Pyrolyzed iron–cobalt/polypyrrole/reduced graphene oxide as an effective cathode electrocatalyst for oxygen reduction reaction in an alkaline medium

The slow kinetics of the oxygen reduction reaction (ORR) catalyzed by cathode electrocatalysts in fuel cells and metal-air batteries is a major problem. In this study, a composite material consisting of Fe and Co on polypyrrole (PPy)/graphene oxide (GO) support was prepared. The resulting iron-cobalt/polypyrrole/graphene oxide (FeCo/PPy/GO) composite was then pyrolyzed at 900 °C using a tube furnace under N₂ atmosphere at a ramp rate of 5 °C min⁻¹ for 1 h. The resulting pyrolyzed electrocatalyst, 900FeCo/PPy/rGO, was characterized using various materials characterization techniques. The effect of pyrolysis temperature (i.e., 800, 900, 1000 °C) of FeCo/PPy/rGO on the ORR activity was investigated using CV and LSV. The 900FeCo/PPy/rGO catalyst composite exhibited the best ORR activity with an onset potential of −0.08 V and a half-wave potential at approximately −0.18 V with an electron transfer number of 3.79, compared to 800FeCo/PPy/rGO and 1000FeCo/PPy/rGO composites. Moreover, the 900FeCo/PPy/rGO catalyst composite showed significantly better electrochemical stability than the benchmark 20 % Pt/C. These results suggest that 900FeCo/PPy/rGO could be a cost-effective substitute for Pt-based ORR electrocatalysts.