Nanostructured Metal Sulfides: Classification, Modification Strategy, and Solar‐Driven CO2 Reduction Application

Solar‐driven conversion of CO2 into high value‐added fuels is expected to be an environmental‐friendly and sustainable approach for relieving the greenhouse gas effect and countering energy crisis. Metal sulfide semiconductors with wide photoresponsive range and favorable band structures are suitable photocatalysts for CO2 photoreduction. This review summarizes the recent progress on metal sulfide semiconductors for photocatalytic CO2 reduction. First, the fundamentals, mechanisms and some principles, like product selectivity, of photocatalytic CO2 reduction are introduced. Then, according to the elemental composition, the metal sulfide photocatalysts applied for CO2 reduction are classified into binary (CdS, ZnS, MoS2, SnS2, Bi2S3, In2S3,Cu2S, NiS/NiS2, and CoS2), ternary (ZnIn2S4, CdIn2S4, CuInS2, Cu3SnS4, and CuGaS2), and quaternary (Cu2ZnSnS4) systems, in which their crystal structures, photochemical characteristics, and photocatalytic CO2 reduction applications are systematically demonstrated. Especially, the diverse modification strategies for improving the activity and product selectivity of photocatalytic CO2 reduction on these metal sulfides are summarized. Finally, the current challenges and future directions for the development of metal sulfide photocatalysts for CO2 reduction are proposed. This review is expected to serve as a powerful reference for exploiting high‐efficiency metal sulfide photocatalysts for CO2 conversion and furthering related mechanism understanding. Metal sulfide semiconductors present unique optical/electronic characteristics, which are advantageous for CO2 photoreduction. The advancements in binary, ternary, and quaternary metal sulfide photocatalysts in CO2 photoreduction are elaborately summarized, and the effects of various modification strategies on the reduction activity and product selectivity are highlighted, providing a reference for development of efficient metal sulfides for photocatalytic CO2 reduction to carbonaceous fuels.