Water Splitting and CO2 Reduction under Visible Light Irradiation Using Z-Scheme Systems Consisting of Metal Sulfides, CoOx-Loaded BiVO4, and a Reduced Graphene Oxide Electron Mediator

Metal sulfides are highly active photocatalysts for water reduction to form H-2 under visible light irradiation, whereas they are unfavorable for water oxidation to form O-2 because of severe self-photomddation (i.e, photocorrosion). Construction of a Z scheme system is a useful strategy to split water into H-2 and O-2 using such photocorrosive metal sulfides because the photogenerated holes in metal sulfides are efficiently transported away. Here, we demonstrate powdered Z-scheinatic water splitting under visible light and simulated sunlight irradiation by combining metal sulfides as an H-2-evolving photocatalyst, reduced graphene oxide (RGO) as an electron mediator, and a visible-light-driven BiVO4 as an O2- evolving photocatalyst. This Z-sthernatic.photocatalyst composite is also active in CO2 reduction using water as the sole electron donor under visible light.