Regulating the Electronic Structure of Cu Single-Atom Catalysts toward Enhanced Electro-Fenton Degradation of Organic Contaminants via O and OH.

Heterogeneous electro-Fenton degradation with O and OH generated from O reduction is cost-effective for the removal of refractory organic pollutants from wastewater. As O is more tolerant to background constituents such as salt ions and a high pH value than OH, tuning the production of O and OH is important for efficient electro-Fenton degradation. However, it remains a great challenge to selectively produce O and improve the species yield. Herein, the electronic structure of atomically dispersed Cu-N sites was regulated by doping electron-deficient B into porous hollow carbon microspheres (CuBN-HCMs), which improved *O adsorption and significantly enhanced O selectivity in electro-Fenton degradation. Its O yield was 2.3 times higher than that of a Cu single-atom catalyst without B doping. Meanwhile, OH was simultaneously generated as a minor species. The CuBN-HCMs were efficient for the electro-Fenton degradation of phenol, sulfamethoxazole, and bisphenol A with a high mineralization efficiency. Its kinetic constants showed insignificant changes under various anions and a wide pH range of 1-9. More importantly, it was energy-efficient for treating actual coking wastewater with a low energy consumption of 19.0 kWh kg. The superior performance of the CuBN-HCMs was contributed from O and OH and its high O selectivity.