Abstract Scope |
Carbon materials doped with iron (Fe) and nitrogen (N) have recently emerged as novel, efficient electrocatalysts, alternative to precious metals, for promoting oxygen reduction reaction (ORR) occurring at the cathode of polymer electrolyte membrane fuel cells. Here, we employed the first-principles density functional theory calculation method to predict the ORR activity and stability on two types of FeN4 moieties substitutionally embedded into a graphene layer. On each FeN4 active site, we calculated the adsorption energies of all the relevant chemical species, including O2, O, OH, OOH, and H2O, the activation energies for O-O bond scission reaction involved in ORR, and free energy change for the demetallation process of Fe. Our high-throughput computation found that the S1 type FeN4 site was more active than the S2 type FeN4 site to promote ORR, whereas the S2 type FeN4 site was more stable than the S1 type FeN4 site during ORR. |