Theoretical study on the origin of activity for the oxygen reduction reaction of metal-doped two-dimensional boron nitride materials.

Abstract

Two-dimensional boron nitride (2D-BN) materials doped with metallic atoms are suitable candidates for the oxygen reduction reaction (ORR) to replace Pt-based catalysts. In this study, a series of model 2D-BN materials doped with metallic atoms were designed to uncover the relationship between ORR activity and metallic dopants. A volcano curve correlation was derived between ORR overpotential and the adsorption free energy values of *OH. Only the doped structures, located at the top of the volcano curve, exhibit optimized activity. Through analyzing the dynamic results, the ORR was found to occur only via the 4e- pathway on Co doped 2D-BN materials with the activation energy of 0.30 eV, which is lower than that achieved with the state-of-the-art Pt-based catalysts (0.79 eV). Furthermore, based on the calculations of electronic structure properties, we find that the small highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap is more beneficial to the 4e- pathway and prove that the binding strength between metallic atoms-doped 2D-BN materials and oxygenated intermediates is regulated by the HOMO of the metallic dopant consisting non-bonding or delocalized orbitals. These results provide an effective method to facilitate the design of new BN-based materials with high electrocatalytic performances besides the ORR performance.