Activity and Stability of Single- and Di-atom catalysts for O₂ reduction reaction

Efficient and in-expensive catalysts for the O₂ reduction reaction (ORR) is needed for advancement of renewable energy technologies. In this study, we design a computational catalyst screening method to identify single and di-atom metal dopants from first-row transition elements supported on defected nitrogenated graphene surfaces for ORR. Based upon the formation energy calculations and micro-kinetic modelling of reaction pathways using the intermediate binding free energies, we have identified four potentially interesting SACs and fifteen DACs with relatively high estimated catalytic activity at 0.8 V vs RHE. Among the best SACs, MnNC shows high stability in both acidic and alkaline media according to our model. For the DACs, we found four possible candidates as MnMn, FeFe, CoCo and MnNi doped on quad-atom vacancy sites having considerable stability over a wide pH range. The remaining SACs and DACs with high activity are either less stable or show a stability region at an alkaline pH.