Recent Progress of Metal Halide Perovskite‐Based S‐Scheme Heterojunction for Solar Energy Conversion

Semiconductor photocatalysis provides a sustainable route for solar‐to‐fuel conversion to mitigate global energy and environmental crises. Metal halide perovskites (MHPs) have emerged as promising photocatalysts due to their low cost, tunable compositions and band structures, excellent photoelectric properties, and scalable preparation. Nevertheless, rapid bulk charge recombination and narrow light absorption range severely restrict their photocatalytic efficiency. Fabricating S‐scheme heterojunctions has become an advanced modification strategy to accelerate charge separation and transfer while maintaining high redox potentials. This review systematically elucidates the crystal and physicochemical properties of MHPs, the evolution of S‐scheme heterojunctions, and the advantages of MHP‐based S‐scheme photocatalysts. The synthesis strategies, underlying mechanisms, and advanced characterization techniques for tracking charge behavior in such heterojunctions are summarized. Additionally, recent advances in MHP‐based S‐scheme photocatalysts are reviewed across hydrogen evolution, CO 2 photoreduction, pollutant remediation, and H 2 O 2 photosynthesis. Finally, the current challenges and future perspectives of these composite photocatalytic systems are proposed.