Superior efficiency hydrogen peroxide production in acidic media through epoxy group adjacent to Co-O/C active centers on carbon black

•A facile strategy to construct a similar coordination environment around the metal atom center using CB particles as substrates;•Both a high yield rate of 110.2 mmol gmetal−1 h−1 at the potential of 0.3 V vs RHE and a high positive onset potential of 0.65 V vs RHE were achieved.•The active center was revealed for 2e−-ORR, including the Co-C3O1 moiety as the first coordination and the epoxy group at ⑥ site in the second coordination sphere.•The practical application of CB-based SACs was evaluated in a wastewater treatment system including an H2O2 electrolyzer and a Fenton filter.