First-Principles Investigation of the Stability and CH4 Activation Capability of Defective h-BN

Hexagonal boron nitride (h-BN) has been widely applied in catalysis. Nevertheless, most research has focused on using h-BN as a substrate to anchor active transition metals, without probing the intrinsic activity of h-BN vacancies. In this work, we investigated the stability and catalytic activity of different h-BN vacancies. We found that B-terminated vacancies are more likely to be exposed under static conditions. The Nv, BN2, and BN3 vacancies show intermediate reaction energies for CH4 activation. Although the B–N pair over the BN2 vacancy model has the lowest barrier for CH4 activation, the negative reaction energy could lead to a high potential for surface poisoning. Interestingly, the unsaturated B–B pair over Nv is a promising site for C–H bond activation. Further COHP analysis implies that the high C–H bond homolytic cleavage activity of the B–B pair arises from its relatively weak interaction, which can promote H insertion.