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 H2 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.