Transforming Plastics to Single Atom Catalysts for Peroxymonosulfate Activation: Axial Chloride Coordination Intensified Electron Transfer Pathway

Abstract Transforming plastics into single‐atom catalysts is a promising strategy for upcycling waste plastics into value‐added functional materials. Herein, a graphene‐based single‐atom catalyst with atomically dispersed FeN₄Cl sites (Fe─N/Cl─C) is produced from high‐density polyethylene wastes via one‐pot catalytic pyrolysis. The Fe─N/Cl─C catalyst exhibited much higher turnover frequency and surface area normalized activity (K_ac) compared with the Fe─N─C catalyst without axial Cl modulation. Both experiments and density functional theory (DFT) computations demonstrated that the axial incorporation of chloride fine‐tuned the coordination environment of FeN₄ sites and enhanced peroxymonosulfate (PMS) activation because of improved conductivity and modulated spin state. In situ, Raman, and infrared spectroscopic techniques revealed that PMS is activated by the Fe─N/Cl─C catalyst through an electron transfer process. The formation of a key PMS^* intermediate at the Fe site effectively elevated the redox capacity of the catalyst surface to realize a fast degradation of diverse pollutants. The non‐radical oxidation manner secures high selectivity toward target pollutants and high chemical utilization efficiency. A continuous operation in a column reactor also demonstrated the high efficiency and stability of the (Fe─N/Cl─C + PMS) system for practical water treatment.