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Developing a low-price, high catalytic activity, and strong durability electrocatalyst for alkaline oxygen reduction reaction (ORR) is significantly important for anion exchange membrane fuel cell (AEMFC). Herein, Co and Mn salts were added into ZIF-8 to obtain CoMn-ZIF-Ac-2. Co and Mn embedded in nitrogen-doped microporous carbon (CoMn-N-C-Ac-2-Ts, T = 700 , 800, 900, and 1000°C) were obtained by carbonizing CoMn-ZIF-Ac-2 at various temperature. The influence of various pyrolysis temperature and molar ratios between Co and Mn toward ORR catalytic activity was researched. For CoMn-N-C-Ac-2-Ts, CoMn-N-C-Ac-2-800 had the highest ORR catalytic activity with the half-wave potential of 0.875 V in 0.1 M KOH, only 5 mV lower than that of 20 wt % Pt/C. Besides, high 4e- selectivity, excellent stability (retaining 100% for 20 h at 0.6 V vs. RHE), and methanol tolerance are also exhibited. In addition, CoMn-N-C-Ac-2-800 exhibited better ORR activity than Mn-N-C-Ac-800 and Co-N-C-Ac-800, which was attributed to more Co-N4, more MnIII species, and higher surface area. Moreover, the AEMFC based on the CoMn-N-C-Ac-2-800 cathode catalyst obtained a maximal power density of 291 mW·cm-2, which was 78% of the P max achieved with 20 wt % Pt/C (375 mW·cm-2). The highest ORR performance for CoMn-N-C-Ac-2-800 was contributed by the highest defect degree, the most amounts of Co/Mn-N4 active site, the maximum BET surface area, and micropore structure. [ABSTRACT FROM AUTHOR]

The development of high-performance nonprecious metal catalysts for oxygen reduction reactions is critical for the commercialization of fuel cells. In this paper, we report a non-precious catalyst with high-performance, in which Fe and Fe3C is embedded in nitrogen-doped carbon nanofibers (MIL-N-CNFs) by co-electrospinning Fe-MIL and polyacrylonitrile (PAN) and pyrolyzing. The mass ratio of Fe-MIL to PAN in the precursors and the pyrolysis temperature were optimized to be 1.5 and treated at 800 °C, respectively. The optimized catalyst exhibited an onset potential of 0.950 V and a half-wave potential of 0.830 V in alkaline electrolytes, thanks to the improved mass transfer kinetics in a meso-porous structure and enhanced reaction kinetics by confined Fe and Fe3C particles. Additionally, the optimized catalyst showed a better methanol tolerance than the commercial 20 wt.% Pt/C, indicating a potential application in direct methanol fuel cells. Serving as the cathode in CCM, the anion-exchange membrane fuel cell reaches a power density of 192 mW cm−2 at 428 mA cm−2 and 80 °C. [ABSTRACT FROM AUTHOR]

• A simple one-step thermal way was employed to synthesize FeNi-N-C-1-1-1000. • After the doping of Ni into Fe-N-C, the particle size of FeNi-N-C became smaller and BET surface area became larger. • 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). • FeNi-N-C-1-1-1000 achieved the best peak power density of 545 mW·cm−2 in AEMFC, surpassing 20 wt% Pt/C (375 mW·cm−2) by 170 mW·cm−2. 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-N 4 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. [ABSTRACT FROM AUTHOR]