Oxygen Vacancies and Lattice Distortion Synergistically Enhanced Piezocatalysis of CaZn2(BO3)2 for Nonantibiotic Pharmaceutical Degradation.

Abstract

Piezocatalysis, an emerging green and advanced oxidation technology, has recently been widely researched in environmental treatment. However, the limited polarization efficiency of the piezocatalyst is a serious bottleneck for its practical application. The search for an excellent piezocatalyst with a high piezoelectric coefficient and abundant reactive sites remains an urgent task that needs to be developed. Herein, a piezocatalyst, CaZn2(BO3)2 (CZBO), obtained by quenching has an excellent piezocatalysis, which exhibited superior activity for ibuprofen (IBP) and carbamazepine (CBZ) removal with 100% and 83.8% efficiency under ultrasonic cavitation (120 W, 40 kHz) within 36 min, respectively. The outstanding piezocatalytic degradation was attributed to the strong polarization of the material under the synergistic effect of oxygen vacancies (OVs) and lattice distortion, which effectively facilitated the generation of a high concentration of reactive oxygen species (ROS). The lattice distortion induced by O-deficient [BO3] plane units can promote the e- and h+ pair separation and transportation, and the OVs with abundant electron-rich regions can significantly decrease O-O bond activation energy, thus collaboratively contributing to the high production of ROS for IBP and CBZ degradation. This work provides a simple avenue for enhancing piezoelectric polarization based on the OVs and lattice distortion and proposes insights into the reaction mechanisms for degrading nonantibiotic pharmaceuticals in wastewater.