Oxygen vacancy-mediated peroxydisulfate activation and singlet oxygen generation toward 2,4-dichlorophenol degradation on specific CuO1-x nanosheets.

Durable and stable removal of 2,4-dichlorophenpl (2,4-DCP) by CuO1-x nanosheets is reported. CuO1-x nanosheets were fabricated by a simple defect engineering strategy and greatly increased the efficiency of peroxydisulfate (PDS) activation to improve 2,4-DCP removal by introducing abundant oxygen vacancy (Vo) to produce an electron-rich surface. Results showed that CuO1-x nanosheets exposed more Vo as active sites for PDS activation as compared with that of CuO nanoparticles, giving rise to dramatic enhancement of catalytic performance with ultrahigh reaction rate that is qualified for serving in flow filtration system, completely degrading 100 mg L-1 of 2,4-DCP within 3 s of residence time. Besides, experimental studies confirmed that 1O2 generated by Vo - mediated PDS activation plays the dominate role in the degradation of contaminants. Relative to the previously reported CuO/PDS systems, the obtained CuO1-x nanosheets demonstrated 2.7 times higher specific PDS activity and 67 times higher specific CuO activity for 2,4-DCP removal. Our study not only improves the fundamental understanding of active sites in morphologically tunable metal oxides but also proposes a guideline for future research and engineering application of persulfate.