Comparative Study of Oxygen Reduction Reaction Mechanism on Nitrogen-, Phosphorus-, and Boron-Doped Graphene Surfaces for Fuel Cell Applications

X-doped graphene surfaces, where X is a heteroatom, are interesting for electrocatalytic applications in fuel cells because active sites are generated on the surface because of the presence of these heteroatoms. In this work, a comparative study of the oxygen reduction reaction (ORR) on three graphene surfaces doped with nitrogen, boron, and phosphorus was made by using density functional theory. Our simulation reveals that the ORR via a four-electron transfer mechanism is energetically more favorable than the two-electron transfer mechanism, where the latter pathway would lead to the unwanted oxygen peroxide formation. In addition, the energies calculated for each ORR step show that the P-doped surface is the one that favors the oxygen reduction reaction the most.