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Photocatalytic CO2 reduction plays an important role in solar energy storage and carbon balance. GaN as an III‐V semiconductor material has received extensive attention in the field of photocatalysis. In this study, the porous indium‐doped GaN (In/GaN) micro‐rods are synthesized successfully by a facile hydrothermal method and subsequent controlled atmosphere heat treatment. Photocatalytic CO2 reduction performance of In/GaN is higher than that of pure GaN due to the In doping improves the light absorption efficiency. The primary products are CO and CH4. Among the samples, 3%‐In/GaN exhibits the highest catalytic activity as well as stability and reusability. The yield rates of CO and CH4 can be reached 50.2 and 14.6 µmol · g−1 · h−1, respectively. Furthermore, density functional theory (DFT) calculations reveal that the bandgap is narrowed and the adsorption energy of CO2 molecules is improved by In doping. Moreover, the N‐vacancy detected by electron paramagnetic resonance (EPR) increases with the In doping, resulting in an increase in the number of unpaired electrons, which is conducive to carrier transport. This work provides a new study In/GaN prepared by simple method for the light‐driven photocatalytic conversion of CO2 to high‐value‐added products. [ABSTRACT FROM AUTHOR]

Limited and non-renewable fossil fuels prompt people to develop CO2 reduction technology. Polyoxometalate (POM)-based electrocatalysts have flourished due to their intriguing molecular structure and unique redox chemistry. In this Research Update, the investigations of POM-based electrocatalysts for CO2 are summarized through the following stages: first, brief fundamentals of electrochemical CO2 reduction reaction (CO2RR) and a concise introduction of POMs are introduced to provide a preliminary understanding of POM-based electrocatalysts for CO2RR; next a chronology is retrospected with respect to the development of POM-based electrocatalysts for CO2RR; subsequently, representative works are demonstrated based on the POMs themselves and POM-modified metals/alloys, and molecular catalysts as CO2RR electrocatalysts. Finally, perspectives are proposed for the challenges of the design and development of POM-based systems for electrochemical CO2RR. [ABSTRACT FROM AUTHOR]

Low selectivity and the competing reaction of hydrogen evolution are two problems in photocatalytic CO2 reduction. Herein, we deposited highly crystalline metallic Cu nanoparticles onto TiO2 photocatalysts using a solvothermal method. They were found to convert CO2 into CO without any by-products. Importantly, hydrogen evolution can be suppressed after a reaction time of 1–2 h with a high generation rate and selectivity for CO production. [ABSTRACT FROM AUTHOR]

Hematite nanoarrays are important photoanode materials. However, they suffer from serious problems of charge transfer and surface states; in particular, the surface states hinder the increase in photocurrent. A previous strategy to suppress the surface state is the deposition of an Fe-free metal oxide overlayer. Herein, from the viewpoint of atomic bonding energy, it is found that the strength of bonding around Fe atoms in the hematite is the key to suppressing the surface states. By treating the surface of hematite with Se and NaBH 4 , the Fe 2 O 3 transforms to a double-layer nanostructure. In the outer layer, the Fe-O bonding is reinforced and the Fe-Se bonding is even stronger. Therefore, the surface states are inhibited and the increase in the photocurrent density becomes much faster. Besides, the treatment constructs a nanoscale p-n junction to promote the charge transfer. Improvements are achieved in onset potential (0.25 V shift) and in photocurrent density (5.8 times). This work pinpoints the key to suppressing the surface states and preparing a high-efficiency hematite nanoarray, and deepens our understanding of hematite photoanodes., (© 2020 Wiley-VCH GmbH.)

Electrochemical reduction of CO 2 was a widespread method for CO 2 conversion into valuable chemical fuel. C 2 H 4 is an important product from CO 2 reduction. However, conversion of CO 2 into the hydrocarbon C 2 H 4 faced large energy barriers. Herein, we, for the first time, achieve a high efficiency for electrochemical conversion of CO 2 to C 2 H 4 on a tin-modified CuO. By modifying with Sn, we obtained a related low onset potential of C 2 H 4 as positive as -0.8 V versus RHE and a high Faradaic efficiency of C 2 H 4 as high as 22% at -1.0 V ( vs RHE). According to density functional calculation, the Sn dopant mainly enriched the electron density of CuO, while it was electron-poor in the Sn dopants. The rate of CO 2 reduction can be enhanced on Cu nanosheets with higher electron density. We believed that this work would promote the development of two-dimensional catalysts for CO 2 conversion and deepen the understanding of doping on CO 2 reduction.