Effect of iron precursor on the activity and stability of PtFe/C catalyst for oxygen reduction reaction

The stability of iron species in PtFe/C catalyst in acidic medium is a grand challenge to maintain a high activity and stability for oxygen reduction reaction (ORR) via the geometric and electronic effect. Herein, we report that the use of ammonium ferric citrate with a high thermal stability, instead of iron nitrate, greatly improves the stability of iron species in PtFe/C catalyst in acidic medium after high-temperature reduction treatment. The resulting PtFe/C catalyst with ammonium ferric citrate as iron precursor shows much improved activity and stability for ORR than the counterpart using iron nitrate due to enhanced proportion of PtFe alloy in the PtFe/C catalyst.