Electrocatalytic Activity and Design Principles of Heteroatom-Doped Graphene Catalysts for Oxygen-Reduction Reaction

Heteroatom-doped graphene materials have emerged as highly efficient and inexpensive and variations of graphene doping structures; however, there is still a lack of fundamental understanding of the trend and mechanisms in their ORR activity, which greatly hinders the development of highly active graphene-based catalysts. Here we use density-functional calculations to study the ORR activity and mechanism of nonmetal-element doped graphene catalysts with different doping configurations. Our results demonstrate that binding energies of ORR intermediates (i.e., *OH) on the catalysts can serve as a good descriptor for the ORR activity, attaining the optimal value at the vicinity of ∼2.6 eV. The analysis of electronic structures indicates that the ORR activity of doped graphene catalysts depends on the abundance of electronic states at the Fermi level, which dominates the charge transfer between ORR intermediates and the catalysts. Using binding energy as a descriptor, we predict the realization of highly active graphene-based electrocatalysts by the dual-doping scheme, which is supported by recent experimental reports. Moreover, we find that the catalytic activity of graphene basal planes can be activated by the B–Sb and B–N codoping approaches. This work elucidates the inherent correlation between the ORR activity of nonmetal-doped graphene catalysts and the dopant type and doping configurations, opening a route to design highly active graphene-based ORR electrocatalysts.