ZnO/CuO Piezoelectric Nanocatalysts for the Degradation of Organic Pollutants

The p–n heterojunction nanocatalyst was successfully synthesized by decorating the surface of ZnO nanorods with CuO by using a low-temperature synthesis method. It was used as the driving force for the removal of tetracycline (TC) in water with mechanical stirring. Different ratios of ZnO/CuO piezoelectric nanocatalysts were examined. The nanoscale ZnO/CuO catalyst achieved a 98% removal rate of TC in water after 120 min. The main active species for TC degradation were identified as hydroxyl radicals (•OH) and superoxide radicals (•O2–) by quenching experiments. The piezoelectric current generated by ZnO/CuO-1.5 was found to be 3.1 and 6.2 times higher than those of pure ZnO and CuO, respectively, due to the formation of a p–n heterojunction structure and built-in electric field situation. The facile and low-temperature synthesis process of the ZnO/CuO nanocatalyst with superior removal rates provides practical support for large-scale application in wastewater treatment.