在Ni沉积的石墨表面氧吸附和还原的反应机理第一性密度泛函理论研究

Abstract

Nitrogen doped graphene （N-graphene）has been reproted possessing significant oxygen reduction reaction （ORP）activity in recent years. However, how the activity depended on the distribution condiguration of nitrogen and doping concentration are still ambigugous, and the ORP mechanism on N-graphene and the rate-determaing steps are figured out. The adsorption energy of Oads species on the surface in contrast with that on Pt can be used to approximately describe the ORP activity.Using density functional calculationas (VASP),We find that on N-graphene with 9%~20% doping concentration the dissociation adsorption energy of dioxygen is comparable with that on Pt. The change atom and the adsorption energy in variation with N concentration is dominated by the electrostatic force between the oxygen atom and the adsorption-site carbon atom. Too low (20%)nitrogen concentration will depress the electrostatic force of C-O adsorption bond and weaken the adsorption because the oxygen atom will withdraw fewer electrons from the surface