Enhanced piezo-photocatalytic activity of oxygen-deficient ZnO nanoparticles prepared by facile precipitation

Oxygen-deficient ZnO nanoparticles with excellent piezo-photocatalytic activity are successfully prepared by thermal decomposition of hydrozincite (Zn 5 (OH) 6 (CO 3 ) 2 ) obtained via a simple precipitation method. The piezo-photocatalytic degradation of organic dyes (Rhodamine B) and antibiotics (tetracycline) over the obtained ZnO nanoparticles is investigated. The results indicated that ZnO nanoparticles obtained through calcination at 500 °C (ZnO500) exhibit more oxygen vacancies and superior piezo-photocatalytic activity. Under the simultaneous action of ultrasound and light for 40 min, its degradation efficiency and rate constant for Rhodamine B achieve 96.2 % and 0.094 min −1 , respectively, and the synergistic index of ultrasound and light is as high as 6.26. This high synergy is attributed to the piezoelectric polarization induced by ultrasound, which effectively promotes the separation of photo generated electrons and holes. Moreover, the introduction of oxygen vacancies increases the free carrier concentration in ZnO nanoparticles and generates more reactive species, thereby enhancing the piezo-photocatalytic activity of ZnO. Additionally, the 120 min degradation efficiency and rate constant of ZnO500 for tetracycline reach 93.3 % and 0.023 min −1 , respectively, demonstrating good versatility. This work demonstrates the application prospect of high-performance piezo-photo catalysts prepared by a simple method in the treatment of organic pollutants in water.