Construction of CuS/ZnO Z-scheme heterojunction as highly efficient piezocatalyst for degradation of organic pollutant and promoting N2 fixation properties

Piezocatalytic technology has great potential in addressing water-system pollution and countering energy crises issues. Herein, high-performance CuS/ZnO Z-scheme heterojunction piezocatalyst was prepared by environmentally friendly solid-state chemistry approach and explored piezocatalytic performances toward degradation of organic methylene blue (MB) dye pollutant and nitrogen (N2) fixation activity under ultrasonic vibration. The CuS/ZnO piezocatalyst presents outstanding property in MB degradation process with high efficiency (94.7% in 40 min), high rate constant (0.06804 min−1) and good recyclability stability in comparison with the numerous ZnO-based piezocatalysts. In addition, this catalyst also exhibits superior piezocatalytic activity with a production rate of nitrogen fixation rate of 77.5 μmol L−1 gcat−1 h−1 in the reduction of N2 to ammonia process, which is approximately 4-folds higher than that of pristine ZnO. Such improvement was mainly attributed to the facilitating charge carriers separation via rational construction of Z-scheme heterojunction as well as enhanced redox capacity. A novel piezocatalytic Z-scheme heterojunction mechanism of CuS/ZnO has been proposed and elucidated. This work suggests that designing highly efficient CuS/ZnO piezocatalyst will be a promising candidate material for prospects application in coping with the environmental remediation pollutants and energy crisis problems.