Abstract: Photocatalysis has emerged as a green and sustainable technology that directly captures, converts, and stores solar energy, offering a viable solution to alleviate the growing energy crisis and environmental deterioration. As a novel metal chalcogenide, ZnIn₂S₄ has garnered widespread research interest in photocatalysis by virtue of its non-toxicity, facile and controllable synthesis, favorable photochemical stability, and visible-light-responsive band structure. Nevertheless, its practical photocatalytic applications are still severely constrained by the insufficient utilization of solar spectrum and the fast recombination of photogenerated charge carriers. The emerging S-scheme heterojunction strategy can effectively tackle these issues by facilitating charge separation while maintaining robust redox capacities, which greatly promotes the practical application of ZnIn₂S₄-based photocatalysts. This review first systematically introduces the intrinsic physicochemical properties of ZnIn₂S₄ and discusses its fundamental photocatalytic reaction mechanisms. Thereafter, the corresponding charge transfer and migration behaviors as well as advanced characterization techniques for mechanism validation are summarized, and the rational design principles of ZnIn₂S₄-based S-scheme heterojunctions are elaborated. On this basis, the latest research advances of ZnIn₂S₄-based S-scheme heterojunctions for diverse photocatalytic applications are comprehensively reviewed. Finally, current challenges, reasonable construction strategies, and future perspectives are proposed to advance the development of high-efficiency ZnIn₂S₄-based S-scheme photocatalysts.

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