Enhancement mechanism of P dopant on atomically distributed FeN4P-C electrocatalyst over a wide pH range

Journal article, 2022

Heteroatom doping plays an essential role in improving the catalytic performance of electrocatalysts for oxygen reduction reaction (ORR). However, how to regulate heteroatom doping remains a significant challenge. This paper develops an efficient strategy by using a novel versatile chelating ligand to enhance P loading and expose more metal single Fe atom active sites of FeN4P-C catalyst. The electron distribution of active center is considerably changed by P doping, which significantly influences the catalytic ORR performance. The dopant P in the FeN4P-C catalyst induces a small number of d-electrons from t2g-orbitals around the Fermi level, making the interaction between Fe active site and O2 slightly more robust than in the FeN4[sbnd]C catalyst, as studied by DFT calculations. The as-prepared FeN4P-C catalyst exhibits excellent catalytic ORR activity in both acidic (with a half-wave potential of 0.760 V vs. RHE) and basic (with a half-wave potential of 0.885 V vs. RHE) conditions, which are superior to those of the commercial Pt/C (20 wt%) catalyst. Furthermore, this catalyst also demonstrates outstanding stability and good hydrogen peroxide and methanol tolerance. A Zinc-air battery(ZAB) assembled using the cathode catalyst has validated the high performance of this catalyst. This study provides an efficient method for generating well-defined single-atom active sites to improve catalytic performance and paves the way to identify coordinated single metal atom sites for electrocatalysis applications.