BiNaTiO/ZnO Z-scheme heterojunction for piezo-photocatalytic water remediation: Mechanical energy harvesting and energy band configuration.

The decaying photocatalytic rate caused by carrier recombination is a thorny problem that has not been properly solved. Improvement of photocatalysis can be achieved through structural innovation, diversification of catalytic modes, or a combination of both. Herein, effective separation of photo-generated carriers in BiNaTiO/ZnO composites was achieved by heterojunction construction for energy band regulation and synchronously mechanical energy harvesting from piezoelectric effect. The formation of heterojunctions between BiNaTiO and ZnO was confirmed by electron microscopy and analysis of X-ray photoelectron spectroscopy spectra. The degradation performance of Rhodamine B, a representative industrial dye contaminant, was optimized through the formation of BiNaTiO/ZnO heterojunctions and ultrasonic vibration harvesting. Their band structures were described in detail and electrochemical tests were performed to substantiate a novel Z-scheme heterostructure that can explain the carrier separation and transfer processes in catalysis. The piezoelectric polarization field generated by the piezoelectric effect of both BiNaTiO and ZnO coordinates perfectly with the photocatalysis, enabling the piezo-photocatalysis. Our research opens a promising avenue in alleviating charge carrier complexation through heterojunction construction and mechanical strain for future pollutants degradation via catalysis.