Because of the limited characterization methods of the structures and morphology of N-doped carbocatalysts that are available at the atomic level, the detailed promotion mechanism of the catalytic efficiency is unspecific and the particular active sites introduced by the N atoms require further evaluation. Herein, this challenging issue is tackled by extensive theoretical simulation. It is first proposed that the active sites, wherein O2 molecules become adsorbed and activated, be tailored by synergistic graphitic and pyridinic N atoms (GrN and PyN, respectively), which remarkably accelerate the generation of highly chemically reactive O-containing species. The boosted catalytic efficiency is essentially contributed by the electron donor and acceptor of the two active sites, which are induced by PyN and GrN, respectively. These active sites steer the electron transfer between O2 molecules, and the reaction centers in a one-way transmission manner along the PyN → O1 → O2 → C → GrN path. This work provides a feasible protocol for the modification of generally practical carbocatalysts and sheds new light on the understanding of the catalysis mechanism.
Keywords: AIMD; DFT; N doping; NEB; O2 activation; active site; carbocatalyst; reaction rate.