N-doped porous carbon encapsulated Fe and Ni bimetal derived from MOFs as efficient oxygen reduction reaction catalysts for anion exchange membrane fuel cell

Abstract

The anion exchange membrane fuel cell (AEMFC) represents a promising avenue in clean energy equipment. However, its practical application is limited due to the high cost of Pt-based catalysts. Therefore, it is necessary to develop cheap and efficient non-precious metal catalysts. Here in, we employed a simple one-step thermal strategy to synthesize N-doped porous carbon encapsulated Fe and Ni bimetal catalysts (FeNi-N-C-1-1-Ts, T = 900, 950, 1000, 1050 and 1100 ℃). Among these catalysts, FeNi-N-C-1-1-1000 exhibited the highest half-wave potential of 0.885 V, 5 mV higher than 20 wt% Pt/C (0.880 V). Furthermore, it demonstrated a dominant 4e^- reduction pathway, exceptional durability and high resistance to methanol. These excellent performances were attributed to the synergistic effect of FeNi bimetallicaction, increased graphitic content, higher Fe/Ni-N₄ content, larger BET surface area and the presence of mesoporous structures. Moreover, FeNi-N-C-1-1-1000 exhibited higher half-wave potential than Ni-N-C-1000 and Fe-N-C-1000 owing to the smaller particle size and larger BET surface area of FeNi-N-C after the doping of Ni into Fe-N-C. Finally, FeNi-N-C-1-1-1000 was employed as the cathode in the AEMFC with a loading of 2.0 mg·cm⁻², resulting in the highest peak power density of 545 mW·cm⁻², surpassing that of 20 wt% Pt/C (375 mW·cm⁻²) by 170 mW·cm⁻².