Boosting the activity of Fe-Nx moieties in Fe-N-C electrocatalysts via phosphorus doping for oxygen reduction reaction

The Fe-N-C material is a promising non-noble-metal electrocatalyst for oxygen reduction reaction (ORR). Further improvement on the ORR activity is highly desired in order to replace Pt/C in acidic media. Herein, we developed a new-type of single-atom Fe-N-C electrocatalyst, in which Fe-Nx active sites were modified by P atoms. The half-wave potential of the optimized material reached 0.858 V, which is 23 mV higher than that of the pristine one in a 0.1 mol L−1 HClO4 solution. Density functional theory (DFT) calculations revealed that P doping can reduce the thermodynamic over potential of the rate determining step and consequently improve the ORR activity.