Hierarchical core-shell carbon nanofiber@ZnIn₂S₄ composites for enhanced hydrogen evolution performance.

Improvement of hydrogen evolution ability is an urgent task for developing advanced catalysts. As one of the promising visible-light photocatalysts, ZnIn2S4 suffers from the ultrafast recombination of photoinduced charges, which limits its practical application for efficient solar water splitting. Herein, we reported a two-step method to prepare hierarchical core-shell carbon nanofiber@ZnIn2S4 composites. One-dimensional carbon nanofibers were first prepared by electrospinning and carbonization in N2. The subsequent solvothermal process led to the in situ growth of ZnIn2S4 nanosheets on the carbon nanofibers to fabricate hierarchical structure composites. The hierarchical core-shell configuration structure can help to form an intimate contact between the ZnIn2S4 nanosheet shell and the carbon nanofiber backbone compared with the equivalent physical mixture and can facilitate the interfacial charge transfer driven by the excitation of ZnIn2S4 under visible-light irradiation. Meanwhile, the ultrathin ZnIn2S4 nanosheets were uniformly grown on the surface of the carbon nanofibers, which can avoid agglomeration of ZnIn2S4. These synergistic effects made this unique hierarchical structure composite exhibit a significantly higher visible-light photocatalytic activity toward hydrogen evolution reaction compared with pure ZnIn2S4 or a physical mixture of ZnIn2S4 and carbon nanofibers in the absence of noble metal cocatalysts.