Single Cobalt Atom Catalyst for Electrocatalytic Hydrodechlorination and Oxygen Reduction Reaction for Degradation of Chlorinated Organic Compounds.

Electrochemical reduction-oxidation processes in aid of cathode catalysts are promising technologies used 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 the 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. Co-SG electrocatalyst exhibited a remarkable performance for H2O2 synthesis with half-wave potential 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 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 to the electrochemical degradation of chlorinated organic pollutants.