Towards High‐Performance Electrocatalysts for Oxygen Reduction: Inducing Atomic‐Level Reconstruction of Fe‐N_x 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-N site on pig-bone-derived nitrogen-doped hierarchically porous carbon. The resultant Fe/N-doped carbon electrocatalyst possessed abundant atomically dispersed non-planar Fe-N ORR active sites, with absolute presence of active D1 (Fe -N ) and D3 (N-Fe -N ) 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 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.

Porous Carbons Derived from Collagen‐Enriched Biomass: Tailored Design, Synthesis, and Application in Electrochemical Energy Storage and Conversion

“…When used as a catalyst for ORR, Co‐N‐C outperformed commercial Pt/C in terms of catalytic activity (with a half‐wave potential of 0.835 V), operating stability, and fuel selectivity. To further improve the catalytic activity of TM‐N‐C, they also prepared an Fe‐N‐C catalyst by pyrolyzing a pig bone‐derived porous carbon network with 5,10,15,20‐tetrakis(4‐phenyl)‐porphyrin iron(III) chloride . In contrast to the synthesis of the Co‐N‐C catalyst, the pyrolyzed products were further treated by acid‐washing and a second heat treatment to tune the Fe‐N moieties at an atomic level.…”

A pyridinic Fe-N4 macrocycle models the active sites in Fe/N-doped carbon electrocatalysts

“…Based on the aggregate spectroscopic evidence on Fe-N-C materials, we envisioned that an improved model complex would feature: (a) a tetrapyridinic coordination environment, (b) relatively short Fe–N bond lengths 17 , (c) an extended ligand π system 29 , 30 capable of stabilizing the Fe(II) state 43 , 44 , and (d) a relatively high Fe(III)-OH/Fe(II)-OH 2 redox potential. Towards realizing the above goal of synthesizing a pyridinic Fe-N 4 model complex, we searched the literature for pyridinic N 4 macrocyclic ligands.…”

From energetic cobalt pentazolate to cobalt@nitrogen-doped carbons as efficient electrocatalysts for oxygen reduction

“…3b and Fig. S12) [34], which exhibited that the carbon was bonded to nitrogen and surrounding oxygen species. The high-resolution N 1s spectra were curve-fitted into four individual peaks: pyridinic N (398.4 eV), pyrrolic N/Co −N (400.3 eV), graphitic N (401.2 eV) and oxidized N (403.6 eV) (Fig.…”