▎ 摘　　要

NOVELTY - Carbon black, graphene and oxygen-doped graphene is used in preparing catalyst for electrocatalytic production of hydrogen peroxide. USE - Carbon black, graphene and oxygen-doped graphene used in preparing catalyst for electrocatalytic production of hydrogen peroxide (claimed). ADVANTAGE - The obtained air cathode has simple structure without complex operation, and can be operated at low potential. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) air cathode comprising diffusion layer, catalyst layer containing obtained catalyst, and collector layer, where the collector layer and catalyst layer are set on similar side of diffusion layer; (2) preparation of air cathode comprising placing diffusion layer on one side of collector layer, and placing catalyst layer on one side of collecting layer away from diffusion layer; and (3) sewage treatment system comprising housing having reaction space, anode set in reaction space and attached with electrogenic microorganism, and air cathode set in reaction space.