Heteroatom-doped Co-N-C single-atom catalysts achieve robust peracetic acid activation for sustainable water decontamination.

Peracetic acid (PAA)-based advanced oxidation processes hold great promise in water purification, but how to controllably regulate the composition of reactive species to meet distinct water quality demands remains a considerable challenge. Herein, we report that regulating the electronic structure of isolated Co-N4 sites via heteroatom-doped engineering (with S or P) can significantly boost the contribution of singlet oxygen (1O2) in PAA activation. Theoretical calculations reveal that S/P doping optimized the electronic structure of Co sites to facilitate PAA adsorption, significantly lowering the reaction energy barrier and altering the rate-determining step for 1O2 generation. The S-doped Co single-atom catalysts (CoSA-CNS) exhibited the highest catalytic activity compared to the P-doped CoSA-CNP and undoped CoSA-CN, outperforming most existing heterogeneous activators for PAA and being one of the most efficient Co-based catalysts to date. The strong selectivity for non-radical oxidation equipped the CoSA-CNS/PAA system with more robust performance against the complex water matrices in sulfamethoxazole (SMX). Moreover, the CoSA-CNS/PAA system demonstrated outstanding stability in repeated usage and maintained high performance in continuous-flow microreactors over extended operation. Toxicity assessment further revealed the effective detoxification of sulfamethoxazole and its intermediates, underscoring the system's potential for practical and sustainable water treatment applications.