Journal Article graphene quantum dots CO2 electroreduction methane oxygen reduction reaction 2 e− electrocatalysis 2D carbon nitride 2H and 1T′ phase B, N doping CO2 reduction Cu single‐atom catalysts MoS2 N-B-OH sites Review amine functionalization amorphous carbon amphiphilic aromatic N-heterocycles bandgap basal-plane and edge active sites carbon carbon-based electrocatalyst catalysis chemical vapor deposition cooperative catalysis copolymers e-beam lithography energy storage functionalization graphene