Efficient electrocatalysts of single metal atom supported on defective graphene for oxygen reduction reaction (ORR): A first principles study

Recently, single Pt atom doped on graphene divacancy defect was fabricated and showed excellent oxygen reduction reaction (ORR) activity and durability. Here, we choose it as benchmark to search for comparable or even better catalyst, density functional calculation is performed to explore the possibility of five single 3d transition metals (Mn, Fe, Co, Ni, Cu) doped on defective graphene for ORR. The corresponding stabilities and ORR activities are investigated. The results show that purely defective graphene can act as substrate to stabilize the selected 5 single transition metals. The adsorption free energies of the reaction intermediates scale with each other and based on which the activity volcano map is obtained. Among all structures, the Ni atom doped on the divacancy graphene exhibits the lowest theoretical overpotential, even better than that of the experimentally available Pt single atoms doped on divacancy graphene.