Single-Atom Cobalt Catalysts for Electrocatalytic Hydrodechlorination and Oxygen Reduction Reaction for the Degradation of Chlorinated Organic Compounds

Electrochemical reduction-oxidation processes with the aid of cathode catalysts are promising technologies for the decomposition of organic compounds. High-efficiency and low-cost catalysts for electrochemical reductive dechlorination and two-electron oxygen reduction reaction (ORR) are vital to the overall degradation of chlorinated organic compounds. This study reports electrochemical dechlorination using a single-atom Co-loaded sulfide graphene (Co-SG) catalyst via atomic hydrogen generated from the electrochemical reduction of H₂O and electrolysis of hydrogen. The Co-SG electrocatalyst exhibited a remarkable performance for H₂O₂ synthesis with a half-wave potential of 0.70 V (vs RHE) and selectivity over 90%. The high electrochemical performance was achieved for bifunctional electrocatalysis with regard to the smaller overpotentials, faster kinetics, and higher cycling stability compared to the noble metal-based electrocatalysts. In this study, 2,4-dichlorobenzoic acid was well degraded and the TOC concentration was effectively reduced. This work introduces the preparation of a new active site for high-performance single-atom catalysts and also promotes its application in the electrochemical degradation of chlorinated organic pollutants.