Highly efficient Fe-N-C oxygen reduction electrocatalyst engineered by sintering atmosphere

Fe-N and pyridinic-N generally are considered the active sites of Fe-N-C catalyst. In this featured work, small uniform Fe/N-rich polymer spheres are selected to prepare the Fe-N-C catalyst and study how the sintering atmosphere (NH3, Ar, and H-2) to engineer their products. The findings reveal that the sintering atmosphere greatly affected not only the composition, aggregate state, and morphology of Fe, but also the graphitization degree and pore structure of carbon. In addition, XPS results suggest that Fe-N-C-NH3 possesses the highest Fe-N and pyridinic-N content. Combining its abundant pores, high graphitization, and large specific surface area, the catalyst obtained in NH3 atmosphere delivers best ORR catalytic performance (E-0 = 0.97 V, E-1/2 = 0.85 V vs RHE), which is even comparable to commercial Pt/C (E-0 = 0.97 V, E-1/2 = 0.83V vs RHE). Moreover, the catalyst exhibits greater stability and methanol resistance than those of Pt/C.