Non-precious iron–nitrogen-functionalized carbon (Fe–N–C) electrocatalysts for the oxygen reduction reaction (ORR) are prepared from ZIF-8 and iron acetylacetonate. The amount of Fe in the precursor mixture is varied to scrutinize the effect of Fe on the structural and catalytic properties of the resulting Fe–N–C. The electrocatalytic activity of the optimized sample in acidic electrolyte is comparable to that of commercial Tanaka Pt/C electrocatalyst. The catalysts were also assembled in a membrane electrode assembly as a cathode electrode for a single cell test, which shows remarkable fuel cell performance compared to other related studies of non-precious metal-based catalysts for the ORR. Such a high ORR catalytic performance can be ascribed to the synergistic effect of the Fe–N–C species, high-density pyridinic N species, N-doped carbon-encapsulated iron carbide (NC-Fe₃C) nanoparticles, and high electrical conductivity as well as the porous framework structure of the as-prepared ZIF-based Fe–N–C catalysts. In addition, different properties of catalysts prepared in a nitrogen or ammonia (NH₃) atmosphere are also investigated. Interestingly, it is found that NH₃ treatment helps not only to improve carbon porosity and nitrogen content but also to increase carbon graphitization and induce NC-Fe₃C formation, leading to enhanced ORR activity and durability of thus-prepared catalysts.

中文翻译：

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Fe-N-官能化碳电催化剂，由沸石咪唑酸盐骨架制得，用于还原氧：Fe和NH _3的处理效果†

用于氧化还原反应（ORR）的非贵重的铁-氮官能化碳（Fe-N-C）电催化剂是由ZIF-8和乙酰丙酮铁制备的。改变前体混合物中的Fe含量，以研究Fe对所得Fe–N–C的结构和催化性能的影响。优化后的样品在酸性电解质中的电催化活性与市售Tanaka Pt / C电催化剂相当。该催化剂还被组装在膜电极组件中，作为用于单电池测试的阴极电极，与其他有关ORR的非贵金属基催化剂的相关研究相比，该催化剂表现出了卓越的燃料电池性能。如此高的ORR催化性能可归因于Fe–N–C物种，高密度吡啶类N物种的协同效应，₃ C）纳米粒子，高电导率以及所制备的ZIF基Fe–N–C催化剂的多孔骨架结构。此外，还研究了在氮气或氨气（NH ₃）气氛中制备的催化剂的不同性能。有趣的是，发现NH ₃处理不仅有助于改善碳的孔隙率和氮含量，而且还有助于增加碳的石墨化作用并诱导NC-Fe ₃ C的形成，从而提高了由此制备的催化剂的ORR活性和耐久性。