Issue 27, 2014

A density functional theory study of oxygen reduction reaction on non-PGM Fe–Nx–C electrocatalysts

Abstract

First-principles density functional theory (DFT) calculations were performed to explain the stability of catalytically active sites in Fe–Nx–C electrocatalysts, their ORR activity and ORR mechanism. The results show that the formation of graphitic in-plane Fe–N4 sites in a carbon matrix is energetically favorable over the formation of Fe–N2 sites. Chemisorption of ORR species O2, O, OH, OOH, and H2O and O–O bond breaking in peroxide occur on both Fe–N2 and Fe–N4 sites. In addition to the favorable interaction of ORR species, the computed free energy diagrams show that elementary ORR reaction steps on Fe–Nx sites are downhill. Thus, a complete ORR is predicted to occur via a single site 4e mechanism on graphitic Fe–Nx (x = 2, 4) sites. Because of their higher stability and working potential for ORR, Fe–N4 sites are predicted to be prime candidate sites for ORR in pyrolyzed Fe–Nx–C electrocatalysts.

Graphical abstract: A density functional theory study of oxygen reduction reaction on non-PGM Fe–Nx–C electrocatalysts

Supplementary files

Article information

Article type
Paper
Submitted
16 huhti 2014
Accepted
15 touko 2014
First published
15 touko 2014

Phys. Chem. Chem. Phys., 2014,16, 13800-13806

A density functional theory study of oxygen reduction reaction on non-PGM Fe–Nx–C electrocatalysts

S. Kattel, P. Atanassov and B. Kiefer, Phys. Chem. Chem. Phys., 2014, 16, 13800 DOI: 10.1039/C4CP01634C

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