Issue 36, 2023

Spin-dependent active centers in Fe–N–C oxygen reduction catalysts revealed by constant-potential density functional theory

Abstract

Iron and nitrogen co-doped carbon (Fe–N–C) catalysts have shown great promise in promoting the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. Experimental characterization studies, including Mössbauer and X-ray emission spectroscopy, have revealed the crucial role of spin states in Fe–N–C catalysts in ORR catalysis, but comprehensive theoretical understanding in this aspect is still lacking. Herein, using the grand-canonical density functional theory, we systematically investigate the interplay of the oxidation state, spin state, and applied potentials on the catalytic activity of an FeN4C10 moiety. We have identified two stable spin states of Fe(II)N4C10 at ORR-relevant potentials, namely, a high-spin state with out-of-plane Fe displacement and an in-plane intermediate-spin state. Our results show that the FeN4C10 moiety at the two different spin states exhibits distinct abilities to bind ORR intermediates and ORR activities. Our study provides valuable insights into the spin-correlated catalytic performances of Fe–N–C catalysts.

Graphical abstract: Spin-dependent active centers in Fe–N–C oxygen reduction catalysts revealed by constant-potential density functional theory

Supplementary files

Article information

Article type
Paper
Submitted
02 jun 2023
Accepted
27 jul 2023
First published
27 jul 2023

J. Mater. Chem. A, 2023,11, 19360-19373

Spin-dependent active centers in Fe–N–C oxygen reduction catalysts revealed by constant-potential density functional theory

T. Zheng, J. Wang, Z. Xia, G. Wang and Z. Duan, J. Mater. Chem. A, 2023, 11, 19360 DOI: 10.1039/D3TA03271J

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