Exploring the photothermal effect in the photocatalytic water splitting over Type II ZnIn2S4/CoFe2S4 composites.

Hydrogen is increasingly acknowledged as a viable alternative to traditional fossil fuels. However, the photothermal properties of CoFe₂S₄, a photocatalyst displaying metal-like behavior, have not been adequately explored in the context of photocatalytic H₂ generation. To improve photocatalytic hydrogen evolution, it is crucial to understand how to expedite the transfer of photogenerated electrons and the dissociation of H-OH bonds for enhanced hydrogen ion release. Herein, a type-II heterostructure was constructed between CoFe₂S₄ nanosheets and ZnIn₂S₄ nanoparticles, a non-precious metal photocatalyst, which effectively separates photogenerated carriers and holes. More importantly, the photothermal effect and localized surface plasmon resonance (LSPR) effects induced by CoFe₂S₄ improved the sluggish kinetics of water dissociation. The CoFe₂S₄/ZnIn₂S₄-5 photocatalyst achieved H₂ evolution rate of 6.84 mmol·g^-1·h^-1, and an apparent quantum efficiency of 15.6 % at 400 nm, significantly enhancing the efficiency of photocatalytic splitting for hydrogen production. This work advances the application of metal CoFe₂S₄ in solar-to-fuel conversion and offers valuable insights for designing semiconductor-based photothermally assisted photocatalytic systems.