Construction of heterojunction Bi/Bi5O7I/Sn3O4 for efficient noble-metal-free Z-scheme photocatalytic H2 evolution

A growing number of semiconductor photocatalysts have been recently reported to enhance the hydrogen evolution performance, but most of them need to work with noble metals. In this study, we constructed a ternary photocatalyst of Bi/Bi5O7I/Sn3O4 without noble metals, which can achieve a comparable or even better performance than noble metals. Bi5O7I and Sn3O4 construct a direct Z schema heterojunction due to the matched band structure, further improving the separation efficiency of electrons and holes, which greatly improves the hydrogen production performance of Sn3O4. Moreover, the superior H-2 evolution activity was achieved by metal Bi with a uniform distribution, which not only extends the light absorption range but also acts as a co-catalyst to further improve the hydrogen evolution. This work provides a new method designed for noble-metal-free photocatalytic hydrogen evolution.