Integration of piezoelectric effect into a Au/ZnO photocatalyst for efficient charge separation

Abstract

Semiconductor photocatalysts have shown high potential for application in environmental remediation and clean energy generation; however, their catalytic activities are still low due to severe charge recombination at the surface and in the bulk of the photocatalyst. Herein, a highly active photocatalytic system was constructed by integrating piezoelectric effect into the Au/ZnO photocatalyst to promote the simultaneous separation of photogenerated carriers at the surface and in the bulk; as expected, the Au/ZnO photocatalyst demonstrated superior synergistic catalyst activities, which were a combination of piezo- and photo-catalytic activities. Under the ultrasonic and ultraviolet light, the Au/ZnO nanorod composite could completely degrade RhB within 20 min, which was much lower than the degradation time required under other conditions. The research results indicated that the Schottky barrier formed by Au and ZnO enhanced the separation of photogenerated carriers at the ZnO surface, and the ZnO piezoelectric effect induced by the ultrasonic wave enhanced the separation of ZnO bulk photogenerated carriers.