Facile synthesis of ZnO/ZnS heterojunction nanoarrays for enhanced piezo-photocatalytic performance

Constructing heterojunction is a promising approach to enhance the piezo-photocatalytic performance of ZnO nanostructures. In this study, ZnO/ZnS heterojunction nanoarrays have been synthesized by facile vulcanizing surface of wurtzite ZnO nanorods into blende ZnS nanoparticles through hydrothermal method. Both the synthesized wurtzite ZnO nanorods and blende ZnS nanoparticles are piezoelectric semiconductors with wide band gaps. For degrading methyl blue solution under UV irradiation and ultrasonic sonication, it is found that both the piezocatalytic, photocatalytic and piezo-photocatalytic performances of ZnO/ZnS nanoarrays are much higher than those of pure ZnO. In addition, the piezo-photocatalytic degradation rate of ZnO/ZnS nanoarrays can be further increased by improving the ultrasonic power. The mechanism can be attributed to the synergetic effect of piezoelectric effect and heterojunction photocatalysis.