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Updated: Aug 6, 2025

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction
Published on: April 10, 2018
Regulating the Coordination Geometry and Oxidation State of Single-Atom Fe Sites for Enhanced Oxygen Reduction
Minjie Wang1, Li Wang1, Qingbin Li1
1School of Chemistry and Environmental Engineering, Pingdingshan University, Pingdingshan, 467000, P. R. China.
Abstract:
FeNC catalysts demonstrate remarkable activity and stability for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells and Zn-air batteries (ZABs). The local coordination of Fe single atoms in FeNC catalysts strongly impacts ORR activity. Herein, FeNC catalysts containing Fe single atoms sites with FeN3 , FeN4 , and FeN5 coordinations are synthesized by carbonization of Fe-rich polypyrrole precursors. The FeN5 sites possess a higher Fe oxidation state (+2.62) than the FeN3 (+2.23) and FeN4 (+2.47) sites, and higher ORR activity. Density functional theory calculations verify that the FeN5 coordination optimizes the adsorption and desorption of ORR intermediates, dramatically lowering the energy barrier for OH- desorption in the rate-limiting ORR step. A primary ZAB constructed using the FeNC catalyst with FeN5 sites demonstrates state-of-the-art performance (an open circuit potential of 1.629 V, power density of 159 mW cm-2 ). Results confirm an intimate structure-activity relationship between Fe coordination, Fe oxidation state, and ORR activity in FeNC catalysts.
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