Triple-functional Co2SnO4-enabled S-scheme heterojunction with photothermal promotion for efficient solar-driven hydrogen evolution

Abstract

Photocatalytic hydrogen production offers a sustainable route for solar energy conversion, yet its efficiency is hindered by rapid charge recombination, limited light absorption and slow reaction kinetics. In this study, we introduce a strategically engineered Co2SnO4@ZnIn2S4 S-scheme heterojunction photocatalyst that synergistically enhances charge separation, photothermal conversion and catalytic activity to overcome these challenges. Using a simple solvent self-assembly method, we develop a heterostructure in which Co2SnO4 nanoparticles serve as a versatile component by: (1) extending light absorption into the near-infrared (800-1400 nm) range for efficient solar-to-thermal conversion, (2) creating an S-scheme charge transfer pathway that enhances electron-hole separation while maintaining high redox potentials, and (3) providing numerous active sites to accelerate proton reduction kinetics. The optimized photocatalyst achieves an impressive hydrogen evolution rate of 12.56 mmol g-1 h-1 and an apparent quantum efficiency of 12.96% at 420 nm. Comprehensive experimental and theoretical analyses validate the S-scheme charge transfer mechanism and quantify the photothermal and catalytic contributions to reaction enhancement. This work not only demonstrates a highly efficient photocatalytic system but also provides critical insights into designing multifunctional heterostructures for solar fuel generation, paving the way for practical renewable energy applications.