Hierarchical Co₉S₈/ZnIn₂S₄ Nanoflower Enables Enhanced Hydrogen Evolution Photocatalysis

Photocatalytic water splitting with clean solar energy is a sustainable way to produce green hydrogen (H2) fuel. Here, an efficient, visible-light-responsive hierarchical Co9S8/ZnIn2S4 photocatalyst is designed by decorating Co9S8 nanoparticles on ZnIn2S4 nanoflower through a two-step solvothermal process for photocatalytic H2 evolution. Two photoactive sulfide–sulfide integrations in a stable, hierarchical, and flower-like Co9S8/ZnIn2S4 heterojunction, provide large surface areas with rich active centers and endow a quick separation and transfer of photoinduced electrons and holes. With the optimal loading amount of Co9S8, the Co9S8/ZnIn2S4 photocatalyst, under visible-light illumination, free of any cocatalysts, reaches a high hydrogen evolution rate of 126.7 μmol h–1 or 12.67 mmol h–1 g–1 with high stability, which is 6 times higher than that of individual ZnIn2S4. Our effort may give some inspirations to the delicate design of competent novel structured photocatalysts for reinforcing photocatalytic performance.