Novel catalytic activity for oxygen reduction reaction on MnN4 embedded graphene: A dispersion-corrected density functional theory study

Metal-coordinated nitrogen-doped graphene is attractive for its application in oxygen reduction reaction (ORR) at the cathode of hydrogen fuel cells. The detailed paths of ORR on MnN4 embedded graphene (MnN4-gra) have been investigated by using the dispersion-corrected density functional theory (DFT-D) method. It is found that the MnN4-gra can be stable at high temperature from the first-principles molecular dynamics simulation and the MnN4 is the active center for all the possible elementary steps of the ORR. Both the four-electron OOH dissociation and the O2 direct dissociation paths are probable for ORR on the MnN4-gra, which are followed by the two OH's path or the OH hydrogenation into H2O path. All the proposed paths for the ORR on the MnN4-gra are exothermic with small reaction barriers (17.3 kcal/mol or smaller) to go through the rate-limiting steps. The MnN4-gra may have novel catalytic activity for ORR, which is comparable to that of the Pt catalyst.