Single-atom (SA) Fe−N−C catalysts are considered aspromising electrocatalysts for the oxygen reduction reaction (ORR).However, due to the drawbacks of the microporous structure and verystrong binding with O intermediates, Fe−Nx active sites may not alwaysdisplay satisfactory catalytic performance. Therefore, simultaneously en-gineering hierarchical pores and introducing the second metal atom arepromising strategies to break the bottleneck of SA Fe performance. Herein, aneconomical and environmentally friendly method is used to prepare an Fe−Co dual-atom catalyst (DAC) with a microporous/mesoporous coupledstructure (HP/FeCo-NC-2). HP/FeCo-NC-2 effectively enhances the masstransfer process and the ORR activity of Fe−N−C. The atomic dispersion ofthe as-synthesized catalyst was confirmed by synchrotron X-ray absorption spectroscopy. The Brunauer−Emmett−Teller test wasused to assess the number of catalyst-mesoporous structures, and HP/FeCo-NC-2 has a more mesoporous structure than HP/FeCo-NC-1. More mesopores allow faster electrolyte access to the active sites inside the catalyst, facilitating the rate of mass transfer duringthe reaction. Consequently, the structural advantages and interactions between Fe and Co endow HP/FeCo-NC-2 with ORRperformance superior to those of HP/FeCo-NC-1 and HP/Fe-NC-2 in 0.1 M KOH.
