Sulfur vacancy engineering of metal sulfide photocatalysts for solar energy conversion

Metal sulfides have attracted interest in the field of photocatalysis because of their excellent optical, physical, and chemical properties. However, the photocatalytic performance of sulfide is far from satisfactory due to the rapid recombination of photogenerated charge carriers and serious photocorrosion. Sulfur vacancy engineering is one of the effective strategies for improving photocatalytic performance, and it not only can improve their optical and electrical properties but also can change their surface properties. In this review, sulfur vacancy engineering is summarized and discussed, and several common metal sulfide photocatalysts (e.g., binary sulfides, ternary sulfides, and other sulfides) and their reaction mechanisms are reviewed. Recent advances in sulfur-vacancy-engineered sulfides for photocatalytic solar fuels and environmental remediation are also evaluated. The vital roles of sulfur vacancy in promoting charge separation and inhibiting photocorrosion are summarized. Finally, the development prospects and opportunities of sulfur–vacancy-engineered metal sulfide photocatalysts for solar energy conversion are proposed.