Hierarchical\nCore–Shell Carbon Nanofiber@ZnIn₂S₄ Composites\nfor Enhanced Hydrogen Evolution Performance

Abstract

Improvement\nof hydrogen evolution ability is an urgent task for\ndeveloping advanced catalysts. As one of the promising visible-light\nphotocatalysts, ZnIn₂S₄ suffers from the ultrafast\nrecombination of photoinduced charges, which limits its practical\napplication for efficient solar water splitting. Herein, we reported\na two-step method to prepare hierarchical core–shell carbon\nnanofiber@​ZnIn₂S₄ composites. One-dimensional\ncarbon nanofibers were first prepared by electrospinning and carbonization\nin N₂. The subsequent solvothermal process led to the in\nsitu growth of ZnIn₂S₄ nanosheets on the carbon\nnanofibers to fabricate hierarchical structure composites. The hierarchical\ncore–shell configuration structure can help to form an intimate\ncontact between the ZnIn₂S₄ nanosheet shell\nand the carbon nanofiber backbone compared with the equivalent physical\nmixture and can facilitate the interfacial charge transfer driven\nby the excitation of ZnIn₂S₄ under visible-light\nirradiation. Meanwhile, the ultrathin ZnIn₂S₄ nanosheets were uniformly grown on the surface of the carbon nanofibers,\nwhich can avoid agglomeration of ZnIn₂S₄. These\nsynergistic effects made this unique hierarchical structure composite\nexhibit a significantly higher visible-light photocatalytic activity\ntoward hydrogen evolution reaction compared with pure ZnIn₂S₄ or a physical mixture of ZnIn₂S₄ and carbon nanofibers in the absence of noble metal cocatalysts.