The S‐scheme heterojunctions have great potential for photocatalytic carbon dioxide reduction due to their unique carrier migration pathways, superior carrier separation efficiencies, and high redox capacities. However, the precise process of the oriented powerful electron transport remains a great challenge. Herein, an InOCd bond‐modulated S‐scheme heterojunction of In2O3/CdSe‐DETA is synthesized by a simple microwave‐assisted hydrothermal method for the accelerated photogenerated electron transfer. Meanwhile, the oxygen vacancies (Vo) of In2O3 have an electron capture effect. Consequently, thanks to the synergistic effect of this In‐Vo‐In‐O‐Cd structural units at the interface, electrons are extracted and rapidly transferred to the surface‐active sites, which improves the electronic coupling of CO2. This finding precisely adjusts the electron transfer pathway and shortens the electron transfer distance. The synergistic effect of this chemical bond established in the S‐scheme heterostructure with oxygen vacancies in In2O3 (Vo‐In2O3) provides new insights into photocatalytic CO2 reduction.

Interfacial Chemical Bond and Oxygen Vacancy‐Enhanced In2O3/CdSe‐DETA S‐scheme Heterojunction for Photocatalytic CO2 Conversion

Single/dual-metal atoms supported on carbon matrix can be modulated by coordination structure and neighboring active sites. Precisely designing the geometric and electronic structure and uncovering the structure-property relationships of single/dual-metal atoms confront with grand challenges. Herein, this review summarizes the latest progress in microenvironment engineering of single/dual-atom active sites via a comprehensive comparison of single-atom catalyst (SACs) and dual-atom catalysts (DACs) in term of design principles, modulation strategy, and theoretical understanding of structure-performance correlations. Subsequently, recent advances in several typical electrocatalysis process are discussed to get general understanding of the reaction mechanisms on finely-tuned SACs and DACs. Finally, full-scaled summaries of the challenges and prospects are given for microenvironment engineering of SACs and DACs. This review will provide new inspiration on the development of atomically dispersed catalysts for electrocatalytic application. This article is protected by copyright. All rights reserved.

Microenvironment Engineering of Single/Dual-atom Catalysts for Electrocatalytic Application.

Oxygen vacancy engineering of zinc oxide for boosting piezo-electrocatalytic hydrogen evolution

The solar-driven evolution of hydrogen from water using particulate photocatalysts is considered one of the most economical and promising protocols for achieving a stable supply of renewable energy. However, the efficiency of photocatalytic water splitting is far from satisfactory due to the sluggish electron-hole pair separation kinetics. Herein, isolated Mo atoms in a high oxidation state have been incorporated into the lattice of Cd0.5Zn0.5S (CZS@Mo) nanorods, which exhibit photocatalytic hydrogen evolution rate of 11.32 mmol g-1 h-1 (226.4 µmol h-1; catalyst dosage 20 mg). Experimental and theoretical simulation results imply that the highly oxidized Mo species lead to mobile-charge imbalances in CZS and induce the directional photogenerated electrons transfer, resulting in effectively inhibited electron-hole recombination and greatly enhanced photocatalytic efficiency.

Isolated Electron Trap-Induced Charge Accumulation for Efficient Photocatalytic HydrogenProduction.

Photothermal catalysis that utilizes solar energy to not only generate charge carriers but also supply heat input represents a potentially sustainable strategy for the efficient conversion of CO2 to valuable chemicals. It is highly desirable to develop photothermal catalysts with broadband light absorption across the whole solar spectrum, efficient photothermal conversion, and appropriate active sites. In this work, the Bi2S3@In2S3 heterostructure catalyst is fabricated via one-step solvothermal synthesis, where Bi2S3 serves as a photothermal material and synchronously affords photoexcited charge carriers. Experimental results indicate that the photoinduced charge carriers trigger H2O-assisted CO2 reduction and the elevated temperature kinetically accelerates the reaction. Furthermore, the tightly bonded heterointerfaces provide unique In–SV–Bi active centers consisting of adjacent Bi and In atoms coupled with sulfur vacancies, which reduces the energy barriers of CO2 activation and C–C coupling, facilitating the generation and dimerization of CO intermediates for highly selective C2H4 production. The integration of In–SV–Bi active sites and the photothermal effect into the Bi2S3@In2S3 catalyst induces a high rate of 11.81 μmol gcat–1 h–1 and near 90% selectivity for CO2 conversion to C2H4 under simulated sunlight without extra heat input. The catalytic mechanism is expounded by in situ characterizations and theoretical calculations. This work would provide some enlightening guidance to construct efficient photothermal catalysts for the direct transformation of CO2 to multicarbon (C2+) products with solar energy. 

Highly Selective Ethylene Production from Solar-Driven CO2 Reduction on the Bi2S3@In2S3 Catalyst with In–SV–Bi Active Sites

Photoreduction of CO 2 to C 2+ solar fuel is a promising carbon-neutral technology for renewable energy. This strategy is challenged by its low productivity due to low efficiency in multielectron utilization and slow C-C coupling kinetics. This work reports a dual-metal photocatalyst consisted of atomically dispersed Indium-Copper anchored on polymeric carbon nitride (InCu/PCN), on which the photoreduction of CO 2 delivered an excellent ethanol production rate of 28.5 μmol·g -1 ·h -1 with a high selectivity of 92%. Coupled experimental investigation with DFT calculation, this study unveils the following mechanisms underpinning the high performance of this catalyst. Essentially, In-Cu interaction enhances the charge separation by accelerating charge transfer from PCN to metal sites. In also transfers electrons to neighboring Cu via Cu-N-In bridges, increasing the electron density of Cu active sites. Furthermore, In-Cu dual-metal sites promote the adsorption of *CO intermediates and lower the energy barrier of C-C coupling.

Atomically Dispersed Indium-Copper Dual-Metal Active Sites Promoting C-C Coupling for CO2 Photoreduction to Ethanol.

Currently, the less favorable C=O hydrogenation and weak concerted acid catalysis cause unsatisfactory catalytic performance in the upgrading biomass-derived furfurals (i.e., furfural, 5-methyl furfural, and 5-hydroxymethyl furfural) to ketones (i.e., cyclopentanone, 2,5-hexanedione, and 1-hydroxyl-2,5-hexanedione). Herein, a series of partial oxidized MAX phase (i.e., Ti 3 AlC 2 , Ti 2 AlC, Ti 3 SiC 2 ) supported Pd catalysts were fabricated, which showed high catalytic activity, particularly the Pd/Ti 3 AlC 2 displayed high efficiency to the target ketones. Detailed studies of catalytic mechanism confirm that in situ hydrogen spillover generates Frustrated Lewis H + -H - pairs, which not only act as the hydrogenation sites for the selective C=O hydrogenation but also provide acid sites for the ring opening. The close intimate hydrogenation and acid sites largely promote the bifunctional catalytic reactions, substantially reducing the reported minimum reaction temperature of various furfurals by at least 30-60 °C.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/anie.202211461

H+-H- Pairs in Partial Oxidized MAX Phases for Bifunctional Catalytic Conversion of Furfurals into Linear Ketones.

Zn(II)-catalysed enantioselective addition of alcohols and tert-butyl hydroperoxide to isatin-derived N-Boc ketimines.

Post-synthetic atomically precise single-CuII sites in a thiacalix[4]arene-supported octahedral Na@Co24 cluster: the Cu-Co synergistic effect for selective photocatalytic conversion of CO2 to CO.

Jiahui Li

Papers

Atomically Dispersed Indium-Copper Dual-Metal Active Sites Promoting C-C Coupling for CO2 Photoreduction to Ethanol.

H+-H- Pairs in Partial Oxidized MAX Phases for Bifunctional Catalytic Conversion of Furfurals into Linear Ketones.

Zn(II)-catalysed enantioselective addition of alcohols and tert-butyl hydroperoxide to isatin-derived N-Boc ketimines.

Post-synthetic atomically precise single-CuII sites in a thiacalix[4]arene-supported octahedral Na@Co24 cluster: the Cu-Co synergistic effect for selective photocatalytic conversion of CO2 to CO.