Polyvinyl-imidazole and vinyl-ferrocene composite-derived Fe-N-C electrocatalysts for oxygen reduction reaction in anion exchange membrane fuel cells

Anion exchange membrane fuel cells (AEMFCs) are sustainable and clean electrochemical energy conversion devices due to their high feasibility of employing platinum-free catalysts for oxygen reduction reaction (ORR). Herein, we selected vinylferrocene and vinylimidazole polymer composite with their conductive and coordination networks anticipated for their diverse electrochemical applications. The prepared catalyst materials possess highly abundant ORR-active centers and favourable physico-chemical properties like high specific surface area, pore size distribution, defects and surface chemical states, which are confirmed by X-ray diffraction, Raman spectroscopy, N₂ physisorption, X-ray photoelectron spectroscopy and scanning transmission electron microscopy. The catalyst materials are assessed through optimization of different ratios of vinylferrocene and vinylimidazole along with zinc nitrate treatment to attain the prominent textural properties for efficient electrocatalytic ORR activity in 0.1 M KOH electrolyte and the half-wave potential is 0.80–0.85 V vs. RHE, which is comparable to that of the Pt/C benchmark. Amongst, FerNC-T2 shows higher ORR activity than other prepared catalysts. This is accredited to the highly active Fe-N_x sites and hierarchical porous structure of the electrocatalyst. This work made a significant impact in developing efficient electrocatalysts for AEMFC cathodes owing to the excellent electrochemical stability in RDE study and high-power density in an AEMFC (344 mW cm⁻²).