Interplay of hetero-MN4 catalytic sites on graphene for efficient oxygen reduction reaction

•Bimetallic molecular catalysts supported on graphene is synthesized.•Electrochemical activation promotes dispersion of the catalytic sites.•The composite exhibited high ORR efficiency & stability in neutral medium.•DFT calculations predict a sandwich configuration with correlated electron density.•O2 interaction on a metal site depends on the other neighboring metal in the sandwich.