Interfacial reconstruction of 2D/2D ZnIn2S4/HNb3O8 through Nb-S bonds for efficient photocatalytic H2 evolution performance

Abstract

Heterojunction structure of the composite photocatalyst with the intimate interface and sufficient contact areas is the key to achieve superior photogenerated charge carriers migration efficiency. However, it still remains a great challenge. Herein, a novel ZnIn2S4/HNb3O8 heterojunction with a strong Nb-S bond connected 2D/2D in-plane interface is successfully fabricated via a two-step synthesis method. Due to the similarity of the chemical property, S precursors for ZnIn2S4 are preferred trapped by the O defects on HNb3O8, which induce the formation of Nb-S bond in the 2D/2D interface under the hydrothermal process. The unique 2D/2D structure endows the heterojunction with large interfacial area and the Nb-S bond as high-speed channels facilitate the interfacial electrons transfer. Furthermore, Kelvin probe test demonstrates an interfacial electric field oriented from HNb3O8 to ZnIn2S4 is formed as driving force for the interface charge transfer. As a result, the photoexcited electrons may directionally migrate across the interface, thereby promoting the photocatalytic activity. The optimal H2 evolution amount reaches 95.2 mmol g−1, corresponding to 10.8 times of ZnIn2S4. The in-situ construction of chemical bonded heterojunction will provide a reference for designing high-efficiency heterojunction photocatalyst.

Keywords

• Interfacial engineering
• 2D/2D heterojunction
• ZnIn2S4/HNb3O8
• H2 generation
• Photocatalysis