Electrochemical advanced oxidation processes (EAOPs) show great potential to scale across centralized and distributed treatment contexts and thus already have detailed mechanism studies and practical applications, such as the electro-oxidation and electro-Fenton techniques. However, peroxymonosulfate-based EAOPs (PMS-EAOPs), as an emerging electrochemical system in wastewater treatment, still lack the corresponding mechanisms research, particularly in terms of the deep understanding of electro-enhanced PMS activation. Herein, to establish an ideal platform for performance enhancement and mechanistic investigation of electrochemical PMS activation, we developed a self-supported single-atom cobalt electrode that couples catalytic active sites with excellent mass transfer to fully unleash its intrinsic activity. It is found that the anode electric field can create a PMS-enriched interface microenvironment, delivering a 26.6-fold activity enhancement relative to the cathodic counterpart. Meanwhile, electric field-induced electron delocalization at the cobalt site facilitates electron transfer with PMS. This dual synergistic modulation collectively lowers the physical and energetic barriers for PMS activation, achieving 100% sulfamethoxazole removal within 2 min while reducing oxidant dosage by 80-90% relative to other reported PMS-EAOP systems. This study establishes a mechanistic framework for electric field-modulated Fenton-like catalysis, highlighting the critical roles of interfacial microenvironment and electronic structure, and advances the design of PMS-based EAOPs and related electrocatalytic applications.
Liang et al. (Mon,) studied this question.