Self-reconstruction of single copper atoms drives precise hydroxyl radicals generation for efficient water disinfection.

Antibiotic-resistant bacteria (ARB) and their genes (ARGs) pose a significant risk to public health and the ecosystem. Conventional water disinfection efficiently eliminates pathogens, however, it requires intensive chemical consumption but inefficiently removes ARGs. Herein, we propose an on-demand electrochemical platform that simultaneously eliminate both ARB and ARGs with in-situ generated hydroxyl radicals (·OH) without additional chemical inputs. Single-atom copper catalysts with CuN4 coordination structure (SA-CuN4/NC) are precisely tuned to directly convert oxygen into controllable ·OH via three-electron oxygen reduction reaction (3e⁻ ORR). Operando X-ray adsorption near-edge spectroscopy reveals a potential-driven self-reconstruction of single-atom Cu sites to optimize ·OH concentration. Specially, the preferentially adsorbed H+ onto the adjacent N atoms promotes the breaking of Cu-N bonds to form stable Cu2-CuN2 cluster as a genuine active site. As expected, the SA-CuN4/NC with moderate ·OH (~11.5 μM) exhibits ultra-fast degradation of E. coli HT115, accomplishing an ~ 8 log removal within 1 min and a complete elimination of ARGs in 30 min. Excess ·OH (~47.9 μM) triggers bacterial aggregation which compromises bacterial inactivation. These findings demonstrate that 3e⁻ ORR is a sustainable and effective strategy to obtain fast and complete water disinfection, preventing environmental spread of ARGs.