Towards High‐Performance Electrocatalysts for Oxygen Reduction: Inducing Atomic‐Level Reconstruction of Fe‐Nx Site for Atomically Dispersed Fe/N‐Doped Hierarchically Porous Carbon

Abstract A rational and effective strategy for the synthesis of a high‐performance non‐precious metal electrocatalyst for oxygen reduction reaction (ORR) was developed by inducing reconstruction of Fe‐Nx site on pig‐bone‐derived nitrogen‐doped hierarchically porous carbon. The resultant Fe/N‐doped carbon electrocatalyst possessed abundant atomically dispersed non‐planar Fe‐N4 ORR active sites, with absolute presence of active D1 (FeII‐N4) and D3 (N‐FeII‐N2+2) sites, as well as large specific surface area and three‐dimensional porous structure with hierarchical micro‐/meso‐/macro‐pore distribution, which increased the utilization of active sites and promoted mass transport of ORR reactants. This resulted in a remarkably superior ORR activity with half‐wave potential of 0.87 V (20 mV higher than Pt/C) and kinetic current density of 10.9 mA cm−2 at 0.85 V (2.3‐fold of Pt/C) in alkaline electrolyte. This methodology provides a route for atomic‐level design of high‐performance ORR electrocatalyst.