Influence of coordination structure of Fe-585DV/NxC4−x on the electrocatalytic performance of oxygen reduction reactions

Abstract

Fe–N–C material, known for its high efficiency, cost-effectiveness, and environmental friendliness, is a promising electrocatalyst in the field of the oxygen reduction reaction (ORR). However, the influence of defects and coordination structures on the catalytic performance of Fe–N–C has not been completely elucidated. In our present investigation, based on density functional theory, we take an Fe adsorbed graphene structure containing a 5–8–5 divacancy (585DV) defect as a research model and investigate the influence of the coordination number of N atoms around Fe (Fe–N_xC_(4−x)) on the ORR electrocatalyst behavior in alkaline conditions. We find that the Fe–N₄ structure exhibits superior ORR catalytic performance than other N coordination structures Fe–N_xC_4−x (x = 0–3). We explore the reasons for the improved catalytic performance through electronic structure analysis and find that as the N coordination number in the Fe–N_xC_(4−x) structure increases, the magnetic moment of the Fe single atom decreases. This reduction is conducive to the ORR catalytic performance, indicating that a lower magnetic moment is more favorable for the catalytic process of the ORR within the Fe–N_xC_(4−x) structure. This study is of great significance for a deeper understanding of the structure–performance relationship in catalysis, as well as for the development of efficient ORR catalysts.