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  • Theoretical Investigation o...
    Pham, Nguyet N. T; Kim, Kwang Ho; Han, Byungchan; Lee, Seung Geol

    Journal of physical chemistry. C, 04/2022, Volume: 126, Issue: 13
    Journal Article

    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.