Semi‐Closed Pyrolysis Synthesis of Iron Oxide–Graphitic Carbon Nitride on Reduced Graphene Oxide for Oxygen Reduction Reaction

ABSTRACT The high cost and limited durability of platinum‐based electrocatalysts constrain the widespread utilization of fuel cells as renewable energy systems. We demonstrate here an ambient atmosphere, semi‐closed pyrolysis strategy for the preparation of an iron oxide–graphitic carbon nitride hybrid anchored on reduced graphene oxide (Fe x O y ‐g‐C 3 N 4 @rGO). Unlike conventional synthesis routes that require inert‐gas infrastructure, our approach streamlines the process and lowers operational costs without compromising electrocatalytic performance. The composite, prepared by heating graphene oxide, urea, and FeCl 3 ·6H 2 O at 400°C, demonstrates enhanced oxygen reduction reaction (ORR) activity compared to g‐C 3 N 4 @rGO, achieving onset and half‐wave potentials of –0.145 and –0.318 V (vs. Ag/AgCl), respectively, with an apparent electron transfer number of n = 3.43, indicating a mixed pathway with a strong 4 e − contribution. Although its activity is slightly lower than that of commercial Pt/C (loading: 386 vs. 849 µg cm −2 for Fe x O y ‐g‐C 3 N 4 @rGO), the catalyst exhibits superior operational stability. This work not only validates the efficacy of semi‐closed pyrolysis for scalable and sustainable electrocatalyst production but also advances the design of nonprecious metal‐based catalysts for energy conversion, furthering the findings of our earlier investigations.