Theory‐Guided Regulation of FeN₄Spin State by Neighboring Cu Atoms for Enhanced Oxygen Reduction Electrocatalysis in Flexible Metal–Air Batteries

Abstract

Iron, nitrogen‐codoped carbon (Fe−N−C) nanocomposites have emerged as viable electrocatalysts for the oxygen reduction reaction (ORR) due to the formation of FeNxCy coordination moieties. In this study, results from first‐principles calculations show a nearly linear correlation of the energy barriers of key reaction steps with the Fe magnetic moment. Experimentally, when single Cu sites are incorporated into Fe−N−C aerogels (denoted as NCAG/Fe−Cu), the Fe centers exhibit a reduced magnetic moment and markedly enhanced ORR activity within a wide pH range of 0–14. With the NCAG/Fe−Cu nanocomposites used as the cathode catalyst in a neutral/quasi‐solid aluminum–air and alkaline/quasi‐solid zinc–air battery, both achieve a remarkable performance with an ultrahigh open‐circuit voltage of 2.00 and 1.51 V, large power density of 130 and 186 mW cm−2, and good mechanical flexibility, all markedly better than those with commercial Pt/C or Pt/C‐RuO2 catalysts at the cathode.

Charge and spin communication between dual metal single-atom sites on C2N sheets: regulating electronic spin moments of Fe atoms for N2activation and reduction

“…Previous studies on the CO 2 RR and ORR also showed that the adjacent metal atoms on N-doped graphene tuned the electronic spin moments of reactive metal sites, leading to increased intrinsic activity. 18,20 In addition, Mi and Guo et al also highlighted the key role of the magnetic active center in the ORR 43 and the hydrogen evolution reaction (HER). 44…”

“…Previous studies on the CO 2 RR and ORR also showed that the adjacent metal atoms on Ndoped graphene tuned the electronic spin moments of reactive metal sites, leading to increased intrinsic activity. 18,20 In addition, Mi and Guo et al also highlighted the key role of the magnetic active center in the ORR 43 and the hydrogen evolution reaction (HER). 44 Very recently, Ren and Li et al 45 reported the delicate synergetic effect of charge transfer and spin selection of magnetic single Mn atom catalysts conned in graphitic-C 3 N 4 / CeO 2 (111) for CO oxidization.…”

“…Increasing metal loading while maintaining the structure of single atom sites could shorten the separation between individual sites, resulting in formation of neighbors with potential synergetic interaction to boost catalytic activity. 15–18…”

“…Up to now, several experimental studies have been devoted to exploring the effect of adjacent metal sites on the catalytic performance of SACs for the oxygen reduction reaction (ORR) 17,18 and carbon dioxide reduction reaction (CO 2 RR). 15,19 Recently, a pioneering study by Jin and Yu et al emphasized the significance of the inter-site distance effect in Fe–N 4 SACs for the ORR.…”

“…Increasing metal loading while maintaining the structure of single atom sites could shorten the separation between individual sites, resulting in formation of neighbors with potential synergetic interaction to boost catalytic activity. [15][16][17][18] Up to now, several experimental studies have been devoted to exploring the effect of adjacent metal sites on the catalytic performance of SACs for the oxygen reduction reaction (ORR) 17,18 and carbon dioxide reduction reaction (CO 2 RR). 15,19 Recently, a pioneering study by Jin and Yu et al emphasized the signicance of the inter-site distance effect in Fe-N 4 SACs for the ORR.…”