Visible-Light-Driven Photocatalytic Z-Scheme Overall Water Splitting in La5 Ti2 AgS5 O7 -based Powder-Suspension System.

La5 Ti2 Cux Ag1-x S5 O7 (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 La5 Ti2 Cux Ag1-x S5 O7 materials, La5 Ti2 AgS5 O7 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 La5 Ti2 AgS5 O7 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 La5 Ti2 AgS5 O7 -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.