapid electron–hole separation are desired for efficient photocatalysis. Herein, on the basis of a semiconductor‐like metal–organic framework (MOF), a Pt@MOF/Au catalyst with two types of metal–MOF interfaces integrates the surface plasmon resonance excitation of Au nanorods with a Pt‐MOF Schottky junction, which not only extends the light absorption of the MOF from the UV to the visible region but also greatly accelerates charge transfer. The spatial separation of Pt and Au particles by the MOF further steers the formation of charge flow and expedites the charge migration. As a result, the Pt@MOF/Au presents an exceptionally high photocatalytic H2 production rate by water splitting under visible light irradiation, far superior to Pt/MOF/Au, MOF/Au and other counterparts with similar Pt or Au contents, highlighting the important role of each component and the Pt location in the catalyst.

Abstract Hollow structures with an efficient light harvesting and tunable interior component offer great advantages for constructing a Z‐scheme system. Controlled design of hollow cobalt sulfide (Co9S8) cubes embedded with cadmium sulfide quantum dots (QDs) is described, using hollow Co(OH)2 as the template and a one‐pot hydrothermal strategy. The hollow CdS/Co9S8 cubes utilize multiple reflections of light in the cubic structure to achieve enhanced photocatalytic activity. Importantly, the photoexcited charge carriers can be effectively separated by the construction of a redox‐mediator‐free Z‐scheme system. The hydrogen evolution rate over hollow CdS/Co9S8 is 134 and 9.1 times higher than that of pure hollow Co9S8 and CdS QDs under simulated solar light irradiation, respectively. Moreover, this is the first report describing construction of a hollow Co9S8 based Z‐scheme system for photocatalytic water splitting, which gives full play to the advantages of light‐harvesting and charges separation.

Abstract The double perovskite family, A 2 M I M III X 6 , is a promising route to overcome the lead toxicity issue confronting the current photovoltaic (PV) standout, CH 3 NH 3 PbI 3 . Given the generally large indirect band gap within most known double perovskites, band‐gap engineering provides an important approach for targeting outstanding PV performance within this family. Using Cs 2 AgBiBr 6 as host, band‐gap engineering through alloying of In III /Sb III has been demonstrated in the current work. Cs 2 Ag(Bi 1− x M x )Br 6 (M=In, Sb) accommodates up to 75 % In III with increased band gap, and up to 37.5 % Sb III with reduced band gap; that is, enabling ca. 0.41 eV band gap modulation through introduction of the two metals, with smallest value of 1.86 eV for Cs 2 Ag(Bi 0.625 Sb 0.375 )Br 6 . Band structure calculations indicate that opposite band gap shift directions associated with Sb/In substitution arise from different atomic configurations for these atoms. Associated photoluminescence and environmental stability of the three‐metal systems are also assessed.

Abstract Understanding the pathways of catalyst degradation during the oxygen evolution reaction is a cornerstone in the development of efficient and stable electrolyzers, since even for the most promising Ir based anodes the harsh reaction conditions are detrimental. The dissolution mechanism is complex and the correlation to the oxygen evolution reaction itself is still poorly understood. Here, by coupling a scanning flow cell with inductively coupled plasma and online electrochemical mass spectrometers, we monitor the oxygen evolution and degradation products of Ir and Ir oxides in situ. It is shown that at high anodic potentials several dissolution routes become possible, including formation of gaseous IrO 3 . On the basis of experimental data, possible pathways are proposed for the oxygen‐evolution‐triggered dissolution of Ir and the role of common intermediates for these reactions is discussed.

Stretchability and compressibility of supercapacitors is an essential element of modern electronics, such as flexible, wearable devices. Widely used polyvinyl alcohol-based electrolytes are neither very stretchable nor compressible, which fundamentally limits the realization of supercapacitors with high stretchability and compressibility. A new electrolyte that is intrinsically super-stretchable and compressible is presented. Vinyl hybrid silica nanoparticle cross-linkers were introduced into polyacrylamide hydrogel backbones to promote dynamic cross-linking of the polymer networks. These cross-linkers serve as stress buffers to dissipate energy when strain is applied, providing a solution to the intrinsically low stretchability and compressibility shortcomings of conventional supercapacitors. The newly developed supercapacitor and electrolyte can be stretched up to an unprecedented 1000 % strain with enhanced performance, and compressed to 50 % strain with good retention of the initial performance.

A curated library of circular dichroism spectra of 23 G-quadruplexes of known structure was built and analyzed. The goal of this study was to use this reference library to develop an algorithm to derive quantitative estimates of the secondary structure content of quadruplexes from their experimental CD spectra. Principal component analysis and singular value decomposition were used to characterize the reference spectral library. CD spectra were successfully fit to obtain estimates of the amounts of base steps in anti-anti, syn-anti or anti-syn conformations, in diagonal or lateral loops, or in other conformations. The results show that CD spectra of nucleic acids can be analyzed to obtain quantitative structural information about secondary structure content in an analogous way to methods used to analyze protein CD spectra.

The various applications of hydrogen isotopes (deuterium, D, and tritium, T) in the physical and life sciences demand a range of methods for their installation in an array of molecular architectures. In this Review, we describe recent advances in synthetic C-H functionalisation for hydrogen isotope exchange.

Abstract BiVO4 films with (040) facet grown vertically on fluorine doped SnO2 (FTO) glass substrates are prepared by a seed‐assisted hydrothermal method. A simple electrochemical treatment process drastically enhances the photocatalytic activity of BiVO4, exhibiting a remarkable photocurrent density of 2.5 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 G illumination, which is approximately 10‐fold higher than that of the pristine photoanode. Loading cobalt borate (CoBi) as cocatalyst, the photocurrent density of the BiVO4 photoanode can be further improved to 3.2 mA cm−2, delivering an applied bias photon‐to‐current efficiency (ABPE) of 1.1 %. Systematic studies reveal that crystal facet orientation also synergistically boosts both charge separation and transfer efficiencies, resulting in remarkably enhanced photocurrent densities. These findings provide a facile and effective approach for the development of efficient photoelectrodes for photoelectrochemical water splitting.

Organic-inorganic perovskites have made tremendous progress in recent years due to exceptional material properties such as high panchromatic absorption, charge carrier diffusion lengths, and a sharp optical band edge. The combination of high-quality semiconductor performance with low-cost deposition techniques seems to be a match made in heaven, creating great excitement far beyond academic ivory towers. This is particularly true for perovskite solar cells (PSCs) that have shown unprecedented gains in efficiency and stability over a time span of just five years. Now there are serious efforts for commercialization with the hope that PSCs can make a major impact in generating inexpensive, sustainable solar electricity. In this Review, we will focus on perovskite material properties as well as on devices from the atomic to the thin film level to highlight the remaining challenges and to anticipate the future developments of PSCs.

Abstract Mesoporous carbon nitrides (MCN) are fascinating materials with unique semiconducting and basic properties that are useful in many applications including photocatalysis and sensing. Most syntheses of MCN focus on creating theoretically predicted C3N4 stoichiometry with a band gap of 2.7 eV using a nano‐hard templating approach with triazine‐based precursors. However, the performance of the MCN in semiconducting applications is limited to the MCN framework with a small band gap, which would be linked with the addition of more N in the CN framework, but this remains a huge challenge. Here, we report a precursor with high nitrogen content, 3‐amino‐1,2,4‐triazole, that enables the formation of new and well‐ordered 3D MCN with C3N5 stoichiometry (MCN‐8), which has not been predicted so far, and a low‐band‐gap energy (2.2 eV). This novel class of material without addition of any dopants shows not only a superior photocatalytic water‐splitting performance with a total of 801 μmol of H2 under visible‐light irradiation for 3 h but also excellent sensing properties for toxic acids.

Single-atom catalysts (SACs) have exhibited high activities for the hydrogen evolution reaction (HER) electrocatalysis in acidic or alkaline media, when they are used with binders on cathodes. However, to date, no SACs have been reported for the HER electrocatalysis in neutral media. We demonstrate a potential-cycling method to synthesize a catalyst comprising single Pt atoms on CoP-based nanotube arrays supported by a Ni foam, termed PtSA-NT-NF. This binder-free catalyst is centimeter-scale and scalable. It is directly used as HER cathodes, whose performances at low and high current densities in phosphate buffer solutions (pH 7.2) are comparable to and better than, respectively, those of commercial Pt/C. The Pt mass activity of PtSA-NT-NF is 4 times of that of Pt/C, and its electrocatalytic stability is also better than that of Pt/C. This work provides a large-scale production strategy for binder-free Pt SAC electrodes for efficient HER in neutral media.

Porous organic materials are an emerging class of functional nanostructures with unprecedented properties. Dynamic covalent assembly of small organic building blocks under thermodynamic control is utilized for the intriguingly simple formation of complex molecular architectures in one-pot procedures. In this Review, we aim to analyze the basic design principles that govern the formation of either covalent organic frameworks as crystalline porous polymers or covalent organic cage compounds as shape-persistent molecular objects. Common synthetic procedures and characterization techniques will be discussed as well as more advanced strategies such as postsynthetic modification or self-sorting. When appropriate, comparisons are drawn between polymeric frameworks and discrete organic cages in terms of their underlying properties. Furthermore, we highlight the potential of these materials for applications ranging from gas storage to catalysis and organic electronics.

Abstract A one‐step ligand‐free method based on an adsorption–precipitation process was developed to fabricate iridium/cerium oxide (Ir/CeO2) nanocatalysts. Ir species demonstrated a strong metal–support interaction (SMSI) with the CeO2 substrate. The chemical state of Ir could be finely tuned by altering the loading of the metal. In the carbon dioxide (CO2) hydrogenation reaction it was shown that the chemical state of Ir species—induced by a SMSI—has a major impact on the reaction selectivity. Direct evidence is provided indicating that a single‐site catalyst is not a prerequisite for inhibition of methanation and sole production of carbon monoxide (CO) in CO2 hydrogenation. Instead, modulation of the chemical state of metal species by a strong metal–support interaction is more important for regulation of the observed selectivity (metallic Ir particles select for methane while partially oxidized Ir species select for CO production). The study provides insight into heterogeneous catalysts at nano, sub‐nano, and atomic scales.

Abstract Photothermal therapy (PTT) has shown significant potential for cancer therapy. However, developing nanomaterials (NMs)‐based photothermal agents (PTAs) with satisfactory photothermal conversion efficacy (PTCE) and biocompatibility remains a key challenge. Herein, a new generation of PTAs based on two‐dimensional (2D) antimonene quantum dots (AMQDs) was developed by a novel liquid exfoliation method. Surface modification of AMQDs with polyethylene glycol (PEG) significantly enhanced both biocompatibility and stability in physiological medium. The PEG‐coated AMQDs showed a PTCE of 45.5 %, which is higher than many other NMs‐based PTAs such as graphene, Au, MoS 2 , and black phosphorus (BP). The AMQDs‐based PTAs also exhibited a unique feature of NIR‐induced rapid degradability. Through both in vitro and in vivo studies, the PEG‐coated AMQDs demonstrated notable NIR‐induced tumor ablation ability. This work is expected to expand the utility of 2D antimonene (AM) to biomedical applications through the development of an entirely novel PTA platform.

Abstract The electrocatalyzed oxygen reduction and evolution reactions (ORR and OER, respectively) are the core components of many energy conversion systems, including water splitting, fuel cells, and metal–air batteries. Rational design of highly efficient non‐noble materials as bifunctional ORR/OER electrocatalysts is of great importance for large‐scale practical applications. A new strongly coupled hybrid material is presented, which comprises CoOx nanoparticles rich in oxygen vacancies grown on B,N‐decorated graphene (CoOx NPs/BNG) and operates as an efficient bifunctional OER/ORR electrocatalyst. Advanced spectroscopic techniques were used to confirm formation of abundant oxygen vacancies and strong Co−N−C bridging bonds within the CoOx NPs/BNG hybrid. Surprisingly, the CoOx NPs/BNG hybrid electrocatalyst is highly efficient for the OER with a low overpotential and Tafel slope, and is active in the ORR with a positive half‐wave potential and high limiting current density in alkaline medium.

Phosphorus is a nonmetal with several allotropes, from the highly reactive white phosphorus to the thermodynamically stable black phosphorus (BP) with a puckered orthorhombic layered structure. The bulk form of BP was first synthesized in 1914, but received little attention until it was rediscovered in 2014 as a member of the new wave of 2D layered nanomaterials. BP can be exfoliated to a single sheet that acts as a semiconductor with a tunable direct band gap, a high carrier mobility at room temperature, and an in-plane anisotropy. The development of BP applications is hampered by surface degradation, thus efforts to achieve effective BP passivation are ongoing, such as its integration in van der Waals heterostructures. BP has been tested as a novel nanomaterial in batteries, transistors, sensors, and photonics. This Review begins with the origin of the BP story, following the path from a bulk material to modern few/single layers. The physical and chemical properties are summarized, and the state-of-the-art of BP applications highlighted.

Abstract A novel OER electrocatalyst, namely oxygen‐incorporated amorphous cobalt sulfide porous nanocubes (A‐CoS4.6O0.6 PNCs), show advantages over the benchmark RuO2 catalyst in alkaline/neutral medium. Experiments combining with calculation demonstrate that the desirable O* adsorption energy, associated with the distorted CoS4.6O0.6 octahedron structure and the oxygen doping, contribute synergistically to the outstanding electrocatalytic activity.

Abstract The highly efficient electrochemical hydrogen evolution reaction (HER) provides a promising pathway to resolve energy and environment problems. An electrocatalyst was designed with single Mo atoms (Mo‐SAs) supported on N‐doped carbon having outstanding HER performance. The structure of the catalyst was probed by aberration‐corrected scanning transmission electron microscopy (AC‐STEM) and X‐ray absorption fine structure (XAFS) spectroscopy, indicating the formation of Mo‐SAs anchored with one nitrogen atom and two carbon atoms (Mo1N1C2). Importantly, the Mo1N1C2 catalyst displayed much more excellent activity compared with Mo2C and MoN, and better stability than commercial Pt/C. Density functional theory (DFT) calculation revealed that the unique structure of Mo1N1C2 moiety played a crucial effect to improve the HER performance. This work opens up new opportunities for the preparation and application of highly active and stable Mo‐based HER catalysts.

Colloidal photonic crystals (PCs) have been well developed because they are easy to prepare, cost-effective, and versatile with regards to modification and functionalization. Patterned colloidal PCs contribute a novel approach to constructing high-performance PC devices with unique structures and specific functions. In this review, an overview of the strategies for fabricating patterned colloidal PCs, including patterned substrate-induced assembly, inkjet printing, and selective immobilization and modification, is presented. The advantages of patterned PC devices are also discussed in detail, for example, improved detection sensitivity and response speed of the sensors, control over the flow direction and wicking rate of microfluidic channels, recognition of cross-reactive molecules through an array-patterned microchip, fabrication of display devices with tunable patterns, well-arranged RGB units, and wide viewing-angles, and the ability to construct anti-counterfeiting devices with different security strategies. Finally, the perspective of future developments and challenges is…

Abstract 0D/2D heterojunctions, especially quantum dots (QDs)/nanosheets (NSs) have attracted significant attention for use of photoexcited electrons/holes due to their high charge mobility. Herein, unprecedent heterojunctions of vanadate (AgVO3, BiVO4, InVO4 and CuV2O6) QDs/graphitic carbon nitride (g‐C3N4) NSs exhibiting multiple unique advances beyond traditional 0D/2D composites have been developed. The photoactive contribution, up‐conversion absorption, and nitrogen coordinating sites of g‐C3N4 NSs, highly dispersed vanadate nanocrystals, as well as the strong coupling and band alignment between them lead to superior visible‐light‐driven photoelectrochemical (PEC) and photocatalytic performance, competing with the best reported photocatalysts. This work is expected to provide a new concept to construct multifunctional 0D/2D nanocomposites for a large variety of opto‐electronic applications, not limited in photocatalysis.

Despite its widespread use in signal collection, flexible sensors have been rarely used in human-machine interactions owing to its indistinguishable signal, poor reliability, and poor stability when inflicted with unavoidable scratches and/or mechanical cuts. A highly sensitive and self-healing sensor enabled by multiple hydrogen bonding network and nanostructured conductive network is demonstrated. The nanostructured supramolecular sensor displays extremely fast (ca. 15 s) and repeatable self-healing ability with high healing efficiency (93 % after the third healing process). It can precisely detect tiny human motions, demonstrating highly distinguishable and reliable signals even after cutting-healing and bending over 20 000 cycles. Furthermore, a human-machine interaction system is integrated to develop a facial expression control system and an electronic larynx, aiming to control the robot to assist the patient's daily life and help the mute to realize real-time speaking.

Biothiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) play crucial roles in maintaining redox homeostasis in biological systems. This Minireview summarizes the most significant current challenges in the field of thiol-reactive probes for biomedical research and diagnostics, emphasizing the needs and opportunities that have been under-investigated by chemists in the selective probe and sensor field. Progress on multiple binding site probes to distinguish Cys, Hcy, and GSH is highlighted as a creative new direction in the field that can enable simultaneous, accurate ratiometric monitoring. New probe design strategies and researcher priorities can better help address current challenges, including the monitoring of disease states such as autism and chronic diseases involving oxidative stress that are characterized by divergent levels of GSH, Cys, and Hcy.

Exosomes constitute an emerging biomarker for cancer diagnosis because they carry multiple proteins that reflect the origins of parent cells. Assessing exosome surface proteins provides a powerful means of identifying a combination of biomarkers for cancer diagnosis. We report a sensor platform that profiles exosome surface proteins in minutes by the naked eye. The sensor consists of a gold nanoparticle (AuNP) complexed with a panel of aptamers. The complexation of aptamers with AuNPs protects the nanoparticles from aggregating in a high-salt solution. In the presence of exosomes, the non-specific and weaker binding between aptamers and the AuNP is broken, and the specific and stronger binding between exosome surface protein and the aptamer displaces aptamers from the AuNP surface and results in AuNP aggregation. This aggregation results in a color change and generates patterns for the identification of multiple proteins on the exosome surface.

Abstract Herein, the assembly of CsPbBr 3 QD/AlO x inorganic nanocomposites, by using atomic layer deposition (ALD) for the growth of the amorphous alumina matrix (AlO x ), is described as a novel protection scheme for such QDs. The nucleation and growth of AlO x on the QD surface was thoroughly investigated by miscellaneous techniques, which highlighted the importance of the interaction between the ALD precursors and the QD surface to uniformly coat the QDs while preserving the optoelectronic properties. These nanocomposites show exceptional stability towards exposure to air (for at least 45 days), irradiation under simulated solar spectrum conditions (for at least 8 h), and heat (up to 200 °C in air), and finally upon immersion in water. This method was extended to the assembly of CsPbBr x I 3− x QD/AlO x and CsPbI 3 QD/AlO x nanocomposites, which were more stable than the pristine QD films.

Abstract Various advanced catalysts based on sulfur‐doped Fe/N/C materials have recently been designed for the oxygen reduction reaction (ORR); however, the enhanced activity is still controversial and usually attributed to differences in the surface area, improved conductivity, or uncertain synergistic effects. Herein, a sulfur‐doped Fe/N/C catalyst (denoted as Fe/SNC) was obtained by a template‐sacrificing method. The incorporated sulfur gives a thiophene‐like structure (C−S−C), reduces the electron localization around the Fe centers, improves the interaction with oxygenated species, and therefore facilitates the complete 4 e− ORR in acidic solution. Owing to these synergistic effects, the Fe/SNC catalyst exhibits much better ORR activity than the sulfur‐free variant (Fe/NC) in 0.5 m H2SO4.

Abstract The transformation of CO 2 into fuels and chemicals by photocatalysis is a promising strategy to provide a long‐term solution to mitigating global warming and energy‐supply problems. Achievements in photocatalysis during the last decade have sparked increased interest in using sunlight to reduce CO 2 . Traditional semiconductors used in photocatalysis (e.g. TiO 2 ) are not suitable for use in natural sunlight and their performance is not sufficient even under UV irradiation. Some two‐dimensional (2D) materials have recently been designed for the catalytic reduction of CO 2 . These materials still require significant modification, which is a challenge when designing a photocatalytic process. An overarching aim of this Review is to summarize the literature on the photocatalytic conversion of CO 2 by various 2D materials in the liquid phase, with special attention given to the development of novel 2D photocatalyst materials to provide a basis for improved materials.

Abstract An active and stable photocatalyst to directly split water is desirable for solar‐energy conversion. However, it is difficult to accomplish overall water splitting without sacrificial electron donors. Herein, we demonstrate a strategy via constructing a single site to simultaneously promote charge separation and catalytic activity for robust overall water splitting. A single Co 1 ‐P 4 site confined on g‐C 3 N 4 nanosheets was prepared by a facile phosphidation method, and identified by electron microscopy and X‐ray absorption spectroscopy. This coordinatively unsaturated Co site can effectively suppress charge recombination and prolong carrier lifetime by about 20 times relative to pristine g‐C 3 N 4 , and boost water molecular adsorption and activation for oxygen evolution. This single‐site photocatalyst exhibits steady and high water splitting activity with H 2 evolution rate up to 410.3 μmol h −1 g −1 , and quantum efficiency as high as 2.2 % at 500 nm.

Abstract Vacancy‐rich layered materials with good electron‐transfer property are of great interest. Herein, a full‐spectrum responsive vacancy‐rich monolayer BiO 2− x has been synthesized. The increased density of states at the conduction band (CB) minimum in the monolayer BiO 2− x is responsible for the enhanced photon response and photo‐absorption, which were confirmed by UV/Vis‐NIR diffuse reflectance spectra (DRS) and photocurrent measurements. Compared to bulk BiO 2− x , monolayer BiO 2− x has exhibited enhanced photocatalytic performance for rhodamine B and phenol removal under UV, visible, and near‐infrared light (NIR) irradiation, which can be attributed to the vacancy V Bi‐O ′′′ as confirmed by the positron annihilation spectra. The presence of V Bi‐O ′′′ defects in monolayer BiO 2− x promoted the separation of electrons and holes. This finding provides an atomic level understanding for developing highly efficient UV, visible, and NIR light responsive photocatalysts.

Abstract Metal–organic framework (MOF) nanosheets could serve as ideal building blocks of molecular sieve membranes owing to their structural diversity and minimized mass‐transfer barrier. To date, discovery of appropriate MOF nanosheets and facile fabrication of high performance MOF nanosheet‐based membranes remain as great challenges. A modified soft‐physical exfoliation method was used to disintegrate a lamellar amphiprotic MOF into nanosheets with a high aspect ratio. Consequently sub‐10 nm‐thick ultrathin membranes were successfully prepared, and these demonstrated a remarkable H2/CO2 separation performance, with a separation factor of up to 166 and H2 permeance of up to 8×10−7 mol m−2 s−1 Pa−1 at elevated testing temperatures owing to a well‐defined size‐exclusion effect. This nanosheet‐based membrane holds great promise as the next generation of ultrapermeable gas separation membrane.

Abstract Aqueous rechargeable batteries are promising solutions for large‐scale energy storage. Such batteries have the merit of low cost, innate safety, and environmental friendliness. To date, most known aqueous ion batteries employ metal cation charge carriers. Here, we report the first “rocking‐chair” NH4‐ion battery of the full‐cell configuration by employing an ammonium Prussian white analogue, (NH4)1.47Ni[Fe(CN)6]0.88, as the cathode, an organic solid, 3,4,9,10‐perylenetetracarboxylic diimide (PTCDI), as the anode, and 1.0 m aqueous (NH4)2SO4 as the electrolyte. This novel aqueous ammonium‐ion battery demonstrates encouraging electrochemical performance: an average operation voltage of ca. 1.0 V, an attractive energy density of ca. 43 Wh kg−1 based on both electrodes’ active mass, and excellent cycle life over 1000 cycles with 67 % capacity retention. Importantly, the topochemistry results of NH4+ in these electrodes point to a new paradigm of NH4+‐based energy storage.

Transition-metal dichalcogenides (TMDs) have attracted considerable attention in recent years because of their unique properties and promising applications in electrochemical energy storage and conversion. However, the limited number of active sites as well as blocked ion and mass transport severely impair their electrochemical performance. The construction of three-dimensional (3D) architectures from TMD nanomaterials has been proven to be an effective strategy to solve the aforementioned problems as a result of their large specific surface areas and short ion and mass transport distances. This Review summarizes the commonly used routes to build 3D TMD architectures and highlights their applications in electrochemical energy storage and conversion, including batteries, supercapacitors, and electrocatalytic hydrogen evolution. The challenges and outlook in this research area are also discussed.

This Review gives a comprehensive overview of the most topical weakly coordinating anions (WCAs) and contains information on WCA design, stability, and applications. As an update to the 2004 review, developments in common classes of WCA are included. Methods for the incorporation of WCAs into a given system are discussed and advice given on how to best choose a method for the introduction of a particular WCA. A series of starting materials for a large number of WCA precursors and references are tabulated as a useful resource when looking for procedures to prepare WCAs. Furthermore, a collection of scales that allow the performance of a WCA, or its underlying Lewis acid, to be judged is collated with some advice on how to use them. The examples chosen to illustrate WCA developments are taken from a broad selection of topics where WCAs play a role. In addition a section focusing on transition metal and catalysis applications as well as supporting electrolytes is also included.

Abstract Electrochemical conversion of CO 2 into energy‐dense liquids, such as formic acid, is desirable as a hydrogen carrier and a chemical feedstock. SnO x is one of the few catalysts that reduce CO 2 into formic acid with high selectivity but at high overpotential and low current density. We show that an electrochemically reduced SnO 2 porous nanowire catalyst (Sn‐pNWs) with a high density of grain boundaries (GBs) exhibits an energy conversion efficiency of CO 2 ‐into‐HCOOH higher than analogous catalysts. HCOOH formation begins at lower overpotential (350 mV) and reaches a steady Faradaic efficiency of ca. 80 % at only −0.8 V vs. RHE. A comparison with commercial SnO 2 nanoparticles confirms that the improved CO 2 reduction performance of Sn‐pNWs is due to the density of GBs within the porous structure, which introduce new catalytically active sites. Produced with a scalable plasma synthesis technology, the catalysts have potential for application in the CO 2 conversion industry.

Three-dimensional (3D) networks of graphitic carbon are promising materials for energy storage and conversion devices because of their high electrical conductivity, which is promoted by the good interconnection between the carbon particles. However, it is still difficult to directly synthesize such carbon networks. Herein, we report the novel synthesis of 3D graphitic carbon networks through the pyrolysis of nanosized ZIF-67 crystals. Interestingly, the unusual effect of downsizing the ZIF-67 crystals and the incorporation of catalytic Co nanoparticles was the spontaneous formation of graphitic networks. The obtained graphitic carbon networks show excellent electrochemical performance for the insertion and extraction of potassium ions.

Abstract The delamination of layered crystals that produces single or few‐layered nanosheets while enabling exotic physical and chemical properties, particularly for semiconductor functions in optoelectronic applications, remains a challenge. Here, we report a facile and green approach to prepare few‐layered polymeric carbon nitride (PCN) semiconductors by a one‐step carbon/nitrogen steam reforming reaction. Bulky PCN, obtained from typical precursors including urea, melamine, dicyandiamide, and thiourea, are exfoliated into few‐layered nanosheets, while engineering its surface carbon vacancies. The unique sheet structures with strengthened surface properties endow PCNs with more active sites, and an increased charge separation efficiency with a prolonged charge lifetime, drastically promoting their photoredox performance. After an assay of a H 2 evolution reaction, an apparent quantum yield of 11.3 % at 405 nm was recorded for the PCN nanosheets, which is much higher than those of PCN nanosheets. This delamination method is expandable to other carbon‐based 2D materials for advanced…

Abstract We successfully prepared QDs incorporated into a silica/alumina monolith (QDs‐SAM) by a simple sol–gel reaction of an Al–Si single precursor with CsPbBr3 QDs blended in toluene solution, without adding water and catalyst. The resultant transparent monolith exhibits high photoluminescence quantum yields (PLQY) up to 90 %, and good photostability under strong illumination of blue light for 300 h. We show that the preliminary ligand exchange of didodecyl dimethyl ammonium bromide (DDAB) was very important to protect CsPbBr3 QDs from surface damages during the sol–gel reaction, which not only allowed us to maintain the original optical properties of CsPbBr3 QDs but also prevented the aggregation of QDs and made the monolith transparent. The CsPbBr3 QDs‐SAM in powder form was easily mixed into the resins and applied as color‐converting layer with curing on blue light‐emitting diodes (LED). The material showed a high luminous efficacy of 80 lm W−1 and a narrow emission with a full width at half maximum (FWHM) of 25 nm.

Abstract Biocatalytic transformation has received increasing attention in the green synthesis of chemicals because of the diversity of enzymes, their high catalytic activities and specificities, and mild reaction conditions. The idea of solar energy utilization in chemical synthesis through the combination of photocatalysis and biocatalysis provides an opportunity to make the “green” process greener. Oxidoreductases catalyze redox transformation of substrates by exchanging electrons at the enzyme′s active site, often with the aid of electron mediator(s) as a counterpart. Recent progress indicates that photoinduced electron transfer using organic (or inorganic) photosensitizers can activate a wide spectrum of redox enzymes to catalyze fuel‐forming reactions (e.g., H2 evolution, CO2 reduction) and synthetically useful reductions (e.g., asymmetric reduction, oxygenation, hydroxylation, epoxidation, Baeyer–Villiger oxidation). This Review provides an overview of recent advances in light‐driven activation of redox enzymes through direct or indirect transfer of photoinduced electrons.

Abstract In a comparative study of the electrocatalytic CO 2 reduction, cobalt meso‐tetraphenylporphyrin (CoTPP) is used as a model molecular catalyst under both homogeneous and heterogeneous conditions. In the former case, employing N,N‐dimethylformamide as solvent, CoTPP performs poorly as an electrocatalyst giving low product selectivity in a slow reaction at a high overpotential. However, upon straightforward immobilization of CoTPP onto carbon nanotubes, a remarkable enhancement of the electrocatalytic abilities is seen with CO 2 becoming selectively reduced to CO (>90 %) at a low overpotential in aqueous medium. This effect is ascribed to the particular environment created by the aqueous medium at the catalytic site of the immobilized catalyst that facilitates the adsorption and further reaction of CO 2 . This work highlights the significance of assessing an immobilized molecular catalyst from more than homogeneous measurements alone.

Biological processes are naturally regulated with high spatial and temporal control, as is perhaps most evident in metazoan embryogenesis. Chemical tools have been extensively utilized in cell and developmental biology to investigate cellular processes, and conditional control methods have expanded applications of these technologies toward resolving complex biological questions. Light represents an excellent external trigger since it can be controlled with very high spatial and temporal precision. To this end, several optically regulated tools have been developed and applied to living systems. In this review we discuss recent developments of optochemical tools, including small molecules, peptides, proteins, and nucleic acids that can be irreversibly or reversibly controlled through light irradiation, with a focus on applications in cells and animals.

Abstract Complex metal–organic frameworks used as precursors allow design and construction of various nanostructured functional materials which might not be accessible by other methods. Here, we develop a sequential chemical etching and sulfurization strategy to prepare well‐defined double‐shelled zinc–cobalt sulfide (Zn‐Co‐S) rhombic dodecahedral cages (RDCs). Yolk‐shelled zinc/cobalt‐based zeolitic imidazolate framework (Zn/Co‐ZIF) RDCs are first synthesized by a controlled chemical etching process, followed by a hydrothermal sulfurization reaction to prepare double‐shelled Zn‐Co‐S RDCs. Moreover, the strategy reported in this work enables easy control of the Zn/Co molar ratio in the obtained double‐shelled Zn‐Co‐S RDCs. Owing to the structural and compositional benefits, the obtained double‐shelled Zn‐Co‐S RDCs exhibit enhanced performance with high specific capacitance (1266 F g−1 at 1 A g−1), good rate capability and long‐term cycling stability (91 % retention over 10,000 cycles) as a battery‐type electrode material for hybrid supercapacitors.

Essentially, the term aerogel describes a special geometric structure of matter. It is neither limited to any material nor to any synthesis procedure. Hence, the possible variety of materials and therefore the multitude of their applications are almost unbounded. In fact, the same applies for nanoparticles. These are also just defined by their geometrical properties. In the past few decades nano-sized materials have been intensively studied and possible applications appeared in nearly all areas of natural sciences. To date a large variety of metal, semiconductor, oxide, and other nanoparticles are available from colloidal synthesis. However, for many applications of these materials an assembly into macroscopic structures is needed. Here we present a comprehensive picture of the developments that enabled the fusion of the colloidal nanoparticle and the aerogel world. This became possible by the controlled destabilization of pre-formed nanoparticles, which leads to their assembly into three-dimensional macroscopic networks. This revolutionary approach makes it possible to use…

Fabrication of hybrid MOF-on-MOF heteroarchitectures can create novel and multifunctional platforms to achieve desired properties. However, only MOFs with similar crystallographic parameters can be hybridized by the classical epitaxial growth method (EGM), which largely suppressed its applications. A general strategy, called internal extended growth method (IEGM), is demonstrated for the feasible assembly of MOFs with distinct crystallographic parameters in an MOF matrix. Various MOFs with diverse functions could be introduced in a modular MOF matrix to form 3D core-satellite pluralistic hybrid system. The number of different MOF crystals interspersed could be varied on demand. More importantly, the different MOF crystals distributed in individual domains could be used to further incorporate functional units or enhance target functions.

Bright fluorophores in the near-infrared and shortwave infrared (SWIR) regions of the electromagnetic spectrum are essential for optical imaging in vivo. In this work, we utilized a 7-dimethylamino flavylium heterocycle to construct a panel of novel red-shifted polymethine dyes, with emission wavelengths from 680 to 1045 nm. Photophysical characterization revealed that the 1- and 3-methine dyes display enhanced photostability and the 5- and 7-methine dyes exhibit exceptional brightness for their respective spectral regions. A micelle formulation of the 7-methine facilitated SWIR imaging in mice. This report presents the first polymethine dye designed and synthesized for SWIR in vivo imaging.

We report a facile approach to prepare an artificial enzyme system for tandem catalysis. NiPd hollow nanoparticles and glucose oxidase (GOx) were simultaneously immobilized on the zeolitic imidazolate framework 8 (ZIF-8) via a co-precipitation method. The as-prepared GOx@ZIF-8(NiPd) nanoflower not only exhibited the peroxidase-like activity of NiPd hollow nanoparticles but also maintained the enzymatic activity of GOx. A colorimetric sensor for rapid detection of glucose was realized through the GOx@ZIF-8(NiPd) based multi-enzyme system. Moreover, the GOx@ZIF-8(NiPd) modified electrode showed good bioactivity of GOx and high electrocatalytic activity for the oxygen reduction reaction (ORR), which could also be used for electrochemical detection of glucose.

Abstract Heteroatom doping is an effective way to adjust the fluorescent properties of carbon quantum dots. However, selenium‐doped carbon dots have rarely been reported, even though selenium has unique chemical properties such as redox‐responsive properties owing to its special electronegativity. Herein, a facile and high‐output strategy to fabricate selenium‐doped carbon quantum dots (Se‐CQDs) with green fluorescence (quantum yield 7.6 %) is developed through the hydrothermal treatment of selenocystine under mild conditions. Selenium heteroatoms endow the Se‐CQDs with redox‐dependent reversible fluorescence. Furthermore, free radicals such as . OH can be effectively scavenged by the Se‐CQDs. Once Se‐CQDs are internalized into cells, harmful high levels of reactive oxygen species (ROS) in the cells are decreased. This property makes the Se‐CQDs capable of protecting biosystems from oxidative stress.

Abstract Proton adsorption on metallic catalysts is a prerequisite for efficient hydrogen evolution reaction (HER). However, tuning proton adsorption without perturbing metallicity remains a challenge. A Schottky catalyst based on metal–semiconductor junction principles is presented. With metallic MoB, the introduction of n‐type semiconductive g‐C3N4 induces a vigorous charge transfer across the MoB/g‐C3N4 Schottky junction, and increases the local electron density in MoB surface, confirmed by multiple spectroscopic techniques. This Schottky catalyst exhibits a superior HER activity with a low Tafel slope of 46 mV dec−1 and a high exchange current density of 17 μA cm−2, which is far better than that of pristine MoB. First‐principle calculations reveal that the Schottky contact dramatically lowers the kinetic barriers of both proton adsorption and reduction coordinates, therefore benefiting surface hydrogen generation.

CRISPR/Cas9 system is a powerful toolbox for gene editing. However, the low delivery efficiency is still a big hurdle impeding its applications. Herein, we report a strategy to deliver Cas9-sgPlk-1 plasmids (CP) by a multifunctional vehicle for tumor therapy. We condensed CPs on TAT peptide-modified Au nanoparticles (AuNPs/CP, ACP) via electrostatic interactions, and coated lipids (DOTAP, DOPE, cholesterol, PEG2000-DSPE) on the ACP to form lipid-encapsulated, AuNPs-condensed CP (LACP). LACP can enter tumor cells and release CP into the cytosol by laser-triggered thermo-effects of the AuNPs; the CP can enter nuclei by TAT guidance, enabling effective knock-outs of target gene (Plk-1) of tumor (melanoma) and inhibition of the tumor both in vitro and in vivo. This AuNPs-condensed, lipid-encapsulated, and laser-controlled delivery system provides a versatile method for high efficiency CRISPR/Cas9 delivery and targeted gene editing for treatment of a wide spectrum of diseases.

Abstract Oxide‐derived (OD) Cu catalysts have high selectivity towards the formation of multi‐carbon products (C2/C3) for aqueous electrochemical CO2 reduction (CO2R). It has been proposed that a large fraction of the initial oxide can be surprisingly resistant to reduction, and these residual oxides play a crucial catalytic role. The stability of residual oxides was investigated by synthesizing 18O‐enriched OD Cu catalysts and testing them for CO2R. These catalysts maintain a high selectivity towards C2/C3 products (ca. 60 %) for up to 5 h in 0.1 m KHCO3 at −1.0 V vs. RHE. However, secondary‐ion mass spectrometry measurements show that only a small fraction (<1 %) of the original 18O content remains, showing that residual oxides are not present in significant amounts during CO2R. Furthermore, we show that OD Cu can reoxidize rapidly, which could compromise the accuracy of ex situ methods for determining the true oxygen content.

Abstract Three‐dimensional covalent organic frameworks (3D COFs) are promising crystalline materials with well‐defined structures, high porosity, and low density; however, the limited choice of building blocks and synthetic difficulties have hampered their development. Herein, we used a flexible and aliphatic macrocycle, namely γ‐cyclodextrin (γ‐CD), as the soft struts for the construction of a polymeric and periodic 3D extended network, with the units joined via tetrakis(spiroborate) tetrahedra with various counterions. The inclusion of pliable moieties in the robust open framework endows these CD‐COFs with dynamic features, leading to a prominent Li ion conductivity of up to 2.7 mS cm −1 at 30 °C and excellent long‐term Li ion stripping/plating stability. Exchanging the counterions within the pores can effectively modulate the interactions between the CD‐COF and CO 2 molecules.

Owing to their water-rich structures, which are similar to those of biological tissues, hydrogels have long been regarded as promising scaffolds for artificial tissues and organs. However, in terms of the structural anisotropy, most synthetic hydrogels are substantially different from biological systems. Synthetic hydrogels are usually composed of randomly oriented three-dimensional polymer networks whereas biological systems adopt anisotropic structures with hierarchically integrated building units. Such anisotropic structures often play essential roles in biological systems to exhibit particular functions. In this context, anisotropic hydrogels provide an entry point for exploring biomimetic applications of hydrogels. Reflecting these aspects, an increasing number of studies on anisotropic hydrogels have been reported recently. This Minireview highlights the use and perspectives of these anisotropic hydrogels, particularly focusing on their preparation, structures, and applications.

Abstract CO 2 electroreduction is a promising technique for satisfying both renewable energy storage and a negative carbon cycle. However, it remains a challenge to convert CO 2 into C2 products with high efficiency and selectivity. Herein, we report a nitrogen‐doped ordered cylindrical mesoporous carbon as a robust metal‐free catalyst for CO 2 electroreduction, enabling the efficient production of ethanol with nearly 100 % selectivity and high faradaic efficiency of 77 % at −0.56 V versus the reversible hydrogen electrode. Experiments and density functional theory calculations demonstrate that the synergetic effect of the nitrogen heteroatoms and the cylindrical channel configurations facilitate the dimerization of key CO* intermediates and the subsequent proton–electron transfers, resulting in superior electrocatalytic performance for synthesizing ethanol from CO 2 .

Abstract Tuning the surface strain of heterogeneous catalysts represents a powerful strategy to engineer their catalytic properties by altering the electronic structures. However, a clear and systematic understanding of strain effect in electrochemical reduction of carbon dioxide is still lacking, which restricts the use of surface strain as a tool to optimize the performance of electrocatalysts. Herein, we demonstrate the strain effect in electrochemical reduction of CO 2 by using Pd octahedra and icosahedra with similar sizes as a well‐defined platform. The Pd icosahedra/C catalyst shows a maximum Faradaic efficiency for CO production of 91.1 % at −0.8 V versus reversible hydrogen electrode (vs. RHE), 1.7‐fold higher than the maximum Faradaic efficiency of Pd octahedra/C catalyst at −0.7 V (vs. RHE). The combination of molecular dynamic simulations and density functional theory calculations reveals that the tensile strain on the surface of icosahedra boosts the catalytic activity by shifting up the d ‐band center and thus strengthening the adsorption of key intermediate COOH*.…