Visible-Light-Driven Photocatalytic Z-scheme Overall Water Splitting in La5Ti2AgS5O7-based Powder Suspension System

摘要： La5Ti2CuxAg1-xS5O7 (x=0-1) is a kind 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 (OEP) the particulate sheet. We herein report that among La5Ti2CuxAg1-xS5O7, 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 powder suspension system. Loading Pt/NiS on La5Ti2AgS5O7 benefits the Z-scheme to achieve an apparent quantum yield of 0.12% at 420 nm. The finding in powder suspension system is opposite to the earlier study on photocatalyst sheet configurations in which p-type doping and the formation of a solid solution can effectively enhance the water-splitting activity. This work not only shows a La5Ti2AgS5O7-based Z-scheme water splitting photocatalyst, but also may present a better understanding for the difference between particulate sheet and powder suspension system available in an optimal strategy for water splitting.