Electrocatalysis is increasingly important in water treatment for its efficiency and eco-friendliness, and materials play important role in performance. In this work, we synthesized an efficient single-atom Co-N/C catalyst for electrocatalytic dehalogenation, which provided more active sites and a faster charge transfer rate. Co-N/C effectively removed florfenicol (FLO) over a broad pH range, with rate constants that were 3.5 and 2.1 times higher than those of N/C and commercial Pd/C, respectively. The defluorination and dechlorination efficiencies were 67.6 and 95.6%, respectively, with extremely low Co leaching (6 μg L^-1) and low energy consumption (22.7 kWh kg^-1). H* and direct electron transfer were the primary causes of dehalogenation. The Co-N/C was minimally affected by pH, co-existing ions, and water quality, maintaining a high removal rate (>90%) after ten cycles [1]. To enhance H* production, the phosphorus-doped cobalt nitrogen carbon catalyst (Co-NP/C) was prepared for electrocatalytic dechlorination, which had high catalytic activity in a wide pH range (3-11). The introduction of phosphorus was found enhanced the electron density of cobalt and regulated the electron transfer.

We further developed the heterogeneous electro-Fenton process based on dual-functional cathodes. The catalyst composed of nitrogen-doped carbon nanotubes encapsulating zero-valent iron (Fe@N-C) was synthesized, which demonstrated superior degradation of sulfamethazine (SMT) under mildly alkaline conditions. The primary reactive species generated by Fe@N-C were H* and singlet oxygen (¹O₂), with hydroxyl radicals (∙OH) playing a supportive role [2]. Additionally, the catalyst with boron and nitrogen co-doped carbon nanotubes encapsulating zero-valent iron (Fe@BN-C) was fabricated, which significantly increased the selectivity for H₂O₂ to 94%, and H₂O₂ was directionally converted to ¹O₂ via surface ∙OH. Theoretical calculations confirmed the confinement effect of Fe⁰ overcame the rate-limiting step for H₂O₂ formation, achieving high efficiency and selectivity for ¹O₂ transformation[3].

Traditional free radicals-dominated electrochemical advanced oxidation processes (EAOPs) and sulfate radical-based advanced oxidation processes (SR-AOPs) are limited by pH dependence and weak reusability, respectively. To address these shortcomings, electro-enhanced activation of peroxymonosulfate (PMS) was proposed. Firstly, a novel perovskite-Ti₄O₇ composite anode activating PMS (E-PTi-PMS) system achieved an ultra-efficient removal rate (k = 0.467 min^-1) of carbamazepine (CBZ). The electric field expedited the decomposition and utilization of PMS, promoting the generation of radicals and expanding the formation pathway of ¹O₂. This system presented superiorities over wide pH (3-10) and less dosage of PMS (1 mM), expanding the pH adaptability and reducing the cost of EAOPs [4].