Density
functional theory was used to investigate the electrocatalytic
activity of graphitic, edge, and in-plane defects in pyridinic-N doped
on single-layer graphene (SLG) and bilayer graphene (BLG) for the
oxygen reduction reaction (ORR) in alkaline media. The N-doped BLG
exhibited better ORR activity than the N-doped SLG. Graphitic-N-doped
multilayer graphene promoted the 4e– associative
ORR mechanism, where OOH* formation was the rate-determining step.
The intermediate species of the ORR (OOH*, O*, and OH*) were more
strongly bound to the N-doped Bernal BLG structures than to N-doped
SLG because of the interlayer covalent π–π bonding
between the graphene layers in the former. Bernal stacking of the
BLG can improve the stability and ORR activity of graphitic, edge,
and in-plane N-defects, where the rate-determining step of the ORR
is the same as that in the N-doped graphene monolayer. The overpotential
of the BLG with pyridinic-N doped on the edge was 0.570 V, which is
nearly identical to that of Pt(111) in alkaline sodium. Therefore,
the edge pyridinic-N-doped Bernal BLG may be a promising electrocatalyst
for the ORR in polymer electrolyte membrane fuel cells.