Search

In oxygen reduction reaction, Pt/C catalysts are prone to carbon corrosion, resulting in reduced activity. The use of non-carbon inorganic supports not only improves corrosion resistance, but also provides synergetic effects to increase activity and stability.

A rock-salt-structured Li-conducting high entropy oxide was prepared and utilized as an active filler in a polyethylene oxide (PEO)-based solid-state composite electrolyte. X-ray diffraction and high-resolution transmission electron microscopy were adopted to analyze the crystal structure of the high entropy oxide containing 20% of Li ions (HL20). The HL20 was crystallized in the

Rieske-type non-heme iron oxygenases/oxidases catalyze a wide range of transformations. Their applications in bioremediation or biocatalysis face two key barriers: the need of expensive NAD(P)H as a reductant and a proper reductase to mediate the electron transfer from NAD(P)H to the oxygenases. To bypass the need of both the reductase and NAD(P)H, using Rieske-type oxygenase (Stc2) catalyzed oxidative demethylation as the model system, we report Stc2 photocatalysis using eosin Y/sulfite as the photosensitizer/sacrificial reagent pair. In a flow-chemistry setting to separate the photo-reduction half-reaction and oxidation half-reaction, Stc2 photo-biocatalysis outperforms the Stc2-NAD(P)H-reductase (GbcB) system. In addition, in a few other selected Rieske enzymes (NdmA, CntA, and GbcA), and a flavin-dependent enzyme (iodotyrosine deiodinase, IYD), the eosin Y/sodium sulfite photo-reduction pair could also serve as the NAD(P)H-reductase surrogate to support catalysis, which implies the potential applicability of this photo-reduction system to other redox enzymes.

The functions of interfacial synergy in heterojunction catalysts are diverse and powerful, providing a route to solve many difficulties in energy conversion and organic synthesis. Among heterojunction-based catalysts, the Mott-Schottky catalysts composed of a metal-semiconductor heterojunction with predictable and designable interfacial synergy are rising stars of next-generation catalysts. We review the concept of Mott-Schottky catalysts and discuss their applications in various realms of catalysis. In particular, the design of a Mott-Schottky catalyst provides a feasible strategy to boost energy conversion and chemical synthesis processes, even allowing realization of novel catalytic functions such as enhanced redox activity, Lewis acid-base pairs, and electron donor-acceptor couples for dealing with the current problems in catalysis for energy conversion and storage. This review focuses on the synthesis, assembly, and characterization of Schottky heterojunctions for photocatalysis, electrocatalysis, and organic synthesis. The proposed design principles, including the importance of constructing stable and clean interfaces, tuning work function differences, and preparing exposable interfacial structures for designing electronic interfaces, will provide a reference for the development of all heterojunction-type catalysts, electrodes, energy conversion/storage devices, and even super absorbers, which are currently topics of interest in fields such as electrocatalysis, fuel cells, CO

Currently, converting hydrocarbons into high-value-added products through photocatalytic selective activation under mild conditions is attractive and challenging, motivating research efforts to explore inexpensive and efficient photocatalysts. Here, we report a donor-acceptor polymer with tunable valence band to trigger direct photocatalytic C-H bond activation for selective oxidation, halogenation and coupling reactions using visible light and air without the assistance of any sacrificial additives. Apart from the fast charge separation driven by donor-acceptor pairs, both experimental and theoretical results have demonstrated that the downshifted valence band of the polymer photocatalyst dominated the enhanced oxidation power to accelerate C-H bond activation. resulting in the best-in-class catalytic performance of paraxylene oxidation with high aldehyde selectivity (> 99%), outperforming the state-of-the-art metal-free homogeneous catalysts in the literature by a factor of 4.

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted extensive attention due to their low cost and high safety. However, the critical issues of dendrite growth and side reactions on the Zn metal anode hinder the commercialization of ZIBs. Herein, we demonstrated that the formation of Zn

An unstable solid electrolyte interphase (SEI) and chaotic lithium ion flux are key impediments to commercial high-energy-density lithium batteries because of the uncontrolled growth of rigid lithium dendrites, which would pierce through the conventional polypropylene (PP) separator, causing short circuit and safety issues. Herein, the homogenization of lithium ion flux and the generation of stable SEI layers on lithium anodes were achieved via coating a fluorine-functionalized Ti3C2 (F-Ti3C2) nanosheets on PP separator (F-Ti3C2@PP). F-Ti3C2 nanosheets provide abundant ions pathways to homogeneously manipulate lithium ion flux and increase the Young’s modulus and electrolyte wettability of the separators. In addition, F species derived from the F-Ti3C2 nanosheets would promote the formation of LiF-rich SEI film. The synergistic effect contribute to the uniform lithium deposition. Symmetric Li|Li, asymmetric Li|Cu and full Li|LiFePO4 cells incorporated with the modified separators exhibit improved electrochemical performance even under lean electrolyte conditions. This work provides a feasible strategy to improve the performance of lithium batteries through both fluoridized SEI formation and lithium ion flux manipulation.

A multistep electron transfer process is realized over C12A7:e− electride composite material. The graphene promotes electron transfer from C12A7:e− through surface Pd to the aryl halide substrates, affording a series of cross-coupling reactions.

Platinum (Pt) is the most effective bench-marked catalyst for producing renewable and clean hydrogen energy by electrochemical water splitting. There is demand for high HER catalytic activity to achieve efficient utilization and minimize the loading of Pt in catalysts. In this work, we significantly boost the HER mass activity of Pt nanoparticles in Pt x /Co to 8.3 times higher than that of commercial Pt/C by using Co/NC heterojunctions as a heterogeneous version of electron donors. The highly coupled interfaces between Co/NC and Pt metal enrich the electron density of Pt nanoparticles to facilitate the adsorption of H + , the dissociation of Pt-H bonds and H 2 release, giving the lowest HER overpotential of 6.9 mV vs. RHE at 10 mA/cm 2 in acid among reported HER electrocatalysts. Given the easy scale-up synthesis due to the stabilization of ultrafine Pt nanoparticles by Co/NC solid ligands, Pt x /Co can even be a promising substitute for commercial Pt/C for practical applications.

NOx- reduction acts a pivotal part in sustaining globally balanced nitrogen cycle and restoring ecological environment, ammonia (NH3) is an excellent energy carrier and the most valuable product among all the products of NOx- reduction reaction, the selectivity of which is far from satisfaction due to the intrinsic complexity of multiple-electron NOx--to-NH3 process. Here, we utilize the Schottky barrier-induced surface electric field, by the construction of high density of electron-deficient Ni nanoparticles inside nitrogen-rich carbons, to facilitate the enrichment and fixation of all NO x - anions on the electrode surface, including NO 3 - and NO 2 - , and thus ensure the final selectivity to NH 3 . Both theoretical and experimental results demonstrate that NO x - anions were continuously captured by the electrode with largely enhanced surface electric field, providing excellent Faradaic efficiency of 99 % from both electrocatalytic NO 3 - and NO 2 - reduction. Remarkably, the NH 3 yield rate could reach the maximum of 25.1 mg h -1 cm -2 in electrocatalytic NO 2 - reduction reaction, outperforming the maximum in the literature by a factor of 6.3 in neutral solution. With the universality of our electrocatalyst, all sorts of available electrolytes containing NO x - pollutants, including seawater or waste water, could be directly used for ammonia production in potential through sustainable electrochemical technology.

Li-CO2 batteries are regarded as next-generation high-energy-density electrochemical devices. However, the greatest challenge arises from the formation of the discharge product, Li2 CO3 , which would accumulate and deactivate heterogenous catalysts to cause huge polarization. Herein, Ru(bpy)3 Cl2 was employed as a solution-phase catalyst for Li-CO2 batteries and proved to be the most effective one screened so far. Spectroscopy and electrochemical analyses elucidate that the RuII center could interact with both CO2 and amorphous Li2 C2 O4 intermediate, thus promoting electroreduction process and delaying carbonate transformation. As a result, the charge potential is reduced to 3.86 V and over 60 discharge/charge cycles are achieved with a fixed capacity of 1000 mAh g-1 at a current density of 300 mA g-1 . Our work provides a new avenue to improve the electrochemical performance of Li-CO2 batteries with efficient mobile catalysts.

Organic synthesis, as a kind of important chemical process closely related to the industry production, environment and energy of human society, is in urgent need of safe, clean, and environmentally benign reagents and routes to realize sustainable chemistry. In last decade, heterogeneous semiconductor nanomaterials catalyzed organic system has long been a promising technology for advanced chemicals manufacturing due to their advantages of durability, low‐pollution, and high‐scalability. To overcome the limitation posed by unsatisfied reactivity, compositing active components with semiconductor‐host that can endow highly interacted nanohybrids with enhancement of surface chemical properties has proved to be an indispensable technique for achieving high‐efficiency performance. This review summarizes recent progress on typical semiconductor‐based composites including traditional metal oxide, polymeric carbon nitride, N‐doped carbon and metal‐organic framework (MOFs) applied in organic synthesis. We focus on the compositing promotion mechanism based on semiconductor‐host composites and structure‐performance relationship in catalytic process. This review is anticipated to provide sparking inspiration for designing next‐generation heterogeneous nanocatalyts towards practical application.

Metallic zinc is widely considered as the most promising anode candidate for next-generation rechargeable aqueous batteries owing to its high volumetric capacity and intrinsic safety. However, the inferior reversibility caused by uncontrolled dendrite growth and parasitic side reactions severely impedes the commercial application of rechargeable Zn-based batteries. Herein, a fast Zn-ion conductor, Zn-intercalated montmorillonite (Zn-Mont), is designed as an artificial solid/electrolyte interphase (SEI) film to tune the transfer and deposition behavior of Zn2+ ions on the surface of Zn anodes. Benefiting from the low Zn-ion migration energy barrier and Zn ion-selective pathway, the Zn-Mont coating could guarantee a homogeneous Zn-ion flux, and fast Zn2+ transfer kinetics, and avoid the ion/electron accumulation at the interface of the anode, thereby suppressing the growth of Zn dendrites. In addition, the Zn-Mont layer can prevent direct contact of the Zn metal with bulk electrolyte, alleviating the water/O2-induced side reactions. Consequently, high reversibility (coulombic efficiency > 99.6%), long-time stability (over 1000 cycles), and ultralow polarization (overpotential ≈ 28 mV) are achieved. When coupled with the MnO2 cathode, Zn@Zn-Mont||MnO2 full cells deliver outstanding cycling stability with 85.4% capacity retention (calculated based on the specific capacity of the 5th cycle) after 1000 cycles at 2C.

The conversion and utilization of CO2 is a promising approach to build a sustainable future which not only reduces emissions from sources but also converts CO2 into high value-added products. During this process, the selective adsorption of CO2 molecules and the subsequent activation of CO bonds are two key steps, where the catalyst plays an irreplaceable role as the “accelerator” to regulate the reaction pathway and improve the reaction activity and selectivity. With the continuous development of green chemistry, the main drawbacks in homogeneous catalysts such as poor reusability and low hydrothermal stability have been overcome, and the application potential of heterogeneous nano-catalytic materials in CO2 chemical fixation has been explored, providing the possibility for large-scale industrial use. This review focuses on nanocarbons and related hybrids as catalytic materials in CO2 chemical fixation because these catalysts are widely used and easy to operate. We also summarize strategies to construct effective catalytic sites and discuss roles that nanocarbons play in catalytic systems.

Organic compounds with high theoretical capacity, tunable redox potentials and rich structural chemistry are considered as promising electrode materials for sodium-ion batteries (SIBs). However, organic electrode materials suffer from low electronic conductivity and low structural stability, hindering their practical applications. Thiophene compounds have been well considered in the design of photoelectric materials with improved charge transfer properties. It is envisaged that electron-transfer capability is also essential in addressing the issues of organic electrode materials for SIBs. Herein, sodium thieno[3,2-b]thiophene-2,5-dicarboxylate (STTDC), an organic compound with high electron transfer capability is designed and synthesized. When employed as an electrode material for SIBs, remarkably high electrochemical performance, including large reversible capacity, high rate capability and excellent stability was achieved. A large specific discharge capacity of 430 mA h g−1 is delivered at a current density of 50 mA g−1. A high reversible capacity of approximately 288 mA h g−1 is retained after 4000 cycles at a high current density of 2.0 A g−1. The present work sheds new light on the design of high-performance organic electrode materials.

Stille cross-coupling reactions catalysed by an ideal catalyst combining the high activity of homogeneous catalysts and the reusability of heterogeneous catalysts are of great interest for C–C bond formation, which is a widely used reaction in fine chemistry. Despite great effort to increase the utilization ratio of surface metal atoms, the activity of heterogeneous catalysts under mild conditions remains unsatisfactory. Herein, we design a proof-of-concept strategy to trigger the room-temperature activity of heterogeneous Au catalysts by decreasing the electron density at the interface of a rationally designed Schottky heterojunction of Au metals and boron-doped carbons. The electron-deficient Au nanoparticles formed as a result of the rectifying contact with boron-doped carbons facilitate the autocleavage of C–Br bonds for highly efficient C–C coupling reactions of alkylbromides and allylstannanes with a TOF value of 5199 h−1 at room temperature, surpassing that of the state-of-the-art homogeneous catalyst.

A Sr2+-doping strategy is developed to engineer rich oxygen vacancies in porous titania for boosting visible-light-driven photocatalytic activity. The incorporation of strontium, with a larger atom radius than titanium, leads to the release of a lattice oxygen atom in the titania, causing the generation of an oxygen vacancy. The optimal Sr2+-doped titania sample with rich oxygen vacancies achieves a photocatalytic hydrogen production rate as high as 1092 μmol h-1 g-1, which is 4 and 16 times higher than the unmodified titania with less oxygen vacancies and the bench-marked P25, respectively.

Transition metal-based catalysts usually suffer from poor coke resistance during the dehydrogenation processes of hydrocarbon compounds in gas–solid heterogeneous systems, including methanol dehydr...

Aprotic Li-O2 batteries with high theoretical energy density are regarded as promising next-generation energy storage devices. However, the accumulation of discharge products (Li2O2) duiring the discharge/charge processes would lead to high overpotential, low round-trip efficiency and poor cycling stability of the batteries. Soluble redox mediators (RMs) have been proved to be efficient in promoting the oxidation of Li2O2 particles. However, the self-discharge of the electrochemically oxidized RMs (RMsox) on the surface of Li metal would accelerate the formation of lithium dendrites. In this work, nitrogenous radicals, 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH), is designed and employed as a RMs to lower the overpotential of Li–O2 batteries. Moreover, the self-discharge of the oxidized DPPH on the surface of Li metal and the formation of lithium dendrites are successfully suppressed by the formation of graphene/luteolin protective layer on Li metal. Consequently, an ultrastable cycle stability (>150 cycles) is achieved with DPPH and the stable graphene/luteolin protective layer for the Li metal anodes. These synergistic effect of RMs and stable Li protective layer may inspire the development of sustainable and durable Li–O2 batteries.

Heterogeneous catalysts have been developed for C-C coupling reactions, but stand low activity and always proceed under harsh conditions. Photocatalytic Stille cross-coupling reaction as a green catalytic method for C-C bond formation is of great interest for a wide range of scientists but still lacks stable and highly efficient catalysts. Herein, we have designed an Au nanoparticle-graphitic carbon nitride heterojunction as an outstanding photo-catalyst for artificial photosynthesis in Stille cross-coupling reaction. The interface effect between metal and semiconductor makes electron rectify and prevents the recombination of electron-hole pairs. Moreover, the efficiency of Au nanoparticle catalysts could be adjusted by gold contents. Thus the turnover frequency(TOF) value reached the highest level of 788 h−1 over the optimal heterojunction catalyst. Most importantly, the C-C bond formation reaction has been proved to be carried out well under visible light irradiation, indicating the low-cost organic synthesis process. Further analysis confirmed the stability and general application of our heterogeneous Au nano-heterojunction catalyst.

Ergothioneine, a natural longevity vitamin and antioxidant, is a thiol-histidine derivative. Recently, two types of biosynthetic pathways were reported. In the aerobic ergothioneine biosynthesis, a non-heme iron enzyme incorporates a sulfoxide to an sp(2) C-H bond in trimethyl-histidine (hercynine) through oxidation reactions. In contrast, in the anaerobic ergothioneine biosynthetic pathway in a green sulfur bacterium, Chlorobium limicola, a rhodanese domain containing protein (EanB) directly replaces this unreactive hercynine C-H bond with a C-S bond. Herein, we demonstrate that polysulfide (HSS(n)SR) is the direct sulfur-source in EanB-catalysis. After identifying EanB’s substrates, X-ray crystallography of several intermediate states along with mass spectrometry results provide additional mechanistic details for this reaction. Further, quantum mechanics/molecular mechanics (QM/MM) calculations reveal that protonation of N(π) of hercynine by Tyr353 with the assistance of Thr414 is a key activation step for the hercynine sp(2) C-H bond in this trans-sulfuration reaction.

The rational design of highly active and stable atomically dispersed M-X4 (M = Fe, Co, Ni, etc., X = C, N) -based catalysts holds promises for wide application in almost all realms of catalysis. Despite great effort in the construction of specific M-X4 centers, the possible effect of non-coordinated heteroatoms on the catalytic activity of metal centers has been rarely explored. Herein, we develop a new type of M-X4 catalyst composed of Fe-N4 centers and non-coordinated B heteroatoms (FeNC+B) and find the key role of non-coordinated B adjacent to Fe-N4 centers in tailoring their electron density and final catalytic selectivity. The experimental and theoretical results demonstrated that non-coordinated boron atoms could decrease the electron density of Fe-N4 centers to a suitable level and thus boost the selective production of nitriles from amine oxidation by depressing the formation of imines due to the flattened energy barrier of the reversible conversion of imines back to amines. As a reusable heterocatalyst, the state-of-the-art FeNC+B catalyst provides a turn-over frequency (TOF) value of 21.6 molbenzonitrile·molFe−1·h−1 (100 °C), outpacing that of bench-marked nonnoble-metal-based homogeneous catalyst by a factor of 3.4.

The direct hydrogenation of CO2 using H2 gas is a one-stone-two-birds route to produce highly value-added hydrocarbon compounds and to lower the CO2 level in the atmosphere. However, the transformation of CO2 and H2 into hydrocarbons has always been a great challenge while ensuring both the activity and selectivity over abundant-element-based nanocatalysts. In this work, we designed a Schottky heterojunction composed of electron-rich MoC nanoparticles embedded inside an optimized nitrogen-doped carbon support (MoC@NC) as the first example of noble-metal-free heterogeneous catalysts to boost the activity of and specific selectivity for CO2 hydrogenation to formic acid (FA) in liquid phase under mild conditions (2 MPa pressure and 70 °C). The MoC@NC catalyst with a high turnover frequency (TOF) of 8.20 molFA molMoC−1 h−1 at 140 °C and an excellent reusability are more favorable for real applications.

Inferior charge transport in discharge products is one of the main factors restricting the technological potential of lithium-oxygen batteries. Here, we propose a strategy to enhance charge transport in discharge products by surface engineering of cathode catalysts with donor and acceptor sites to improve solid-solid interfacial electron transfer properties between catalysts and discharge products. Free-standing layered double oxides loaded with pyrolyzed sodium poly(aminobenzenesulfonate)-derived sulfur-doped carbon nanosheets and carbon nanosheets with sulfoxide groups are synthesized and utilized to investigate donor and acceptor sites effect on the performance of lithium-oxygen batteries. The free-standing cathode with hybrid donor and acceptor sites is capable of operation in oxygen with distinct (dis)charge plateau and superior cycling stability (over 60 cycles at a fixed capacity of 0.53 mAh cm−2). The superior properties are attributed to the enhanced charge transport in lithium peroxide by the formation of hole polarons/Li+ vacancies on acceptor sites and electron polarons/disordered lithium peroxide phase on donor sites. This work provides a promising route to enhance defective charge transport in discharge products by optimization of donor and acceptor sites on cathode catalysts for high-performance lithium-oxygen batteries.

Metal selenides as anode materials for sodium-ion batteries have attracted considerable attention owing to their high theoretical specific capacities and variable composition and structures. However, the achievement of long cycle life and superior rate performance is challenging for these selenide materials due to the volume variation upon cycling. Herein, a composite composed of a new binary-metal selenide[Cu2SnSe3(CSS)] and carbon nanotubes(CNTs) was constructed via a hydrothermal process followed by calcination at 600 °C. Benefited from the unique structure of binary-metal selenide and the conductive network of CNTs, the Cu2SnSe3/carbon nanotubes(CSS/CNT) composite exhibits excellent electrochemical performance when used as an anode material for sodium-ion batteries. A reversible specific capacity of 399 mA·h/g can be maintained at a current density of 100 mA/g even after 100 cycles. This work provides a promising strategy for rational design of binary-metal selenides upon delicate crystal phase control as electrode materials.