Investigation of two-electron ORR pathway of non-metallic carbon-based catalysts with P-C bond structure in Cl--bearing electrolytes

On-site small-scale synthesis of H2O2 using an electrocatalytic reaction with seawater and air as feedstock is crucial for the Fenton reaction to handle marine pollution. However, the reaction is severely constrained by the poisonous effects of excess Cl- in seawater on the 2e- oxygen reduction reaction (ORR) center, necessitating the development of catalysts with high activity and chlorine tolerance. In this study, a catalyst with a high H2O2 yield of 3.33 molg−1h−1 was developed with P-C bond structures whose active center was not only unaffected by Cl- but also promoted the reduction of O2 to H2O2 in the 2e- path when adsorbed Cl- was present. The H2O2 produced in real seawater completely inactivated the algal microorganisms in the flow cell within 10 min. Our results could advance technologies for reducing marine pollution and serve as a guide for the design of catalysts used in Cl--bearing electrolytes.