Engineering Geometric Asymmetry in Co─N <sub>4</sub> Sites by Chlorination Coordination for Enhanced Peroxymonosulfate Activation
Huanran Miao, Xiai Zhang, Xinwei Zhang, Zhongshuang Xu, Qikui Fan, Zhimao Yang, Shuai Wang, Chuncai Kong
Abstract
Abstract Breaking the geometric symmetry of metal–N 4 moieties represents an effective strategy to modulate the electronic environment of single‐atom catalysts (SACs) for enhanced peroxymonosulfate (PMS) activation. Herein, a chlorine‐engineered cobalt SAC (Co/Cl/AC) is constructed by covalently bonding Cl atoms to the carbon matrix adjacent to Co─N 4 sites. The introduced asymmetry redistributes local charge density and downshifts the Co d‐band center, thereby facilitating PMS adsorption and promoting a non‐radical 1 O 2 generation pathway. As a result, Co/Cl/AC achieves superior catalytic performance for volatile organic compounds (VOCs) degradation, with 97.9% toluene removal and ≈80% CO 2 mineralization. Experimental results and DFT calculations reveal that Cl coordination enhances electron transfer, strengthens Co─N interactions, and lowers the energy barrier for PMS decomposition. This work provides mechanistic insights into halogen‐induced symmetry breaking and demonstrates a rational design strategy for constructing high‐performance SACs in advanced oxidation processes.