Abstract: Photocatalytic technologies have been universally applied in the domains of hydrogen production, environmental purification, CO₂ reduction, catalytic organic synthesis, and other major fields owing to their environmental friendliness, convenient operation, and absorbing sunlight as the driving force. The core of photocatalytic technology is photocatalyst. Hence, it is greatly essential to fabricate stable, high-efficiency, and visible-light response photocatalysts. Among various visible-light-response photocatalysts, ZnIn₂S₄, a ternary metal sulfide, has attracted extensive attention due to its prominent advantages of simple synthesis, excellent stability, and appropriate band structure. However, the low utilization of solar energy and rapid recombination of photogenerated charges as same as inferior redox capacity are still the distinct shortcomings that significantly block the increase of photocatalytic efficiency for ZnIn₂S₄ photocatalyst. Fortunately, the above evident shortcomings can be simultaneously resolved by constructing heterojunctions between ZnIn₂S₄ with other semiconductors. In recent years, various semiconductor photocatalysts (such as oxides (TiO₂, WO₃, In₂O₃), sulfides (ZnS, FeS₂, CoS), oxysalts (Bi₂MoO₆, ZnWO₄, NaTaO₃), organics (g-C₃N₄, COF, PDIIM), etc.) have been combined with ZnIn₂S₄ to construct ZnIn₂S₄-based S-scheme heterojunctions with the aim at greatly increasing its photocatalytic efficiency. Herein, this review presents a systematic description of the currently popular ZnIn₂S₄-based S-scheme heterojunction photocatalyst, which includes the research background, scientific mechanism, design principles, preparation strategies, and characterization methods of ZnIn₂S₄-based S‐scheme heterojunctions. Moreover, the extensive photocatalytic applications of ZnIn₂S₄-based S-scheme heterojunctions have been detailly described by classification examples, including hydrogen production, CO₂ reduction, environmental purification, and other applications. Finally, several drawbacks on the synthetizations, modifications, and applications of ZnIn₂S₄-based S-scheme heterojunction have been proposed, and their corresponding prospects have also been propounded in terms of their future development.

Key words: Photocatalysis, ZnIn₂S₄, Heterojunction, S-scheme, Applications