Metal-sulfide photocatalysts for solar-fuel generation across the solar spectrum

Metal sulfides have been widely used as photocatalysts in photocatalytic solar-fuel generation, owing to their low cost and proper band alignment. However, the efficiency and stability of this solar-driven reaction are limited by the low activity and high recombination rate of carriers, which originate from the intrinsic properties of metal sulfides. In the past few decades, many strategies have been proposed to enhance solar-fuel generation across the solar spectrum, such as building micro-nanostructures, doping with metal/nonmetal elements, constructing heterostructures, and introducing cationic/anionic vacancies. This review introduces the fundamental optical properties and preparation methods of metal sulfides. Subsequently, we discuss and summarize modification strategies to promote photocatalytic performance in line with the differences in the light-absorption range. Finally, associated challenges and perspectives for developing highly efficient metal-sulfide-based photocatalysts are investigated.