The 100 most-cited articles in Angewandte Chemie International Edition, 2018

Visible-light photocatalysis has evolved over the last decade into a widely used method in organic synthesis. Photocatalytic variants have been reported for many important transformations, such as cross-coupling reactions, α-amino functionalizations, cycloadditions, ATRA reactions, or fluorinations. To help chemists select photocatalytic methods for their synthesis, we compare in this Review classical and photocatalytic procedures for selected classes of reactions and highlight their advantages and limitations. In many cases, the photocatalytic reactions proceed under milder reaction conditions, typically at room temperature, and stoichiometric reagents are replaced by simple oxidants or reductants, such as air, oxygen, or amines. Does visible-light photocatalysis make a difference in organic synthesis? The prospect of shuttling electrons back and forth to substrates and intermediates or to selectively transfer energy through a visible-light-absorbing photocatalyst holds the promise to improve current procedures in radical chemistry and to open up new avenues by accessing reactive…

Abstract Tailored to the specific tumour microenvironment, which involves acidity and the overproduction of hydrogen peroxide, advanced nanotechnology has been introduced to generate the hydroxyl radical (.OH) primarily for tumour chemodynamic therapy (CDT) through the Fenton and Fenton‐like reactions. Numerous studies have investigated the enhancement of CDT efficiency, primarily the increase in the amount of .OH generated. Notably, various strategies based on the Fenton reaction have been employed to enhance .OH generation, including nanomaterials selection, modulation of the reaction environment, and external energy fields stimulation, which are discussed systematically in this Minireview. Furthermore, the potential challenges and the methods used to facilitate CDT effectiveness are also presented to support this cutting‐edge research area.

In recent years the littering of plastics and the problems related to their persistence in the environment have become a major focus in both research and the news. Biodegradable polymers like poly(lactic acid) are seen as a suitable alternative to commodity plastics. However, poly(lactic acid) is basically non-degradable in seawater. Similarly, the degradation rate of other biodegradable polymers also crucially depends on the environments they end up in, such as soil or marine water, or when used in biomedical devices. In this Minireview, we show that biodegradation tests carried out in artificial environments lack transferability to real conditions and, therefore, highlight the necessity of environmentally authentic and relevant field-testing conditions. In addition, we focus on ecotoxicological implications of biodegradable polymers. We also consider the social aspects and ask how biodegradable polymers influence consumer behavior and municipal waste management. Taken together, this study is intended as a contribution towards evaluating the potential of biodegradable polymers as…

The direct synthetic organic use of electricity is currently experiencing a renaissance. More synthetically oriented laboratories working in this area are exploiting both novel and more traditional concepts, paving the way to broader applications of this niche technology. As only electrons serve as reagents, the generation of reagent waste is efficiently avoided. Moreover, stoichiometric reagents can be regenerated and allow a transformation to be conducted in an electrocatalytic fashion. However, the application of electroorganic transformations is more than minimizing the waste footprint, it rather gives rise to inherently safe processes, reduces the number of steps of many syntheses, allows for milder reaction conditions, provides alternative means to access desired structural entities, and creates intellectual property (IP) space. When the electricity originates from renewable resources, this surplus might be directly employed as a terminal oxidizing or reducing agent, providing an ultra-sustainable and therefore highly attractive technique. This Review surveys recent…

Abstract Chemodynamic therapy (CDT) utilizes iron‐initiated Fenton chemistry to destroy tumor cells by converting endogenous H 2 O 2 into the highly toxic hydroxyl radical ( . OH). There is a paucity of Fenton‐like metal‐based CDT agents. Intracellular glutathione (GSH) with . OH scavenging ability greatly reduces CDT efficacy. A self‐reinforcing CDT nanoagent based on MnO 2 is reported that has both Fenton‐like Mn 2+ delivery and GSH depletion properties. In the presence of HCO 3 − , which is abundant in the physiological medium, Mn 2+ exerts Fenton‐like activity to generate . OH from H 2 O 2 . Upon uptake of MnO 2 ‐coated mesoporous silica nanoparticles (MS@MnO 2 NPs) by cancer cells, the MnO 2 shell undergoes a redox reaction with GSH to form glutathione disulfide and Mn 2+ , resulting in GSH depletion‐enhanced CDT. This, together with the GSH‐activated MRI contrast effect and dissociation of MnO 2 , allows MS@MnO 2 NPs to achieve MRI‐monitored chemo–chemodynamic combination therapy.

Abstract MXenes, 2D compounds generated from layered bulk materials, have attracted significant attention in energy‐related fields. However, most syntheses involve HF, which is highly corrosive and harmful to lithium‐ion battery and supercapacitor performance. Here an alkali‐assisted hydrothermal method is used to prepare a MXene Ti 3 C 2 T x (T=OH, O). This route is inspired from a Bayer process used in bauxite refining. The process is free of fluorine and yields multilayer Ti 3 C 2 T x with ca. 92 wt % in purity (using 27.5 m NaOH, 270 °C). Without the F terminations, the resulting Ti 3 C 2 T x film electrode (ca. 52 μm in thickness, ca. 1.63 g cm −3 in density) is 314 F g −1 via gravimetric capacitance at 2 mV s −1 in 1 m H 2 SO 4 . This surpasses (by ca. 214 %) that of the multilayer Ti 3 C 2 T x prepared via HF treatments. This fluorine‐free method also provides an alkali‐etching strategy for exploring new MXenes for which the interlayer amphoteric/acidic atoms from the pristine MAX phase must be removed.

Despite its clinical promise, photodynamic therapy (PDT) suffers from a key drawback associated with its oxygen-dependent nature, which limits its effective use against hypoxic tumors. Moreover, both PDT-mediated oxygen consumption and microvascular damage further increase tumor hypoxia and, thus, impede therapeutic outcomes. In recent years, numerous investigations have focused on strategies for overcoming this drawback of PDT. These efforts, which are summarized in this review, have produced many innovative methods to avoid the limits of PDT associated with hypoxia.

Visible-light photocatalysis is a rapidly developing and powerful strategy to initiate organic transformations, as it closely adheres to the tenants of green and sustainable chemistry. Generally, most visible-light-induced photochemical reactions occur through single-electron transfer (SET) pathways. Recently, visible-light-induced energy-transfer (EnT) reactions have received considerable attentions from the synthetic community as this strategy provides a distinct reaction pathway, and remarkable achievements have been made in this field. In this Review, we highlight the most recent advances in visible-light-induced EnT reactions.

The use of electricity instead of stoichiometric amounts of oxidizers or reducing agents in synthesis is very appealing for economic and ecological reasons, and represents a major driving force for research efforts in this area. To use electron transfer at the electrode for a successful transformation in organic synthesis, the intermediate radical (cation/anion) has to be stabilized. Its combination with other approaches in organic chemistry or concepts of contemporary synthesis allows the establishment of powerful synthetic methods. The aim in the 21st Century will be to use as little fossil carbon as possible and, for this reason, the use of renewable sources is becoming increasingly important. The direct conversion of renewables, which have previously mainly been incinerated, is of increasing interest. This Review surveys many of the recent seminal important developments which will determine the future of this dynamic emerging field.

Abstract Endowing materials with specific functions that are not readily available is always of great importance, but extremely challenging. Co 4 N, with its beneficial metallic characteristics, has been proved to be highly active for the oxidation of water, while it is notoriously poor for catalyzing the hydrogen evolution reaction (HER), because of its unfavorable d‐band energy level. Herein, we successfully endow Co 4 N with prominent HER catalytic capability by tailoring the positions of the d‐band center through transition‐metal doping. The V‐doped Co 4 N nanosheets display an overpotential of 37 mV at 10 mA cm −2 , which is substantially better than Co 4 N and even close to the benchmark Pt/C catalysts. XANES, UPS, and DFT calculations consistently reveal the enhanced performance is attributed to the downshift of the d‐band center, which helps facilitate the H desorption. This concept could provide valuable insights into the design of other catalysts for HER and beyond.

Cancer immunotherapies that train or stimulate the inherent immunological systems to recognize, attack, and eradicate tumor cells with minimal damage to healthy cells have demonstrated promising clinical responses in recent years. However, most of these immunotherapeutic strategies only benefit a small subset of patients and cause systemic autoimmune side effects in some patients. Immunogenic cell death (ICD)-inducing modalities not only directly kill cancer cells but also induce antitumor immune responses against a broad spectrum of solid tumors. Such strategies for generating vaccine-like functions could be used to stimulate a "cold" tumor microenvironment to become an immunogenic, "hot" tumor microenvironment, working in synergy with immunotherapies to increase patient response rates and lead to successful treatment outcomes. This Minireview will focus on nanoparticle-based treatment modalities that can induce and enhance ICD to potentiate cancer immunotherapy.

Abstract Cost‐effective aqueous rechargeable batteries are attractive alternatives to non‐aqueous cells for stationary grid energy storage. Among different aqueous cells, zinc‐ion batteries (ZIBs), based on Zn 2+ intercalation chemistry, stand out as they can employ high‐capacity Zn metal as the anode material. Herein, we report a layered calcium vanadium oxide bronze as the cathode material for aqueous Zn batteries. For the storage of the Zn 2+ ions in the aqueous electrolyte, we demonstrate that the calcium‐based bronze structure can deliver a high capacity of 340 mA h g −1 at 0.2 C, good rate capability, and very long cycling life (96 % retention after 3000 cycles at 80 C). Further, we investigate the Zn 2+ storage mechanism, and the corresponding electrochemical kinetics in this bronze cathode. Finally, we show that our Zn cell delivers an energy density of 267 W h kg −1 at a power density of 53.4 W kg −1 .

The fast-moving fields of photoredox and photocatalysis have recently provided fresh opportunities to expand the potential of synthetic organic chemistry. Advances in light-mediated processes have mainly been guided so far by empirical findings and the quest for reaction invention. The general perception, however, is that photocatalysis is entering a more mature phase where the combination of experimental and mechanistic studies will play a dominant role in sustaining further innovation. This Review outlines the key mechanistic studies to consider when developing a photochemical process, and the best techniques available for acquiring relevant information. The discussion will use selected case studies to highlight how mechanistic investigations can be instrumental in guiding the invention and development of synthetically useful photocatalytic transformations.

Abstract It remains highly desired but a great challenge to achieve atomically dispersed metals in high loadings for efficient catalysis. Now porphyrinic metal–organic frameworks (MOFs) have been synthesized based on a novel mixed‐ligand strategy to afford high‐content (1.76 wt %) single‐atom (SA) iron‐implanted N‐doped porous carbon (Fe SA ‐N‐C) via pyrolysis. Thanks to the single‐atom Fe sites, hierarchical pores, oriented mesochannels and high conductivity, the optimized Fe SA ‐N‐C exhibits excellent oxygen reduction activity and stability, surpassing almost all non‐noble‐metal catalysts and state‐of‐the‐art Pt/C, in both alkaline and more challenging acidic media. More far‐reaching, this MOF‐based mixed‐ligand strategy opens a novel avenue to the precise fabrication of efficient single‐atom catalysts.

The ubiquity of polymeric materials in daily life comes with an increased fire risk, and sustained research into efficient flame retardants is key to ensuring the safety of the populace and material goods from accidental fires. Phosphorus, a versatile and effective element for use in flame retardants, has the potential to supersede the halogenated variants that are still widely used today: current formulations employ a variety of modes of action and methods of implementation, as additives or as reactants, to solve the task of developing flame-retarding polymeric materials. Phosphorus-based flame retardants can act in both the gas and condensed phase during a fire. This Review investigates how current phosphorus chemistry helps in reducing the flammability of polymers, and addresses the future of sustainable, efficient, and safe phosphorus-based flame-retardants from renewable sources.

This description of "soft robotics" is not intended to be a conventional review, in the sense of a comprehensive technical summary of a developing field. Rather, its objective is to describe soft robotics as a new field-one that offers opportunities to chemists and materials scientists who like to make "things" and to work with macroscopic objects that move and exert force. It will give one (personal) view of what soft actuators and robots are, and how this class of soft devices fits into the more highly developed field of conventional "hard" robotics. It will also suggest how and why soft robotics is more than simply a minor technical "tweak" on hard robotics and propose a unique role for chemistry, and materials science, in this field. Soft robotics is, at its core, intellectually and technologically different from hard robotics, both because it has different objectives and uses and because it relies on the properties of materials to assume many of the roles played by sensors, actuators, and controllers in hard robotics.

The adhesion of some marine organisms to almost any kind of surface in wet conditions has aroused increasing interest in recent decades. Numerous fundamental studies have been performed to understand the scientific basis of this behaviour, with catechols having been found to play a key role. Several novel bio-inspired adhesives and coatings with value-added performances have been developed by taking advantage of the knowledge gained from these studies. To date there has been no detailed overview focusing exclusively on the complex mode of action of these materials. The aim of this Review is to present recent investigations that elucidate the origin of the strong and versatile adsorption capacities of the catechol moiety and the effects of extrinsic factors that play important roles in the overall adhesion process, such as pH value, solvent, and the presence of metal ions. The aim is to detail the chemistry behind the astonishing properties of natural and synthetic catechol-based adhesive materials.

Abstract Safe and rechargeable lithium metal batteries have been difficult to achieve because of the formation of lithium dendrites. Herein an emerging electrolyte based on a simple solvation strategy is proposed for highly stable lithium metal anodes in both coin and pouch cells. Fluoroethylene carbonate (FEC) and lithium nitrate (LiNO 3 ) were concurrently introduced into an electrolyte, thus altering the solvation sheath of lithium ions, and forming a uniform solid electrolyte interphase (SEI), with an abundance of LiF and LiN x O y on a working lithium metal anode with dendrite‐free lithium deposition. Ultrahigh Coulombic efficiency (99.96 %) and long lifespans (1000 cycles) were achieved when the FEC/LiNO 3 electrolyte was applied in working batteries. The solvation chemistry of electrolyte was further explored by molecular dynamics simulations and first‐principles calculations. This work provides insight into understanding the critical role of the solvation of lithium ions in forming the SEI and delivering an effective route to optimize electrolytes for safe lithium metal…

Abstract Covalent organic frameworks (COFs) are attractive candidates for advanced water‐treatment membranes owing to their high porosity and well‐organized channel structures. Herein, the continuous two‐dimensional imine‐linked COF‐LZU1 membrane with a thickness of only 400 nm was prepared on alumina tubes by in situ solvothermal synthesis. The membrane shows excellent water permeance (ca. 760 L m −2 h −1 MPa −1 ) and favorable rejection rates exceeding 90 % for water‐soluble dyes larger than 1.2 nm. The water permeance through the COF‐LZU1 membrane is much higher than that of most membranes with similar rejection rates. Long‐time operation demonstrates the outstanding stability of the COF‐LZU1 membrane. As the membrane has no selectivity for hydrated salt ions (selectivity <12 %), it is also suitable for the purification of dye products from saline solutions. The excellent performance and the outstanding water stability render the COF‐LZU1 membrane an interesting system for water purification.

Abstract Two‐dimensional (2D) titanium carbide (Ti 3 C 2 ) is emerging as an important member of the MXene family. However, fluoride‐based synthetic procedures remain an impediment to the practical applications of this promising class of materials. Here we demonstrate an efficient fluoride‐free etching method based on the anodic corrosion of titanium aluminium carbide (Ti 3 AlC 2 ) in a binary aqueous electrolyte. The dissolution of aluminium followed by in situ intercalation of ammonium hydroxide results in the extraction of carbide flakes (Ti 3 C 2 T x , T=O, OH) with sizes up to 18.6 μm and high yield (over 90 %) of mono‐ and bilayers. All‐solid‐state supercapacitor based on exfoliated sheets exhibits high areal and volumetric capacitances of 220 mF cm −2 and 439 F cm −3 , respectively, at a scan rate of 10 mV s −1 , superior to those of LiF/HCl‐etched MXenes. Our strategy paves a safe way to the scalable synthesis and application of MXene materials.

Abstract Lithium metal (Li 0 ) rechargeable batteries (LMBs), such as systems with a Li 0 anode and intercalation and/or conversion type cathode, lithium‐sulfur (Li‐S), and lithium‐oxygen (O 2 )/air (Li‐O 2 /air) batteries, are becoming increasingly important for electrifying the modern transportation system, with the aim of sustainable mobility. Although some rechargeable LMBs (e.g. Li 0 /LiFePO 4 batteries from Bolloré Bluecar, Li‐S batteries from OXIS Energy and Sion Power) are already commercially viable in niche applications, their large‐scale deployment is hampered by a number of formidable challenges, including growth of lithium dendrites, electrolyte instability towards high voltage intercalation‐type cathodes, the poor electronic and ionic conductivities of sulfur (S 8 ) and O 2 , as well as their corresponding reduction products (e.g. Li 2 S and Li 2 O), dissolution, and shuttling of polysulfide (PS) intermediates. This leads to a short lifecycle, low coulombic/energy efficiency, poor safety, and a high self‐discharge rate. The use of electrolyte additives is considered…

Abstract As electron transfer to CO 2 is generally considered to be the critical step during the activation of CO 2 , it is important to develop approaches to engineer the electronic properties of catalysts to improve their performance in CO 2 electrochemical reduction. Herein, we developed an efficient strategy to facilitate CO 2 activation by introducing oxygen vacancies into electrocatalysts with electronic‐rich surface. ZnO nanosheets rich in oxygen vacancies exhibited a current density of −16.1 mA cm −2 with a Faradaic efficiency of 83 % for CO production. Based on density functional theory (DFT) calculations, the introduction of oxygen vacancies increased the charge density of ZnO around the valence band maximum, resulting in the enhanced activation of CO 2 . Mechanistic studies further revealed that the enhancement of CO production by introducing oxygen vacancies into ZnO nanosheets originated from the increased binding strength of CO 2 and the eased CO 2 activation.

Abstract Photoelectrochemical (PEC) water splitting is a promising method for storing solar energy in the form of hydrogen fuel, but it is greatly hindered by the sluggish kinetics of the oxygen evolution reaction (OER). Herein, a facile solution impregnation method is developed for growing ultrathin (2 nm) highly crystalline β‐FeOOH nanolayers with abundant oxygen vacancies on BiVO4 photoanodes. These exhibited a remarkable photocurrent density of 4.3 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode (RHE), AM 1.5 G), which is approximately two times higher than that of amorphous FeOOH fabricated by electrodeposition. Systematic studies reveal that the excellent PEC activity should be attributed to their ultrathin crystalline structure and abundant oxygen vacancies, which could effectively facilitate the hole transport/trapping and provide more active sites for water oxidation.

Abstract Electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions provides an intriguing picture for the conversion of N 2 into NH 3 . However, electrocatalytic NRR mainly relies on metal‐based catalysts, and it remains a grand challenge in enabling effective N 2 activation on metal‐free catalysts. Here we report a defect engineering strategy to realize effective NRR performance (NH 3 yield: 8.09 μg h −1 mg −1 cat. , Faradaic efficiency: 11.59 %) on metal‐free polymeric carbon nitride (PCN) catalyst. Illustrated by density functional theory calculations, dinitrogen molecule can be chemisorbed on as‐engineered nitrogen vacancies of PCN through constructing a dinuclear end‐on bound structure for spatial electron transfer. Furthermore, the N−N bond length of adsorbed N 2 increases dramatically, which corresponds to “strong activation” system to reduce N 2 into NH 3 . This work also highlights the significance of defect engineering for improving electrocatalysts with weak N 2 adsorption and activation ability.

Abstract Biopolymer aerogels were among the first aerogels produced, but only in the last decade has research on biopolymer and biopolymer–composite aerogels become popular, motivated by sustainability arguments, their unique and tunable properties, and ease of functionalization. Biopolymer aerogels and open‐cell foams have great potential for classical aerogel applications such as thermal insulation, as well as emerging applications in filtration, oil–water separation, CO2 capture, catalysis, and medicine. The biopolymer aerogel field today is driven forward by empirical materials discovery at the laboratory scale, but requires a firmer theoretical basis and pilot studies to close the gap to market. This Review includes a database with over 3800 biopolymer aerogel properties, evaluates the state of the biopolymer aerogel field, and critically discusses the scientific, technological, and commercial barriers to the commercialization of these exciting materials.

Abstract Fluorooxoborates, benefiting from the large optical band gap, high anisotropy, and ever‐greater possibility to form non‐centrosymmetric structures activated by the large polarization of [BO x F 4− x ] ( x +1)− building blocks, have been considered as the new fertile fields for searching the ultraviolet (UV) and deep‐UV nonlinear optical (NLO) materials. Herein, we report the first asymmetric alkaline‐earth metal fluorooxoborate SrB 5 O 7 F 3 , which is rationally designed by taking the classic Sr 2 Be 2 B 2 O 7 (SBBO) as a maternal structure. Its [B 5 O 9 F 3 ] 6− fundamental building block with near‐planar configuration composed by two edge‐sharing [B 3 O 6 F 2 ] 5− rings in SrB 5 O 7 F 3 has not been reported in any other borates. Solid state 19 F and 11 B magic‐angle spinning NMR spectroscopy verifies the presence of covalent B−F bonds in SrB 5 O 7 F 3 . Property characterizations reveal that SrB 5 O 7 F 3 possesses the optical properties required for deep‐UV NLO applications, which make SrB 5 O 7 F 3 a promising crystal that could produce deep‐UV coherent light by the…

Abstract Crystalline and porous covalent organic frameworks (COFs) and metal‐organic frameworks (MOFs) materials have attracted enormous attention in the field of photocatalytic H 2 evolution due to their long‐range order structures, large surface areas, outstanding visible light absorbance, and tunable band gaps. In this work, we successfully integrated two‐dimensional (2D) COF with stable MOF. By covalently anchoring NH 2 ‐UiO‐66 onto the surface of TpPa‐1‐COF, a new type of MOF/COF hybrid materials with high surface area, porous framework, and high crystallinity was synthesized. The resulting hierarchical porous hybrid materials show efficient photocatalytic H 2 evolution under visible light irradiation. Especially, NH 2 ‐UiO‐66/TpPa‐1‐COF (4:6) exhibits the maximum photocatalytic H 2 evolution rate of 23.41 mmol g −1 h −1 (with the TOF of 402.36 h −1 ), which is approximately 20 times higher than that of the parent TpPa‐1‐COF and the best performance photocatalyst for H 2 evolution among various MOF‐ and COF‐based photocatalysts.

Abstract Developing high‐efficiency and affordable electrocatalysts for the sluggish oxygen evolution reaction (OER) remains a crucial bottleneck on the way to the practical applications of rechargeable energy storage technologies and water splitting for producing clean fuel (H 2 ). In recent years, NiFe‐based materials have proven to be excellent electrocatalysts for OER. Understanding the characteristics that affect OER activity and determining the OER mechanism are of vital importance for the development of OER electrocatalysts. Therefore, in situ characterization techniques performed under OER conditions are urgently needed to monitor the key intermediates together with identifying the OER active centers and phases. In this Minireview, recent advances regarding in situ techniques for the characterization of NiFe‐based electrocatalysts are thoroughly summarized, including Raman spectroscopy, X‐ray absorption spectroscopy, ambient pressure X‐ray photoelectron spectroscopy, Mössbauer spectroscopy, Ultraviolet–visible spectroscopy, differential electrochemical mass spectrometry, and…

Abstract The development of new nonlinear optical (NLO) materials for deep‐ultraviolet (DUV) applications is in great demand. However, the synthesis of an ideal DUV NLO crystal is a serious challenge. Herein, three new alkali‐metal fluorooxoborates, AB4O6F (A=K, Rb, and Cs, and a mixed cation between two of them), were successfully synthesized by cation regulation. It is found that all reported compounds exhibit short UV absorption edges (<190 nm), and show second harmonic generation (SHG) responses ranging from 0.8 to 1.9 KH2PO4 (KDP). Interestingly, by judicious selection of the A‐site alkali‐metal cations, the arrangement of NLO‐active structural units is fine‐tuned to an optimal configuration, which contributes to large SHG responses.

In the last few decades, "unusual" noncovalent interactions like anion-π and halogen bonding have emerged as interesting alternatives to the ubiquitous hydrogen bonding in many research areas. This is also true, to a somewhat lesser extent, for chalcogen bonding, the noncovalent interaction involving Lewis acidic chalcogen centers. Herein, we aim to provide an overview on the use of chalcogen bonding in crystal engineering and in solution, with a focus on the recent developments concerning intermolecular chalcogen bonding in solution-phase applications. In the solid phase, chalcogen bonding has been used for the construction of nano-sized structures and the self-assembly of sophisticated self-complementary arrays. In solution, until very recently applications mostly focused on intramolecular interactions which stabilized the conformation of intermediates or reagents. In the last few years, intermolecular chalcogen bonding has increasingly also been exploited in solution, most notably in anion recognition and transport as well as in organic synthesis and organocatalysis.

Abstract Two‐dimensional (2D) heterostructured materials, combining the collective advantages of individual building blocks and synergistic properties, have spurred great interest as a new paradigm in materials science. The family of 2D transition‐metal carbides and nitrides, MXenes, has emerged as an attractive platform to construct functional materials with enhanced performance for diverse applications. Here, we synthesized 2D MoS 2 ‐on‐MXene heterostructures through in situ sulfidation of Mo 2 TiC 2 T x MXene. The computational results show that MoS 2 ‐on‐MXene heterostructures have metallic properties. Moreover, the presence of MXene leads to enhanced Li and Li 2 S adsorption during the intercalation and conversion reactions. These characteristics render the as‐prepared MoS 2 ‐on‐MXene heterostructures stable Li‐ion storage performance. This work paves the way to use MXene to construct 2D heterostructures for energy storage applications.

Abstract Driven by the inherent synthetic potential of CO 2 as an abundant, inexpensive and renewable C 1 chemical feedstock, the recent years have witnessed renewed interest in devising catalytic CO 2 fixations into organic matter. Although the formation of C−C bonds via catalytic CO 2 fixation remained rather limited for a long period of time, a close look into the recent literature data indicates that catalytic carboxylation reactions have entered a new era of exponential growth, evolving into a mature discipline that allows for streamlining the synthesis of carboxylic acids, building blocks of utmost relevance in industrial endeavors. These strategies have generally proven broadly applicability and convenient to perform. However, substantial challenges still need to be addressed reinforcing the need to cover metal‐catalyzed carboxylation area in a conceptual and concise manner, delineating the underlying new principles that are slowly emerging in this vibrant area of expertise.

Abstract This Review provides a comprehensive overview of LiNiO 2 (LNO), almost 30 years after its introduction as a cathode active material. We aim to highlight the physicochemical peculiarities that make LNO a complex material in every aspect. We specifically stress the effect of the Li off‐stoichiometry (Li 1−z Ni 1+z O 2 ) on every property of LNO, especially the electrochemical ones. The key instability issues that plague the compound and the strategies that have been implemented so far to overcome them are discussed in detail. Finally, the open questions that remain to be addressed by the scientific community are summarized, and the research directions that seem the most promising to enable LNO to be fully exploited are elucidated.

Abstract N 2 fixation by the electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is regarded as a potential approach to achieve NH 3 production, which still heavily relies on the Haber–Bosch process at the cost of huge energy and massive production of CO 2 . A noble‐metal‐free Bi 4 V 2 O 11 /CeO 2 hybrid with an amorphous phase (BVC‐A) is used as the cathode for electrocatalytic NRR. The amorphous Bi 4 V 2 O 11 contains significant defects, which play a role as active sites. The CeO 2 not only serves as a trigger to induce the amorphous structure, but also establishes band alignment with Bi 4 V 2 O 11 for rapid interfacial charge transfer. Remarkably, BVC‐A shows outstanding electrocatalytic NRR performance with high average yield (NH 3 : 23.21 μg h −1 mg −1 cat. , Faradaic efficiency: 10.16 %) under ambient conditions, which is superior to the Bi 4 V 2 O 11 /CeO 2 hybrid with crystalline phase (BVC‐C) counterpart.

Abstract NH3 synthesis by the electrocatalytic N2 reduction reaction (NRR) under ambient conditions is an appealing alternative to the currently employed industrial method—the Haber–Bosch process—that requires high temperature and pressure. We report single Mo atoms anchored to nitrogen‐doped porous carbon as a cost‐effective catalyst for the NRR. Benefiting from the optimally high density of active sites and hierarchically porous carbon frameworks, this catalyst achieves a high NH3 yield rate (34.0±3.6 μg h−1 mgcat.−1) and a high Faradaic efficiency (14.6±1.6 %) in 0.1 m KOH at room temperature. These values are considerably higher compared to previously reported non‐precious‐metal electrocatalysts. Moreover, this catalyst displays no obvious current drop during a 50 000 s NRR, and high activity and durability are achieved in 0.1 m HCl. The findings provide a promising lead for the design of efficient and robust single‐atom non‐precious‐metal catalysts for the electrocatalytic NRR.

Conjugated carbon nitride (CN) is an emerging and promising semiconductor photocatalyst for water photolysis owing to its unique properties. However, the traditional thermally induced polymerization of N-containing precursors typically produces melon-based CN solids with amorphous or semi-crystalline structures with only moderate photocatalytic performance. Many strategies have been developed to prepare crystalline CNs (CCNs), such as high-temperature and high-pressure routes, ionothermal synthesis, and microwave-assisted synthesis. In this Minireview, we summarize the progress that has been made in the synthesis of CCNs and their application in photocatalytic water splitting reactions. Three kinds of CCNs are mainly discussed according to their polymeric subunits. Challenges associated with CCNs and their future development are also included.

A small-molecule fluorophore FD-1080 with both excitation and emission in the NIR-II region has been successfully synthesized for in vivo imaging. A heptamethine structure is designed to shift the absorption and emission into NIR-II region. Sulphonic and cyclohexene groups are introduced to enhance its water solubility and stability. The quantum yield of FD-1080 is 0.31 %, and can be increased to 5.94 % after combining with fetal bovine serum (FBS). Significantly, 1064 nm NIR-II excitation was demonstrated with the high tissue penetration depth and superior imaging resolution compared to previously reported NIR excitation from 650 nm to 980 nm. FD-1080 is not only capable of realizing non-invasive high-resolution deep-tissue hindlimb vasculature and brain vessel bioimaging, but also quantifying the respiratory rate based on the dynamic imaging of respiratory craniocaudal motion of the liver for the awake and anaesthetized mouse.

Abstract Solid‐state electrolytes have emerged as a promising alternative to existing liquid electrolytes for next generation Li‐ion batteries for better safety and stability. Of various types of solid electrolytes, composite polymer electrolytes exhibit acceptable Li‐ion conductivity due to the interaction between nanofillers and polymer. Nevertheless, the agglomeration of nanofillers at high concentration has been a major obstacle for improving Li‐ion conductivity. In this study, we designed a three‐dimensional (3D) nanostructured hydrogel‐derived Li0.35La0.55TiO3 (LLTO) framework, which was used as a 3D nanofiller for high‐performance composite polymer Li‐ion electrolyte. The systematic percolation study revealed that the pre‐percolating structure of LLTO framework improved Li‐ion conductivity to 8.8×10−5 S cm−1 at room temperature.

Nanozymes have advantages over natural enzymes, such as facile production on large scale, long storage time, low costs, and high stability in harsh environments. Carbon nanomaterials (CNMs), including fullerenes, carbon nanotubes, graphene, carbon quantum dots, and graphene quantum dots, have become a star family in materials science. As a new class of nanozymes, the catalytic activity of CNMs and their hybrids has been extensively reported. In this Minireview, recent progress of CNMs based artificial enzymes, focusing on those with peroxidase-like activity, has been summarized. The enzymatic properties, catalytic mechanisms, and novel applications of CNM nanozymes in sensing, therapy, and environmental engineering are discussed in detail. Additionally, we also highlight the remaining challenges and unsolved problems. With the fast development of bionanotechnology, the unique enzymatic properties and advantages of CNM nanozymes have received much attention and will continue to be an active and challenging field for the years to come.

Abstract A biomimetic (titin protein molecular structure) strategy is reported for preparing transparent and healable elastomers featuring supertoughness (345 MJ m −3 ) and high tensile strength (44 MPa) after self‐healing enabled by hierarchical (single, double, and quadruple) hydrogen‐bonding moieties in the polymer backbone. The rigid domain containing hierarchical H‐bonds formed with urethane, urea, and 2‐ureido‐4[1H]‐pyrimidinone groups leads to a durable network structure that has enhanced mechanical properties and is also dynamic for rapid self‐healing. Healable polymers with hierarchical hydrogen‐bonding interactions show excellent recoverability and high energy dissipation owing to the durable interaction between polymer chains. This biomimetic strategy of using hierarchical hydrogen bonds as building blocks is an alternative approach for obtaining dynamic, strong, yet smart self‐healing polymers for heavy‐duty protection materials and wearable electronics.

The application of photochemistry to polymer and material science has led to the development of complex yet efficient systems for polymerization, polymer post-functionalization, and advanced materials production. Using light to activate chemical reaction pathways in these systems not only leads to exquisite control over reaction dynamics, but also allows complex synthetic protocols to be easily achieved. Compared to polymerization systems mediated by thermal, chemical, or electrochemical means, photoinduced polymerization systems can potentially offer more versatile methods for macromolecular synthesis. We highlight the utility of light as an energy source for mediating photopolymerization, and present some promising examples of systems which are advancing materials production through their exploitation of photochemistry.

Abstract The lithium metal anode is regarded as a promising candidate in next‐generation energy storage devices. Lithium nitrate (LiNO 3 ) is widely applied as an effective additive in ether electrolyte to increase the interfacial stability in batteries containing lithium metal anodes. However, because of its poor solubility LiNO 3 is rarely utilized in the high‐voltage window provided by carbonate electrolyte. Dissolution of LiNO 3 in carbonate electrolyte is realized through an effective solvation regulation strategy. LiNO 3 can be directly dissolved in an ethylene carbonate/diethyl carbonate electrolyte mixture by adding trace amounts of copper fluoride as a dissolution promoter. LiNO 3 protects the Li metal anode in a working high‐voltage Li metal battery. When a LiNi 0.80 Co 0.15 Al 0.05 O 2 cathode is paired with a Li metal anode, an extraordinary capacity retention of 53 % is achieved after 300 cycles (13 % after 200 cycles for LiNO 3 ‐free electrolyte) and a very high average Coulombic efficiency above 99.5 % is achieved at 0.5 C. The solvation chemistry of LiNO 3…

Long-lifetime room-temperature phosphorescence (RTP) materials are important for many applications, but they are highly challenging materials owing to the spin-forbidden nature of triplet exciton transitions. Herein, a facile, quick and gram-scale method for the preparation of ultralong RTP (URTP) carbon dots (CDs) was developed via microwave-assisted heating of ethanolamine and phosphoric acid aqueous solution. The CDs exhibit the longest RTP lifetime, 1.46 s (more than 10 s to naked eye) for CDs-based materials to date. The doping of N and P elements is critical for the URTP which is considered to be favored by a n→π* transition facilitating intersystem crossing (ISC) for effectively populating triplet excitons. In addition, possibilities of formation of hydrogen bonds in the interior of the CDs may also play a significant role in producing RTP. Potential applications of the URTP CDs in the fields of anti-counterfeiting and information protection are proposed and demonstrated.

Abstract Solar CO 2 reduction efficiency is largely limited by poor photoabsorption, sluggish electron–hole separation, and a high CO 2 activation barrier. Defect engineering was employed to optimize these crucial processes. As a prototype, BiOBr atomic layers were fabricated and abundant oxygen vacancies were deliberately created on their surfaces. X‐ray absorption near‐edge structure and electron paramagnetic resonance spectra confirm the formation of oxygen vacancies. Theoretical calculations reveal the creation of new defect levels resulting from the oxygen vacancies, which extends the photoresponse into the visible‐light region. The charge delocalization around the oxygen vacancies contributes to CO 2 conversion into COOH* intermediate, which was confirmed by in situ Fourier‐transform infrared spectroscopy. Surface photovoltage spectra and time‐resolved fluorescence emission decay spectra indicate that the introduced oxygen vacancies promote the separation of carriers. As a result, the oxygen‐deficient BiOBr atomic layers achieve visible‐light‐driven CO 2 reduction with a CO…

Abstract The development of efficient and low energy‐consumption catalysts for CO2 conversion is desired, yet remains a great challenge. Herein, a class of novel hollow porous carbons (HPC), featuring well dispersed dopants of nitrogen and single Zn atoms, have been fabricated, based on the templated growth of a hollow metal–organic framework precursor, followed by pyrolysis. The optimized HPC‐800 achieves efficient catalytic CO2 cycloaddition with epoxides, under light irradiation, at ambient temperature, by taking advantage of an ultrahigh loading of (11.3 wt %) single‐atom Zn and uniform N active sites, high‐efficiency photothermal conversion as well as the hierarchical pores in the carbon shell. As far as we know, this is the first report on the integration of the photothermal effect of carbon‐based materials with single metal atoms for catalytic CO2 fixation.

The union of photoredox and nickel catalysis has resulted in a renaissance in radical chemistry as well as in the use of nickel-catalyzed transformations, specifically for carbon-carbon bond formation. Collectively, these advances address the longstanding challenge of late-stage cross-coupling of functionalized alkyl fragments. Empowered by the notion that photocatalytically generated alkyl radicals readily undergo capture by Ni complexes, wholly new feedstocks for cross-coupling have been realized. Herein, we highlight recent developments in several types of alkyl cross-couplings that are accessible exclusively through this approach.

Polyoxometalates (POMs) are an emerging class of inorganic metal oxides, which over the last decades demonstrated promising biological activities by the virtue of their great diversity in structures and properties. They possess high potential for the inhibition of various tumor types; however, their unspecific interactions with biomolecules and toxicity impede their clinical usage. The current focus of the field of biologically active POMs lies on organically functionalized and POM-based nanocomposite structures as these hybrids show enhanced anticancer activity and significantly reduced toxicity towards normal cells in comparison to unmodified POMs. Although the antitumor activity of POMs is well documented, their mechanisms of action are still not well understood. In this Review, an overview is given of the cytotoxic effects of POMs with a special focus on POM-based hybrid and nanocomposite structures. Furthermore, we aim to provide proposed mode of actions and to identify molecular targets. POMs are expected to develop into the next generation of anticancer drugs that selectively…

Polymer carbon dots (PCDs) are proposed as a new class of room-temperature phosphorescence (RTP) materials. The abundant energy levels in PCDs increase the probability of intersystem crossing (ISC) and their covalently crosslinked framework structures greatly suppress the nonradiative transitions. The efficient methods allow the manufacture of PCDs with unique RTP properties in air without additional metal complexation or complicated matrix composition. They thus provide a route towards the rational design of metal-free RTP materials that may be synthesized easily. Furthermore, we find that RTP is associated with a crosslink-enhanced emission (CEE) effect, which provides further routes to design improved PCDs with diverse RTP performance. Our results show the potential of PCDs as a universal route to achieve effective metal-free RTP.

Abstract Two Pt single‐atom catalysts (SACs) of Pt‐GDY1 and Pt‐GDY2 were prepared on graphdiyne (GDY)supports. The isolated Pt atoms are dispersed on GDY through the coordination interactions between Pt atoms and alkynyl C atoms in GDY, with the formation of five‐coordinated C 1 ‐Pt‐Cl 4 species in Pt‐GDY1 and four‐coordinated C 2 ‐Pt‐Cl 2 species in Pt‐GDY2. Pt‐GDY2 shows exceptionally high catalytic activity for the hydrogen evolution reaction (HER), with a mass activity up to 3.3 and 26.9 times more active than Pt‐GDY1 and the state‐of‐the‐art commercial Pt/C catalysts, respectively. Pt‐GDY2 possesses higher total unoccupied density of states of Pt 5d orbital and close to zero value of Gibbs free energy of the hydrogen adsorption (|Δ |) at the Pt active sites, which are responsible for its excellent catalytic performance. This work can help better understand the structure–catalytic activity relationship in Pt SACs.

Abstract Single Fe atoms dispersed on hierarchically structured porous carbon (SA‐Fe‐HPC) frameworks are prepared by pyrolysis of unsubstituted phthalocyanine/iron phthalocyanine complexes confined within micropores of the porous carbon support. The single‐atom Fe catalysts have a well‐defined atomic dispersion of Fe atoms coordinated by N ligands on the 3D hierarchically porous carbon support. These SA‐Fe‐HPC catalysts are comparable to the commercial Pt/C electrode even in acidic electrolytes for oxygen reduction reaction (ORR) in terms of the ORR activity ( E 1/2 =0.81 V), but have better long‐term electrochemical stability (7 mV negative shift after 3000 potential cycles) and fuel selectivity. In alkaline media, the SA‐Fe‐HPC catalysts outperform the commercial Pt/C electrode in ORR activity ( E 1/2 =0.89 V), fuel selectivity, and long‐term stability (1 mV negative shift after 3000 potential cycles). Thus, these nSA‐Fe‐HPCs are promising non‐platinum‐group metal ORR catalysts for fuel‐cell technologies.

For over two decades bulk-heterojunction polymer solar cell (BHJ-PSC) research was dominated by donor:acceptor BHJ blends based on polymer donors and fullerene molecular acceptors. This situation has changed recently, with non-fullerene PSCs developing very rapidly. The power conversion efficiencies of non-fullerene PSCs have now reached over 15 %, which is far above the most efficient fullerene-based PSCs. Among the various non-fullerene PSCs, all-polymer solar cells (APSCs) based on polymer donor-polymer acceptor BHJs have attracted growing attention, due to the following attractions: 1) large and tunable light absorption of the polymer donor/polymer acceptor pair; 2) robustness of the BHJ film morphology; 3) compatibility with large scale/large area manufacturing; 4) long-term stability of the cell to external environmental and mechanical stresses. This Minireview highlights the opportunities offered by APSCs, selected polymer families suitable for these devices with optimization to enhance the performance further, and discusses the challenges facing APSC development for…

Abstract Developing an efficient single‐atom material (SAM) synthesis and exploring the energy‐related catalytic reaction are important but still challenging. A polymerization–pyrolysis–evaporation (PPE) strategy was developed to synthesize N‐doped porous carbon (NPC) with anchored atomically dispersed Fe‐N4 catalytic sites. This material was derived from predesigned bimetallic Zn/Fe polyphthalocyanine. Experiments and calculations demonstrate the formed Fe‐N4 site exhibits superior trifunctional electrocatalytic performance for oxygen reduction, oxygen evolution, and hydrogen evolution reactions. In overall water splitting and rechargeable Zn–air battery devices containing the Fe‐N4 SAs/NPC catalyst, it exhibits high efficiency and extraordinary stability. This current PPE method is a general strategy for preparing M SAs/NPC (M=Co, Ni, Mn), bringing new perspectives for designing various SAMs for catalytic application.

Abstract Rechargeable batteries have been used to power various electric devices and store energy from renewables, but their toxic components (namely, electrode materials, electrolyte, and separator) generally cause serious environment issues when disused. Such toxicity characteristic makes them difficult to power future wearable electronic devices. Now an environmentally friendly and highly safe rechargeable battery, based on a pyrene‐4,5,9,10‐tetraone (PTO) cathode and zinc anode in mild aqueous electrolyte is presented. The PTO‐cathode shows a high specific capacity (336 mAh g −1 ) for Zn 2+ storage with fast kinetics and high reversibility. Thus, the PTO//Zn full cell exhibits a high energy density (186.7 Wh kg −1 ), supercapacitor‐like power behavior and long‐term lifespan (over 1000 cycles). Moreover, a belt‐shaped PTO//Zn battery with robust mechanical durability and remarkable flexibility is first fabricated to clarify its potential application in wearable electronic devices.

Abstract Halide perovskite quantum dots (QDs) have great potential in photocatalytic applications if their low charge transportation efficiency and chemical instability can be overcome. To circumvent these obstacles, we anchored CsPbBr 3 QDs (CPB) on NH x ‐rich porous g‐C 3 N 4 nanosheets (PCN) to construct the composite photocatalysts via N−Br chemical bonding. The 20 CPB‐PCN (20 wt % of QDs) photocatalyst exhibits good stability and an outstanding yield of 149 μmol h −1 g −1 in acetonitrile/water for photocatalytic reduction of CO 2 to CO under visible light irradiation, which is around 15 times higher than that of CsPbBr 3 QDs. This study opens up new possibilities of using halide perovskite QDs for photocatalytic application.

Abstract A key challenge faced by organic electrodes is how to promote the redox reactions of functional groups to achieve high specific capacity and rate performance. Here, we report a two‐dimensional (2D) microporous covalent–organic framework (COF), poly(imide‐benzoquinone), via in situ polymerization on graphene (PIBN‐G) to function as a cathode material for lithium‐ion batteries (LIBs). Such a structure favors charge transfer from graphene to PIBN and full access of both electrons and Li+ ions to the abundant redox‐active carbonyl groups, which are essential for battery reactions. This enables large reversible specific capacities of 271.0 and 193.1 mAh g−1 at 0.1 and 10 C, respectively, and retention of more than 86 % after 300 cycles. The discharging/charging process successively involves 8 Li+ and 2 Li+ in the carbonyl groups of the respective imide and quinone groups. The structural merits of PIBN‐G will trigger more investigations into the designable and versatile COFs for electrochemistry.

Metal sites play an essential role in both electrocatalytic and photocatalytic energy conversion. The highly ordered arrangements of the organic linkers and metal nodes as well as the well-defined pore structures of metal-organic frameworks (MOFs) make them ideal substrates to support atomically dispersed metal sites (ADMSs) located in their metal nodes, linkers, and pores. Porous carbon materials doped with ADMSs can be derived from these ADMS-incorporating MOF precursors through controlled treatments. These ADMSs incorporated in pristine MOFs and MOF-derived carbon materials possess unique advantages over molecular or bulk metal-based catalysts and bridge the gap between homogeneous and heterogeneous catalysts for energy-conversion applications. This Review presents recent progress in the design and incorporation of ADMSs in MOFs and MOF-derived materials for energy-conversion applications.

Abstract Iron‐substituted CoOOH porous nanosheet arrays grown on carbon fiber cloth (denoted as FexCo1−xOOH PNSAs/CFC, 0≤x≤0.33) with 3D hierarchical structures are synthesized by in situ anodic oxidation of α‐Co(OH)2 NSAs/CFC in solution of 0.01 m (NH4)2Fe(SO4)2. X‐ray absorption fine spectra (XAFS) demonstrate that CoO6 octahedral structure in CoOOH can be partially substituted by FeO6 octahedrons during the transformation from α‐Co(OH)2 to FexCo1−xOOH, and this is confirmed for the first time in this study. The content of Fe in FexCo1−xOOH, no more than 1/3 of Co, can be controlled by adjusting the in situ anodic oxidation time. Fe0.33Co0.67OOH PNSAs/CFC shows superior OER electrocatalytic performance, with a low overpotential of 266 mV at 10 mA cm−2, small Tafel slope of 30 mV dec−1, and high durability.

Abstract Photocatalytic water splitting requires separation of the mixed H 2 and O 2 products and is often hampered by the sluggish O 2 ‐producing half reaction. An approach is now reported to address these issues by coupling the H 2 ‐producing half reaction with value‐added benzylamine oxidation reaction using metal–organic framework (MOF) composites. Upon MOF photoexcitation, the electrons rapidly reduce the protons to generate H 2 and the holes promote considerable benzylamine oxidation to N‐benzylbenzaldimine with high selectivity. Further experimental characterizations and theoretical calculation reveal that the highly conjugated s‐triazine strut in the MOF structure is crucial to the efficient charge separation and excellent photocatalytic activity.

Abstract The low structural stability of hydrogen‐bonded organic frameworks (HOFs) is a thorny issue retarding the development of HOFs. A rational design approach is now proposed for construction of a stable HOF. The resultant HOF (PFC‐1) exhibits high surface area of 2122 m2 g−1 and excellent chemical stability (intact in concentrated HCl for at least 117 days). A new method of acid‐assisted crystalline redemption is used to readily cure the thermal damage to PFC‐1. With periodic integration of photoactive pyrene in the robust framework, PFC‐1 can efficiently encapsulate Doxorubicin (Doxo) for synergistic chemo‐photodynamic therapy, showing comparable therapeutic efficacy with the commercial Doxo yet considerably lower cytotoxicity. This work demonstrates the notorious stability issue of HOFs can be properly addressed through rational design, paving a way to develop robust HOFs and offering promising application perspectives.

Abstract Constructing efficient catalysts for the N 2 reduction reaction (NRR) is a major challenge for artificial nitrogen fixation under ambient conditions. Herein, inspired by the principle of “like dissolves like”, it is demonstrated that a member of the nitrogen family, well‐exfoliated few‐layer black phosphorus nanosheets (FL‐BP NSs), can be used as an efficient nonmetallic catalyst for electrochemical nitrogen reduction. The catalyst can achieve a high ammonia yield of 31.37 μg h −1 mg −1 cat. under ambient conditions. Density functional theory calculations reveal that the active orbital and electrons of zigzag and diff‐zigzag type edges of FL‐BP NSs enable selective electrocatalysis of N 2 to NH 3 via an alternating hydrogenation pathway. This work proves the feasibility of using a nonmetallic simple substance as a nitrogen‐fixing catalyst and thus opening a new avenue towards the development of more efficient metal‐free catalysts.

Abstract Photocatalytic conversion of diluted CO2 into solar fuel is highly appealing yet still in its infancy. Herein, we demonstrate the metal‐node‐dependent performance for photoreduction of diluted CO2 by constructing Ni metal–organic framework (MOF) monolayers (Ni MOLs). In diluted CO2 (10 %), Ni MOLs exhibit a highest apparent quantum yield of 1.96 % with a CO selectivity of 96.8 %, which not only exceeds reported systems in diluted CO2 but also is superior to most catalysts in pure CO2. Whereas isostructural Co MOLs is almost inactive in diluted CO2, indicating the performance is dependent on the metal nodes. Experimental and theoretical investigations show that strong CO2 binding affinity of Ni MOLs is the crucial factor, which stabilizes the Ni‐CO2 adducts and facilitates CO2‐to‐CO conversion.

Abstract The binding strength of reactive intermediates with catalytically active sites plays a crucial role in governing catalytic performance of electrocatalysts. NiFe hydroxide offers efficient oxygen evolution reaction (OER) catalysis in alkaline electrolyte, however weak binding of oxygenated intermediates on NiFe hydroxide still badly limits its catalytic activity. Now, a facile ball‐milling method was developed to enhance binding strength of NiFe hydroxide to oxygenated intermediates via generating tensile strain, which reduced the anti‐bonding filling states in the d orbital and thus facilitated oxygenated intermediates adsorption. The NiFe hydroxide with tensile strain increasing after ball‐milling exhibits an OER onset potential as low as 1.44 V (vs. reversible hydrogen electrode) and requires only a 270 mV overpotential to reach a water oxidation current density of 10 mA cm −2 .

The activation of carbon-fluorine (C-F) bonds is an important topic in synthetic organic chemistry. Metal-mediated and -catalyzed elimination of β- or α-fluorine proceeds under milder conditions than oxidative addition to C-F bonds. The β- or α-fluorine elimination is initiated from organometallic intermediates having fluorine substituents on carbon atoms β or α to metal centers, respectively. Transformations through these elimination processes (C-F bond cleavage), which are typically preceded by carbon-carbon (or carbon-heteroatom) bond formation, have been increasingly developed in the past five years as C-F bond activation methods. In this Minireview, we summarize the applications of transition-metal-mediated and -catalyzed fluorine elimination to synthetic organic chemistry from a historical perspective with early studies and from a systematic perspective with recent studies.

Abstract Rechargeable aqueous zinc batteries are promising energy‐storage systems for grid applications. Highly conductive polyaniline (PANI) is a potential cathode, but it tends to deactivate in electrolytes with low acidity (i.e. pH >1) owing to deprotonation of the polymer. In this study, we synthesized a sulfo‐self‐doped PANI electrode by a facile electrochemical copolymerization process. The −SO3− self‐dopant functions as an internal proton reservoir to ensure a highly acidic local environment and facilitate the redox process in the weakly acidic ZnSO4 electrolyte. In a full zinc cell, the self‐doped PANI cathode provided a high capacity of 180 mAh g−1, excellent rate performance of 70 % capacity retention with a 50‐fold current‐density increase, and a long cycle life of over 2000 cycles with coulombic efficiency close to 100 %. Our study opens a door for the use of conducting polymers as cathode materials for high‐performance rechargeable zinc batteries.

Electrocatalytic water splitting is one of the most promising sustainable energy conversion technologies, but is limited by the sluggish electrochemical reactions. Inorganic nanomaterials have been widely used as efficient catalysts for promoting the electrochemical kinetics. Several approaches to optimize the activities of these nanocatalysts have been developed. The electronic structures of the catalysts play a pivotal role in governing the activity and thus have been identified as an essential descriptor. However, the underlying working mechanisms related to the refined electronic structures remain elusive. To establish the structure-electronic-behavior-activity relationship, a comprehensive overview of the developed strategies to regulate the electronic structures is presented, emphasizing the surface modification, strain, phase transition, and heterostructure. Current challenges to the fundamental understanding of electron behaviors in the nanocatalysts are fully discussed.

Since the discovery of the liquid-crystalline state in 1888, liquid crystal science has made great advances through fusion with various technologies and disciplines. Recently, new molecular design strategies and new self-assembled structures have been developed as a result of the progress made in synthetic procedures and characterization techniques. Since these liquid crystals exhibit new functions and properties derived from their nanostructures and alignment, a variety of new functions for liquid crystals, such as transport for energy applications, separation for environmental applications, chromism, sensing, electrooptical effects, actuation, and templating have been proposed. This Review presents recent advances of liquid crystals that should contribute to the next generation of materials.

Abstract All‐inorganic perovskite solar cells with high efficiency and improved stability are promising for commercialization. A multistep solution‐processing method was developed to fabricate high‐purity inorganic CsPbBr3 perovskite films for use in efficient solar cells. By tuning the number of deposition cycles (n) of a CsBr solution, the phase conversion from CsPb2Br5 (n ≤3), to CsPbBr3 (n=4), and Cs4PbBr6 (n≥5) was optimized to achieve vertical‐ and monolayer‐aligned grains. Upon interfacial modification with graphene quantum dots, the all‐inorganic perovskite solar cell (without a hole‐transporting layer) achieved a power conversion efficiency (PCE) as high as 9.72 % under standard solar illumination conditions. Under challenging conditions, such as 90 % relative humidity (RH) at 25 °C or 80 °C at zero humidity, the optimized device retained 87 % PCE over 130 days or 95 % over 40 days, compared to the initial efficiency.

Cubosomes are highly stable nanoparticles formed from the lipid cubic phase and stabilized by a polymer based outer corona. Bicontinuous lipid cubic phases consist of a single lipid bilayer that forms a continuous periodic membrane lattice structure with pores formed by two interwoven water channels. Cubosome composition can be tuned to engineer pore sizes or include bioactive lipids, the polymer outer corona can be used for targeting and they are highly stable under physiological conditions. Compared to liposomes, the structure provides a significantly higher membrane surface area for loading of membrane proteins and small drug molecules. Owing to recent advances, they can be engineered in vitro in both bulk and nanoparticle formats with applications including drug delivery, membrane bioreactors, artificial cells, and biosensors. This review outlines recent advances in cubosome technology enabling their application and provides guidelines for the rational design of new systems for biomedical applications.

Abstract The electrochemical oxidation of the biorefinery product 5‐(hydroxymethyl)furfural (HMF) to 2,5‐furandicarboxylic acid (FDCA), an important platform chemical for the polymer industry, is receiving increasing interest. FDCA‐based polymers such as polyethylene 2,5‐furandicarboxylate (PEF) are sustainable candidates for replacing polyethylene terephthalate (PET). Herein, we report the highly efficient electrocatalytic oxidation of HMF to FDCA, using Ni foam modified with high‐surface‐area nickel boride (Ni x B) as the electrode. Constant potential electrolysis in combination with HPLC revealed a high faradaic efficiency of close to 100 % towards the production of FDCA with a yield of 98.5 %. Operando electrochemistry coupled to ATR‐IR spectroscopy indicated that HMF is oxidized preferentially via 5‐hydroxymethyl‐2‐furancarboxylic acid rather than via 2,5‐diformylfuran, which is in agreement with HPLC results. This study not only reports a low‐cost active electrocatalyst material for the electrochemical oxidation of HMF to FDCA, but additionally provides insight into the…

Polymeric carbon nitride (PCN), in either triazine or heptazine form, has been regarded as a promising metal-free, environmentally benign, and sustainable photocatalyst for solar hydrogen production. However, PCN in most cases only exhibits moderate activity owing to its inherent properties, such as rapid charge carrier recombination. Herein we present a triazine-heptazine copolymer synthesized by simple post-calcination of PCN in eutectic salts, that is, NaCl/KCl, to modulate the polymerization process and optimize the structure. The construction of an internal triazine-heptazine donor-acceptor (D-A) heterostructure was affirmed to significantly accelerate interface charge transfer (CT) and thus boost the photocatalytic activity (AQY=60 % at 420 nm). This study highlights the construction of intermolecular D-A copolymers in NaCl/KCl molten salts with higher melting points but in the absence of lithium to modulate the chemical structure and properties of PCN.

Abstract Tin‐based perovskites with excellent optoelectronic properties and suitable band gaps are promising candidates for the preparation of efficient lead‐free perovskite solar cells (PSCs). However, it is challenging to prepare highly stable and efficient tin‐based PSCs because Sn2+ in perovskites can be easily oxidized to Sn4+ upon air exposure. Here we report the fabrication of air‐stable FASnI3 solar cells by introducing hydroxybenzene sulfonic acid or its salt as an antioxidant additive into the perovskite precursor solution along with excess SnCl2. The interaction between the sulfonate group and the Sn2+ ion enables the in situ encapsulation of the perovskite grains with a SnCl2–additive complex layer, which results in greatly enhanced oxidation stability of the perovskite film. The corresponding PSCs are able to maintain 80 % of the efficiency over 500 h upon air exposure without encapsulation, which is over ten times longer than the best result reported previously. Our results suggest a possible strategy for the future design of efficient and stable tin‐based PSCs.

Pure organic, heavy-atom-free room-temperature phosphorescence (RTP) materials have attracted much attention and have potential applications in photoelectric and biochemical material fields owing to their rich excited state properties. They offer long luminescent lifetime, diversified design, and facile preparation. However, recent achievements of efficient phosphorescence under ambient conditions mainly focus on ordered crystal lattices or embedding into rigid matrices, which require strict growth conditions and have poor reproducibility. Herein, we developed a concise approach to give RTP with a decent quantum yield and ultralong phosphorescence lifetime in the amorphous state by radical binary copolymerization of acrylamide and different phosphors with oxygen-containing functional groups. The cross-linked hydrogen-bonding networks between the polymeric chains immobilize phosphors to suppress non-radiative transitions and provide a microenvironment to shield quenchers.

Abstract The search of new borates with improved functional properties has attracted considerable attention. Herein, a new polar fluorooxoborate, NaB4O6F (NBF) was prepared by high‐temperature solid‐state reaction. NBF belongs to the AB4O6F family (A=alkali metal or ammonium), a series of compounds that undergoes significant cation‐dependent structural changes. NBF is of particular interest owing to the special cation position. Temperature‐dependent ionic conductivity measurements show that NBF is a solid ionic conductor, and it has the lowest active energy of 32.5 kJ mol−1 of fluorooxoborates. NBF also shows a second‐harmonic generation (SHG) response of 0.9×KH2PO4 and 0.2×β‐BaB2O4, at 1064 and 532 nm, respectively, and it has a short UV cutoff edge below 180 nm. Based on bond valence (BV) concepts, symmetry analysis, and the first principles calculation, the unique [B4O6F]∞ layer can be regarded as the “multifunctional unit”, which is responsible for the observed properties of NBF.

Abstract Graphite carbon nitride (g‐C 3 N 4 ) is a promising candidate for photocatalytic hydrogen production, but only shows moderate activity owing to sluggish photocarrier transfer and insufficient light absorption. Herein, carbon quantum dots (CQDs) implanted in the surface plane of g‐C 3 N 4 nanotubes were synthesized by thermal polymerization of freeze‐dried urea and CQDs precursor. The CQD‐implanted g‐C 3 N 4 nanotubes (CCTs) could simultaneously facilitate photoelectron transport and suppress charge recombination through their specially coupled heterogeneous interface. The electronic structure and morphology were optimized in the CCTs, contributing to greater visible light absorption and a weakened barrier of the photocarrier transfer. As a result, the CCTs exhibited efficient photocatalytic performance under light irradiation with a high H 2 production rate of 3538.3 μmol g −1 h −1 and a notable quantum yield of 10.94 % at 420 nm.

Abstract Highly selective separation and/or purification of acetylene from various gas mixtures is a relevant and difficult challenge that currently requires costly and energy‐intensive chemisorption processes. Two ultramicroporous metal–organic framework physisorbents, NKMOF‐1‐M (M=Cu or Ni), offer high hydrolytic stability and benchmark selectivity towards acetylene versus several gases at ambient temperature. The performance of NKMOF‐1‐M is attributed to their exceptional acetylene binding affinity as revealed by modelling and several experimental studies: in situ single‐crystal X‐ray diffraction, FTIR, and gas mixture breakthrough tests. NKMOF‐1‐M exhibit better low‐pressure uptake than existing physisorbents and possesses the highest selectivities yet reported for C2H2/CO2 and C2H2/CH4. The performance of NKMOF‐1‐M is not driven by the same mechanism as current benchmark physisorbents that rely on pore walls lined by inorganic anions.

Oxidation chemistry using enzymes is approaching maturity and practical applicability in organic synthesis. Oxidoreductases (enzymes catalysing redox reactions) enable chemists to perform highly selective and efficient transformations ranging from simple alcohol oxidations to stereoselective halogenations of non-activated C-H bonds. For many of these reactions, no "classical" chemical counterpart is known. Hence oxidoreductases open up shorter synthesis routes based on a more direct access to the target products. The generally very mild reaction conditions may also reduce the environmental impact of biocatalytic reactions compared to classical counterparts. In this Review, we critically summarise the most important recent developments in the field of biocatalytic oxidation chemistry and identify the most pressing bottlenecks as well as promising solutions.

Photoredox catalysis comprising homogeneous transition-metal-based systems, organic dyes, and semiconductors, has become a universal tool to catalyze a wide variety of chemical reactions with high selectivity and under mild conditions using visible light irradiation. This Minireview summarizes recent progress in photoredox catalysis mediated by heterogeneous carbon nitride materials such as mesoporous graphitic carbon nitride (mpg-CN), polymeric carbon nitride, and potassium poly(heptazine imides) (K-PHI). Because of the high thermal, chemical, and photostability of these materials, as well as favorable conduction and valence band positions, carbon nitrides expand the reaction range of photocatalysis to many novel reactions, such as photocatalytic activation of elemental sulfur to furnish a convenient chemical route to organosulfur compounds.

Abstract Transition‐metal sulfides (TMSs) have emerged as important candidates for oxygen evolution reaction (OER) electrocatalysts. Now a hybrid nanostructure has been decorated with CeO x nanoparticles on the surface of ZIF‐67‐derived hollow CoS through in situ generation. Proper control of the amount of CeO x on the surface of CoS can achieve precise tuning of Co 2+ /Co 3+ ratio, especially for the induced defects, further boosting the OER activity. Meanwhile, the formation of protective CeO x thin layer effectively inhibits the corrosion by losing cobalt ion species from the active surface into the solution. It is thus a rare example of a hybrid hetero‐structural electrocatalyst with CeO x NPs to improve the performance of the hollow TMS nanocage.

Abstract Low‐cost, efficient bifunctional electrocatalysts are needed to mediate the oxygen reduction and oxygen evolution reactions (ORR/OER) in Zn–air batteries. Such catalysts should offer binary active sites and an ability to transfer oxygen‐based species and electrons. A 3D catalyst, composed of nanoparticles of CoFe alloy embedded in N‐doped carbon nanotubes tangled with reduced graphene oxide, was developed, which presents appreciable ORR/OER activity when applied in a Zn–air battery. A high open‐circuit voltage of 1.43 V, a stable discharge voltage of 1.22 V, a high energy efficiency of 60.1 %, and excellent stability after 1 600 cycles at 10 mA cm−2 are demonstrated. An all‐solid‐state battery had an outstanding lifetime and high cell efficiency even upon bending. In situ X‐ray absorption spectroscopy revealed that OOH* and O* intermediates induce variations in the Fe−Fe and Co−Co bond lengths, respectively, suggesting that Fe and Co species are crucial to the ORR/OER processes.

Phenolic materials have long been known for their use in inks, wood coatings, and leather tanning. However, there has recently been a renewed interest in engineering advanced materials from phenolic building blocks. The intrinsic properties of phenolic compounds, such as metal chelation, hydrogen bonding, pH responsiveness, redox potentials, radical scavenging, polymerization, and light absorbance, have made them a distinct class of structural motifs for the synthesis of functional materials. Materials prepared from phenolic compounds often retain many of these useful properties with synergistic effects in applications ranging from catalysis to biomedicine. This Review provides an overview of the diverse functional materials that can be prepared from natural and synthetic phenolic building blocks, as well as their applications.

Abstract Potassium‐ion batteries (KIBs) are plagued by a lack of materials for reversible accommodation of the large‐sized K+ ion. Herein we present, the Bi anode in combination with the dimethoxyethane‐(DME) based electrolyte to deliver a remarkable capacity of ca. 400 mAh g−1 and long cycle stability with three distinct two‐phase reactions of Bi↔ KBi2↔K3Bi2↔K3Bi. These are ascribed to the gradually developed three‐dimensional (3D) porous networks of Bi, which realizes fast kinetics and tolerance of its volume change during potassiation and depotassiation. The porosity is linked to the unprecedented movement of the surface Bi atoms interacting with DME molecules, as suggested by DFT calculations. A full KIB of Bi//DME‐based electrolyte//Prussian blue of K0.72Fe[Fe(CN)6] is demonstrated to present large energy density of 108.1 Wh kg−1 with average discharge voltage of 2.8 V and capacity retention of 86.5 % after 350 cycles.

Abstract Aromatic‐imide‐based thermally activated delayed fluorescent (TADF) enantiomers, (+)‐( S , S )‐ CAI‐Cz and (−)‐( R , R )‐ CAI‐Cz , were efficiently synthesized by introducing a chiral 1,2‐diaminocyclohexane to the achiral TADF unit. The TADF enantiomers exhibited high PLQYs of up to 98 %, small Δ E ST values of 0.06 eV, as well as obvious temperature‐dependent transient PL spectra, thus demonstrating their excellent TADF properties. Moreover, the TADF enantiomers showed mirror‐image CD and CPL activities. Notably, the CP‐OLEDs with CPEL properties based on the TADF enantiomers not only achieved high EQE values of up to 19.7 and 19.8 %, but also displayed opposite CPEL signals with g EL values of −1.7×10 −3 and 2.3×10 −3 , which represents the first CP‐OLEDs, based on the enantiomerically pure TADF materials, having both high efficiencies and intense CPEL.

Abstract Single atoms immobilized on metal–organic frameworks (MOFs) with unique nanostructures have drawn tremendous attention in the application of catalysis but remain a great challenge. Various single noble‐metal atoms have now been successfully anchored on the well‐defined anchoring sites of the zirconium porphyrin MOF hollow nanotubes, which are probed by aberration‐corrected scanning transmission electron microscopy and synchrotron‐radiation‐based X‐ray absorption fine‐structure spectroscopy. Owing to the hollow structure and excellent photoelectrochemical performance, the HNTM‐Ir/Pt exhibits outstanding catalytic activity in the visible‐light photocatalytic H 2 evolution via water splitting. The single atom immobilized on MOFs with hollow structures are expected to pave the way to expand the potential applications of MOFs.

This review summarizes recent advances in the chemistry of curved aromatic molecules. By focusing on the key accomplishments of the last decade, we provide a general overview of synthetic methods capable of efficient induction of internal strain in π-conjugated frameworks. The review is structured according to the topology change involved in the strain-inducing reaction step (cyclizations, eliminations, ring expansions and contractions), and highlights the striking diversity of structures achievable with modern synthetic methodology.

Tough hydrogels, polymeric network structures with excellent mechanical properties (such as high stretchability and toughness), are emerging soft materials. Despite their remarkably mechanical features, tough hydrogels exhibit two flaws (freezing around the icing temperatures of water and drying under arid conditions). Inspired by cryoprotectants (CPAs) used in the inhibition of the icing of water in biological samples, a versatile and straightforward method is reported to fabricate extreme anti-freezing, non-drying CPA-based organohydrogels with long-term stability by partially displacing water molecules within the pre-fabricated hydrogels. CPA-based Ca-alginate/polyacrylamide (PAAm) tough hydrogels were successfully fabricated with glycerol, glycol, and sorbitol. The CPA-based organohydrogels remain unfrozen and mechanically flexible even up to -70 °C and are stable under ambient conditions or even vacuum.

Flexible perovskite solar cells have attracted widespread research effort because of their potential in portable electronics. The efficiency has exceeded 18 % owing to the high-quality perovskite film achieved by various low-temperature fabrication methods and matching of the interface and electrode materials. This Review focuses on recent progress in flexible perovskite solar cells concerning low-temperature fabrication methods to improve the properties of perovskite films, such as full coverage, uniform morphology, and good crystallinity; demonstrated interface layers used in flexible perovskite solar cells, considering key figures-of-merit such as high transmittance, high carrier mobility, suitable band gap, and easy fabrication via low-temperature methods; flexible transparent electrode materials developed to enhance the mechanical stability of the devices; mechanical and long-term environmental stability; an outlook of flexible perovskite solar cells in portable electronic devices; and perspectives of commercialization for flexible perovskite solar cells based on cost.

Discovery of elusive K4O6 an endothermic mixed peroxide–superoxide compound: In the Communication on page 149, M. Jansen et al. report on the synthesis of K4O6 that owes its stability to the configurational entropy of polarons, and thus exists only above a distinct temperature threshold. The puzzling speed at which the all-solid-state reactions of formation and decomposition proceed, as a function of temperature, are illustratively documented by a real-time video.

Suppressing the linker mobility and tuning the aperture size of a MOF membrane is important to achieve promising gas sieving performance. In their communication on page 327 ff., Y. Wei, J. Caro, H. Wang et al. proposed a double strategy of “stiffening and narrowing” to prepare a roughly 500 nm thin hybrid mixed-linker ZIF-7x-8 membrane with suppressed flexibility and narrowed window aperture through a fast current-driven synthesis (FCDS). The membrane shows significantly sharpened CO2/CH4 sieving with a separation factor up to 25.

Abstract For electrocatalytic water splitting, the sluggish anodic oxygen evolution reaction (OER) restricts the cathodic hydrogen evolution reaction (HER). Therefore, developing an alternative anodic reaction with accelerating kinetics to produce value‐added chemicals, especially coupled with HER, is of great importance. Now, a thermodynamically more favorable primary amine (−CH 2 −NH 2 ) electrooxidation catalyzed by NiSe nanorod arrays in water is reported to replace OER for enhancing HER. The increased H 2 production can be obtained at cathode; meanwhile, a variety of aromatic and aliphatic primary amines are selectively electrooxidized to nitriles with good yields at the anode. Mechanistic investigations suggest that Ni II /Ni III may serve as the redox active species for the primary amines transformation. Hydrophobic nitrile products can readily escape from aqueous electrolyte/electrode interface, avoiding the deactivation of the catalyst and thus contributing to continuous gram‐scale synthesis.

Abstract The electrochemical reduction reaction of carbon dioxide (CO2RR) to carbon monoxide (CO) is the basis for the further synthesis of more complex carbon‐based fuels or attractive feedstock. Single‐atom catalysts have unique electronic and geometric structures with respect to their bulk counterparts, thus exhibiting unexpected catalytic activities. A nitrogen‐anchored Zn single‐atom catalyst is presented for CO formation from CO2RR with high catalytic activity (onset overpotential down to 24 mV), high selectivity (Faradaic efficiency for CO (FE CO ) up to 95 % at −0.43 V), remarkable durability (>75 h without decay of FE CO ), and large turnover frequency (TOF, up to 9969 h −1 ). Further experimental and DFT results indicate that the four‐nitrogen‐anchored Zn single atom (Zn‐N 4 ) is the main active site for CO2RR with low free energy barrier for the formation of *COOH as the rate‐limiting step.

Abstract A hundred years on, the energy‐intensive Haber–Bosch process continues to turn the N 2 in air into fertilizer, nourishing billions of people while causing pollution and greenhouse gas emissions. The urgency of mitigating climate change motivates society to progress toward a more sustainable method for fixing N 2 that is based on clean energy. Surface oxygen vacancies (surface O vac ) hold great potential for N 2 adsorption and activation, but introducing O vac on the very surface without affecting bulk properties remains a great challenge. Fine tuning of the surface O vac by atomic layer deposition is described, forming a thin amorphous TiO 2 layer on plasmon‐enhanced rutile TiO 2 /Au nanorods. Surface O vac in the outer amorphous TiO 2 thin layer promote the adsorption and activation of N 2 , which facilitates N 2 reduction to ammonia by excited electrons from ultraviolet‐light‐driven TiO 2 and visible‐light‐driven Au surface plasmons. The findings offer a new approach to N 2 photofixation under ambient conditions (that is, room temperature and atmospheric pressure).

Abstract Until now, MXenes could only be produced from MAX phases containing aluminum, such as Ti3AlC2. Here, we report on the synthesis of Ti3C2 (MXene) through selective etching of silicon from titanium silicon carbide—the most common MAX phase. Liters of colloidal solutions of delaminated Ti3SiC2‐derived MXene (0.5–1.3 mg mL−1) were produced and processed into flexible and electrically conductive films, which show higher oxidation resistance than MXene synthesized from Ti3AlC2. This new synthesis method greatly widens the range of precursors for MXene synthesis.

Abstract Energy efficient buildings require materials with a low thermal conductivity and a high fire resistance. Traditional organic insulation materials are limited by their poor fire resistance and inorganic insulation materials are either brittle or display a high thermal conductivity. Herein we report a mechanically resilient organic/inorganic composite aerogel with a thermal conductivity significantly lower than expanded polystyrene and excellent fire resistance. Co‐polymerization and nanoscale phase separation of the phenol‐formaldehyde‐resin (PFR) and silica generate a binary network with domain sizes below 20 nm. The PFR/SiO 2 aerogel can resist a high‐temperature flame without disintegration and prevents the temperature on the non‐exposed side from increasing above the temperature critical for the collapse of reinforced concrete structures.

Despite wide applications of bimetallic electrocatalysis in oxygen evolution reaction (OER) owing to their superior performance, the origin of the improved performance remains elusive. The underlying mechanism was explored by designing and synthesizing a series of stable metal-organic frameworks (MOFs: NNU-21-24) based on trinuclear metal carboxylate clusters and tridentate carboxylate ligands. Among the examined stable MOFs, NNU-23 exhibits the best OER performance; particularly, compared with monometallic MOFs, all the bimetallic MOFs display improved OER activity. DFT calculations and experimental results demonstrate that introduction of the second metal atom can improve the activity of the original atom. The proposed model of bimetallic electrocatalysts affecting their OER performance can facilitate design of efficient bimetallic catalysts for energy storage and conversion, and investigation of the related catalytic mechanisms.

Abstract Solar‐driven reduction of CO2, which converts inexhaustible solar energy into value‐added fuels, has been recognized as a promising sustainable energy conversion technology. However, the overall conversion efficiency is significantly limited by the inefficient charge separation and sluggish interfacial reaction dynamics, which resulted from a lack of sufficient active sites. Herein, Bi12O17Cl2 superfine nanotubes with a bilayer thickness of the tube wall are designed to achieve structural distortion for the creation of surface oxygen defects, thus accelerating the carrier migration and facilitating CO2 activation. Without cocatalyst and sacrificing reagent, Bi12O17Cl2 nanotubes deliver high selectivity CO evolution rate of 48.6 μmol g−1 h−1 in water (16.8 times than of bulk Bi12O17Cl2), while maintaining stability even after 12 h of testing. This paves the way to design efficient photocatalysts with collaborative optimizing charge separation and CO2 activation towards CO2 photoreduction.

Abstract Water electrolysis is a promising source of hydrogen; however, technological challenges remain. Intensive efforts have focused on developing highly efficient and earth‐abundant electrocatalysts for water splitting. An effective strategy is proposed, using a bifunctional tubular cobalt perselenide nanosheet electrode, in which the sluggish oxygen evolution reaction is substituted with anodic hydrazine oxidation so as to assist energy‐efficient hydrogen production. Specifically, this electrode produces a current density of 10 mA cm −2 at −84 mV for hydrogen evolution and −17 mV for hydrazine oxidation in 1.0 m KOH and 0.5 m hydrazine electrolyte. An ultralow cell voltage of only 164 mV is required to generate a current density of 10 mA cm −2 for 14 hours of stable water electrolysis.

Eosin Y, a well-known economical alternative to metal catalysts in visible-light-driven single-electron transfer-based organic transformations, can behave as an effective direct hydrogen-atom transfer catalyst for C-H activation. Using the alkylation of C-H bonds with electron-deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y-based photocatalytic hydrogen-atom transfer strategy is promising for diverse functionalization of a wide range of native C-H bonds in a green and sustainable manner.

Over the past few years, non-fullerene organic solar cells have been a focus of research and their power conversion efficiencies have been improved dramatically from about 6 % to over 14 %. In addition to innovations in non-fullerene acceptors, the ongoing development of polymer donors has contributed significantly to the rapid progress of non-fullerene organic solar cell performance. This Minireview highlights the polymer donors that enable high-performance non-fullerene organic solar cells. We show the impressive photovoltaic devices results achieved by some of important classes of conjugated polymer systems in non-fullerene organic solar cells. We discuss the molecular design strategies as far as developing matching polymer donors for non-fullerene acceptors. We conclude with a brief summary and outlook for advances in donor polymers required for commercialization.

Abstract Electrocatalytic CO2 reduction to CO emerges as a potential route of utilizing emitted CO2. Metal‐N‐C hybrid structures have shown unique activities, however, the active centers and reaction mechanisms remain unclear because of the ambiguity in true atomic structures for the prepared catalysts. Herein, combining density‐functional theory calculations and experimental studies, the reaction mechanisms for well‐defined metal–N4 sites were explored using metal phthalocyanines as model catalysts. The theoretical calculations reveal that cobalt phthalocyanine exhibits the optimum activity for CO2 reduction to CO because of the moderate *CO binding energy at the Co site, which accommodates the *COOH formation and the *CO desorption. It is further confirmed by experimental studies, where cobalt phthalocyanine delivers the best performance, with a maximal CO Faradaic efficiency reaching 99 %, and maintains stable performance for over 60 hours.

Abstract In situ and operando spectroscopic and microscopic methods were used to gain insight into the correlation between the structure, chemical state, and reactivity of size‐ and shape‐controlled ligand‐free Cu nanocubes during CO2 electroreduction (CO2RR). Dynamic changes in the morphology and composition of Cu cubes supported on carbon were monitored under potential control through electrochemical atomic force microscopy, X‐ray absorption fine‐structure spectroscopy and X‐ray photoelectron spectroscopy. Under reaction conditions, the roughening of the nanocube surface, disappearance of the (100) facets, formation of pores, loss of Cu and reduction of CuOx species observed were found to lead to a suppression of the selectivity for multi‐carbon products (i.e. C2H4 and ethanol) versus CH4. A comparison with Cu cubes supported on Cu foils revealed an enhanced morphological stability and persistence of CuI species under CO2RR in the former samples. Both factors are held responsible for the higher C2/C1 product ratio observed for the Cu cubes/Cu as compared to Cu cubes/C. Our…