Piezoelectric polarization and interfacial electric field synergistically promote piezo-photocatalysis of in-situ transformed heterojunction

Abstract

Photocatalysis is a promising approach for purifying water pollutants resources, but is greatly restricted by rapid photogenerated charges recombination. Herein, Bi2O2(OH)NO3-Bi2MoO6 heterojunction photocatalysts with strong interfacial electric field are synthesized via in situ transformation method with using Bi2O2(OH)NO3 as a self-sacrificial template. The intimate interface interaction renders a large interfacial potential, which allows efficient charge separation within the heterojunction. Thus, the photocatalytic activity was well optimized compared with the pristine catalyst and composite counterpart prepared by in situ growth route. Then, the piezoelectric polarization induced by ultrasonic vibration is introduced in the photocatalytic system, which yields a piezocatalytic activity and enhancement on the separation and transfer of photogenerated charge carriers. Benefiting from the piezoelectric polarization and interfacial electric field, the in situ transformed Bi2O2(OH)NO3-Bi2MoO6 heterojunction exhibits a prominent piezo-photocatalytic performance for degradation of tetracycline, much higher than that under sole light or ultrasound irradiation source as well as the individual catalyst. This work reveals the potential of the collaboration of piezoelectric polarization and interfacial electric field in photocatalysis.