Visible‐Light‐Driven Photocatalytic Z‐Scheme Overall Water Splitting in La5Ti2AgS5O7‐based Powder‐Suspension System

• Published in: ChemSusChem 2019-05, Vol.12 (9), p.1906-1910
• Main Authors: Song, Zhimin, Hisatomi, Takashi, Chen, Shanshan, Wang, Qian, Ma, Guijun, Li, Shikuo, Zhu, Xiaodi, Sun, Song, Domen, Kazunari
• Format: Article
• Language: English
• Subjects: Chemical evolution; Hydrogen evolution; oxysulfides; Photocatalysis; Photocatalysts; Solid solutions; Suspension systems; visible light; Water splitting; Z-scheme
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201802306

La5Ti2CuxAg1−xS5O7 (x=0–1) is a type of long‐wavelength‐responsive oxysulfide photocatalysts for hydrogen evolution and has been demonstrated to enable the Z‐scheme water‐splitting coupling with oxygen evolution photocatalysts (OEPs) in the particulate sheet. Among La5Ti2CuxAg1−xS5O7 materials, La5Ti2AgS5O7 was found to have the highest performance on Z‐scheme overall water splitting in conjunction with PtOx‐WO3 as an OEP and a triiodide/iodide (I3−/I−) redox couple as a shuttle electron mediator in a powder‐suspension system. Loading Pt/NiS on La5Ti2AgS5O7 benefitted the Z‐scheme to achieve an apparent quantum yield of 0.12 % at 420 nm. The results for this powder‐suspension system differ from earlier studies on photocatalyst sheet configurations, in which p‐type doping and the formation of a solid solution could effectively enhance the water‐splitting activity. This work not only demonstrates a La5Ti2AgS5O7‐based Z‐scheme water‐splitting photocatalyst but also improves the understanding of the difference between particulate sheets and a powder‐suspension system available in an optimal strategy for water splitting. Lighting up the water: Visible light‐driven Z‐scheme water splitting with Pt/NiS‐loaded LTA as hydrogen evolution photocatalyst, PtOx‐WO3 as oxygen evolution photocatalyst, and I3−/I− as redox mediator, achieves an apparent quantum yield of 0.12 % at 420 nm. The optimization strategy for Z‐scheme water splitting in a powder‐suspension system differs from that for particulate photocatalyst sheets or a photoelectrochemical system.