Twin-brush ZnO mesocrystal for the piezo-activation of peroxymonosulfate to remove ibuprofen in water: Performance and mechanism

Mesocrystals are highly ordered mesoporous superstructures with rich defects and high internal porosity, which are featured by the anisotropic charge migration in catalysis. In this work, we first used twin-brush hierarchical structures of ZnO (TB-ZnO) as piezoelectric mesocrystal with abundant oxygen vacancies to activate peroxymonosulfate (PMS) under piezoelectric activation. Compared with non-mesocrystal of common ZnO nanorods (NR-ZnO), TB-ZnO exhibited 3.7 times of performance for the ibuprofen (IBP) pollutants degradation in the presence of PMS and ultrasonic vibration, and achieved a high PMS utilization efficiency that exceeds the state-of-the-art catalysts. Experimental and theoretical results revealed that the presence of oxygen vacancies together with order mesoporous superstructures in TB-ZnO promoted the electron transfer, decreased the reaction barriers, and facilitated the mass transfer, thus enabling more electrons to participate in PMS activation. These findings open up an avenue to improving the utilization efficiency of PMS in the piezo-activation system for environmental remediation.