Bi0·5Na0·5TiO3/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 Bi 0·5 Na 0·5 TiO 3 /ZnO composites was achieved by heterojunction construction for energy band regulation and synchronously mechanical energy harvesting from piezoelectric effect. The formation of heterojunctions between Bi 0·5 Na 0·5 TiO 3 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 Bi 0·5 Na 0·5 TiO 3 /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 Bi 0·5 Na 0·5 TiO 3 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.