Visible Light-Driven Z‑Scheme Water Splitting Using Oxysulfide H2 Evolution Photocatalysts

• Published in: The journal of physical chemistry letters 2016-10, Vol.7 (19), p.3892-3896
• Main Authors: Ma, Guijun, Chen, Shanshan, Kuang, Yongbo, Akiyama, Seiji, Hisatomi, Takashi, Nakabayashi, Mamiko, Shibata, Naoya, Katayama, Masao, Minegishi, Tsutomu, Domen, Kazunari
• Format: Article
• Language: English
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.6b01802

A Sm2Ti2S2O5 (STSO) oxysulfide photocatalyst prepared by a novel flux method showed a higher degree of crystallinity and greater photocatalytic activity than that prepared by conventional polymerized complex and sulfurization processes. Co-loading with both IrO2, as an oxidative cocatalyst, and Pt, as a reductive cocatalyst, was found to be essential for promoting the photocatalytic activity of the STSO. Visible light-driven Z-scheme water splitting into H2 and O2 was realized by utilizing the STSO photocatalyst for H2 evolution in conjunction with a WO3 photocatalyst treated with H+ and Cs+ and loaded with PtO x for O2 evolution, and a triiodide/iodide (I3 –/I–) redox couple as a shuttle electron mediator. Various other narrow band gap oxysulfide photocatalysts with H2 evolution activity, such as La5Ti2CuS5O7 and La6Ti2S8O5, were also shown to be applicable as H2 evolution photocatalysts in the present Z-scheme water splitting system.