Constructing heterojunction of BiPO4/SnS2 nano-flower with sharp-tips effect and bi-functional catalyst as a direct Z-scheme system for high-efficiency photocatalytic performance

Designing heterojunction structure of Z-scheme system and modulating the electronic properties of catalysts is an effective method to boost photo-generated carrier separation efficiently. In this work, a brand new Z-scheme BiPO4/SnS2 three dimension (3D) flower heterogeneous composite with sharp-tips effect and bi-functional catalyst was successfully prepared. Combining the sharp-tips effect, BiPO4/SnS2 with Z-scheme system possesses the highest catalytic activity due to heterojunction structure between SnS2 and BiPO4, which is beneficial to efficient separation of photogenerated electrons and holes, improve the electronic distribution, make it easier to concentrate electrons to the tip position, shorten the distance of charge transmission and improve photocatalytic efficiency. As a result, the BiPO4/SnS2 composites possess excellent photocatalytic properties and the rate of degradation toward MB under visible light for 80 min is 1.23 and 1.45 times than that of pure SnS2 and BiPO4, respectively. On the basis of radical-trapping experiment and band structure analysis, Z-scheme heterojunction was formed between SnS2 and BiPO4. And the BiPO4/SnS2 composites show the highest H2-generation rate of 303 μmol h−1 g−1 without any noble metal as cocatalyst under visible light, which is about 1.43 and 2.01 times higher than that of pure SnS2 and pure BiPO4, respectively. So BiPO4/SnS2 composite can act as bi-functional catalyst in the degradation or hydrogen production. This strategy of constructing a heterojunction structure and adjusting the electronic distribution of catalysts in visible-light photocatalysts could provide an insight to boost the photocatalytic activity for environmental remediation, H2-generation and water treatment.