Doping photocatalyst for water splitting

In photocatalytic water splitting, a photocatalyst, typically a semiconductor material, is used to absorb light energy and initiate the water splitting reaction. When light is absorbed by the photocatalyst, it creates electron-hole pairs. The excited electrons can then reduce water, while the holes can oxidize water. However, there are several challenges associated with photocatalytic water splitting, mainly including low efficiency, limited visible light absorption, and photocorrosion of the photocatalyst. Thus, various strategies such as heterojunction formation, nanostructure design, cocatalysts utilization, dye sensitization, surface plasmonic enhancement, doping, and defect control are being explored to solve these problems and break the efficiency bottleneck.

Doping, in particular, has garnered significant attention. Various studies have demonstrated its efficacy. For instance, Kudo's team achieved an apparent quantum yield (AQY) exceeding 50% through metal oxide modification. Nitrogen doping in TiO₂, as reported by Asahi et al., proved crucial for band gap narrowing and enhanced photocatalytic activity. Domen et al. introduced a solid solution of gallium and zinc nitrogen oxide (Ga_1–xZn_x)(N_1–xO_x) for visible light water splitting. Chen et al. explored disorder introduction in TiO₂ nanophase layers via hydrogenation to enhance solar absorption. Takata et al. achieved overall water splitting using a modified aluminum-doped strontium titanate (SrTiO₃:Al) photocatalyst with an external quantum efficiency of up to 96%.

Recently, Prof. Wenfeng Shangguan's team from Shanghai Jiao Tong University, China, integrated their research with other significant studies to provide a comprehensive review of energy band structure, microstructure, defect regulation, and doping strategies influencing photocatalytic activity. Their focus on doping rare earth elements into bismuth-based composite oxides aims to enhance the conduction band minimum and achieve overall water splitting under visible light. Their innovative asymmetric doping technique—Selected Local Gradient Doping—allows controlled release of doped ions, promising significant contributions to novel materials exploration and energy conversion efficiency enhancement in photocatalytic water splitting under visible light. The results were published in Chinese Journal of Catalysis (https://doi.org/10.1016/S1872-2067(23)64637-6).

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Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 15.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

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