P-doped nanomesh graphene with high-surface-area as an efficient metal-free catalyst for aerobic oxidative coupling of amines

Abstract

Phosphorus-doped nanomesh graphene (PG) with huge specific surface area and lamellar hexagonal structure has been synthesized by a thermal annealing method using MgO as a template and triphenylphosphine (TPP) as both phosphorus and carbon source. The synthesized PG with a high phosphorous content of 1.61 at% is found to exhibit efficient metal-free heterogeneous catalytic activity for aerobic oxidative coupling of amines catalysts under mild and neat conditions using molecular oxygen as the oxidant. Moreover, our results indicate that the phosphorus doping is more efficient to promote the catalytic activity than that of nitrogen doping in aerobic oxidative coupling of amines. Based on the results of density function theory (DFT) calculations, it is found that phosphorus incorporated into the graphene matrix exhibit the highest catalytic activity due to its lowest adsorption energy of benzylamine and longest elongation of OO bonds.