Transition metal/nitrogen/carbon (M-N/C) catalysts are considered as one of the most promising candidates to replace Pt/C catalysts for oxygen reduction reactions (ORRs). Here, we have designed novel reduced graphene oxide (rGO)-supported Fe–N-doped carbon (Fe–N–C/rGO) catalysts via simple pyrolysis of polypyrrole (Ppy)–FeO–GO composites. The as-prepared catalysts induced an onset potential of 0.94 V and a half-wave potential of 0.81 V in alkaline solutions, which is much better than those of the counterpart N–C and N–C/rGO catalysts and comparable to that of Pt/C catalysts. Moreover, the Fe–N–C/rGO catalysts showed improved durability and higher tolerance against methanol crossover than Pt/C in alkaline solutions. This superior ORR performance can be ascribed to the combined catalytic effect of both Fe-based nanoparticles (Fe₃O₄, Fe₄C) and Fe–N_x sites, as well as fast mass transfer and accessible active sites benefiting from the mesoporous structure and high specific surface area. This work provides new insight for synthesis of a more promising nonplatinum electrocatalyst for metal–air batteries and fuel-cell applications.

中文翻译：

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Fe-N掺杂的介孔碳，在还原的氧化石墨烯氧化物上负载有双重活性位，可用于高效氧还原催化剂

过渡金属/氮/碳（MN / C）催化剂被认为是代替Pt / C催化剂进行氧还原反应（ORR）的最有希望的候选者之一。在这里，我们通过简单地热解聚吡咯（Ppy）-FeO-GO复合材料，设计了新颖的还原型氧化石墨烯（rGO）负载的Fe-N掺杂碳（Fe-N-C / rGO）催化剂。所制备的催化剂在碱性溶液中产生的起始电势为0.94 V，半波电势为0.81 V，这比相应的N-C和N-C / rGO催化剂要好得多，与Pt相当/ C催化剂。此外，与碱性溶液中的Pt / C相比，Fe–N–C / rGO催化剂显示出更高的耐久性和更高的耐甲醇穿透性。这种卓越的ORR性能可归因于两种铁基纳米颗粒（Fe₃ O ₄，Fe ₄ C）和Fe–N _x位点，以及快速的质量转移和可访问的活性位点，得益于中孔结构和高比表面积。这项工作为合成用于金属-空气电池和燃料电池应用的更有希望的非铂电催化剂提供了新的见识。