The identification of reactive species in peroxymonosulfate (PMS) activation triggered by carbon-based single atom catalysts is the key to reveal the pollutant degradation mechanism. Herein, carbon-based single atom catalyst with low-coordinated Co-N₃ sites (Co_SA-N₃-C) was synthesized to active PMS for norfloxacin (NOR) degradation. The Co_SA-N₃-C/PMS system exhibited consistent high performance for oxidizing NOR over a wide pH range (3.0–11.0). The system also achieved complete NOR degradation in different water matrixes, high cycle stability and excellent degradation performance for other pollutants. Theoretical calculations confirmed that the catalytic activity was derived from the favorable electron density of low-coordinated Co-N₃ configuration, which was more conductive to PMS activation than other configurations. Electron paramagnetic resonance spectra, in-situ Raman analysis, solvent exchange (H₂O to D₂O), salt bridge and quenching experiments concluded that high-valent cobalt(IV)-oxo species (56.75%) and electron transfer (41.22%) contributed dominantly to NOR degradation. Moreover, ¹O₂ was generated in the activation process while not involved in pollutant degradation. This research demonstrates the specific contributions of nonradicals in PMS activation over Co-N₃ sites for pollutant degradation. It also offers updated perceptions for rational design of carbon-based single atom catalysts with appropriate coordination structure.

识别由碳基单原子催化剂引发的过氧单硫酸盐（PMS）活化中的活性物质是揭示污染物降解机理的关键。在此，合成了具有低配位 Co-N ₃位点 (Co _SA -N _{3 -C) 的碳基单原子催化剂，用于活性 PMS 以降解诺氟沙星 (NOR)。}Co _SA -N ₃-C/PMS 系统在较宽的 pH 范围 (3.0–11.0) 内表现出一致的氧化 NOR 的高性能。该系统还实现了NOR在不同水基质中的完全降解、高循环稳定性和对其他污染物的优异降解性能。理论计算证实，催化活性源自低配位Co-N ₃构型的有利电子密度，其比其他构型更有助于PMS活化。电子顺磁共振光谱、原位拉曼分析、溶剂交换（H ₂ O 到 D ₂ O）、盐桥和淬火实验得出高价钴（IV）-氧代物种（56.75%）和电子转移（41.22%） ) 对 NOR 降解起主要作用。而且，¹ O ₂在活化过程中产生，不参与污染物降解。_{这项研究证明了非自由基在 PMS 活化中对 Co-N 3 位}点污染物降解的具体贡献。它还为合理设计具有适当配位结构的碳基单原子催化剂提供了最新的认识。