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 AEMFC is a clean energy equipment. However, its 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 simply one-step thermal strategy to synthesize N-doped porous carbon encapsulated Fe and Ni bimetal (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 bimetallic action of FeNi, increased graphitic content, higher Fe/Ni-N4 content, larger BET surface area and the presence of mesopore structures. Moreover, FeNi-Ni-C-1-1-1000 exhibited higher half-wave potential than Ni-N-C-1000 and Fe-N-C-1000 due to the smaller particle size and lager BET surface area of FeNi-N-C after the doping of Ni into Fe-N-C. Finally, FeNi-N-C-1-1-1000 was utilized as the cathode in the AEMFC with a loading of 2.0 mg·cm-2, resulting in the  AEMFC achieving the best peak power density of 545 mW·cm-2, surpassing that of 20 wt % Pt/C (375 mW·cm-2) by 170 mW·cm-2.

Keywords: Non-precious metal catalysts, metal-organic framework, ORR activity, Durability, AEMFC