Controllable multi-interface coverage of gradient heterojunction nanofibers with one-dimensional structure for photocatalytic hydrogen evolution

Abstract

Multi-interface gradient heterojunction nanofibers represent a promising architecture for photocatalytic hydrogen evolution. In this work, such nanofibers were fabricated via electrospinning coupled with secondary growth technology, integrating a spatially separated structure with a core–shell configuration. This design not only establishes host–guest interfaces to facilitate charge separation but also enhances the accessibility of photogenerated electrons and holes during photocatalytic reactions.The simulations indicate that these multi-interface gradient heterojunction nanofibers have an enhanced potential difference (TiO₂/g-C₃N₄/ZnIn₂S₄ MHNFs: 0.467 V) than core–shell binary heterojunction (TiO₂/g-C₃N₄ HNFs: 0.105 V). Experimentally, the TiO₂/g-C₃N₄/ZnIn₂S₄ MHNFs have better charge separation and transfer ability, as evidenced by photoluminescence, photovoltage, and photoelectrochemical investigations. The multi-interface exposed multiple reactive sites, and gradient energy band provide an effective photocarrier transfer path, thereby their photocatalytic hydrogen evolution rate was enhanced to 4005.9 μmol g^-1 h⁻¹, about 2.5 times higher than that of TiO₂/g-C₃N₄ HNFs with single core–shell interface, and also higher than the other single component sample. This study demonstrates a rational design strategy for high-performance photocatalysts through the construction of multi-interface gradient heterojunction nanofibers, offering effective framework for solar energy conversion applications.