Activation of peroxymonosulfate by single atom Co-N-C catalysts for high-efficient removal of chloroquine phosphate via non-radical pathways: Electron-transfer mechanism.

• Co-N-C SACs with Co-N x sites was successfully synthesized by facile method. • SA Co-N-C(30) exhibited an excellent catalytic performance for PMS activation. • Experiments and DFT calculations demonstrated Co-N 3 was optimum active site. • The electron-transfer was regarded as the dominated reactive pathway for CQP degradation. Chloroquine phosphate (CQP) has played a role in the remission of COVID-19, but its large use will undoubtedly pollute the water. Herein, we have designed biomass carbon-based catalysts with anchoring sites for single cobalt atoms in a defined Co-N 3 coordination structure (SA Co-N-C(30)). A peroxymonosulfate (PMS) activation system employing the SA Co-N-C(30) as a high-efficiency catalyst was demonstrated, which can efficiently degrade CQP in a wide pH range (3–11). The electron-transfer was proposed as the dominant non-radical pathway for CQP degradation in SA Co-N-C(30)/PMS system by electrochemical studies and quenching experiments, and the generated singlet oxygen (1O 2) played a negligible role. The density functional theory (DFT) calculations and experimental results showed that Co-N 3 site served as the main active site for PMS activation. In addition, SA Co-N-C(30)/PMS system had excellent efficiencies in oxidative degradation of various organic pollutants. This work opens up a new avenue to efficient degradation of organic pollutants. [ABSTRACT FROM AUTHOR]