Nowadays, the hybrids of non-noble metal and heteroatom-doped carbon, especially, transition-metal-nitrogen-carbon materials, have been extensively studied as promising next-generation oxygen reduction reaction (ORR) catalysts in energy conversion. However, the pyrolysis of normal metal/nitrogen/carbon-containing precursors usually generates uncontrollable agglomeration or inhomogeneous microstructure, hence leading to insufficient exposure of the active sites and poor mass transport. In this work, a new strategy for fabricating N-doped-carbon-coated Fe₃O₄ (denoted as [email protected]₃O₄) is proposed by the pyrolysis of polyaniline (PANI)-coated Fe-based metal organic frameworks (MIL-101-Fe). The optimal catalyst exhibits a very positive ORR onset potential close to that of Pt/C, quasi-four-electron-transfer pathway and high long-term cycle stability in alkaline media. This work demonstrates the crucial role of thin PANI film (a highly conductive skeleton and heteroatoms sources) together with MOFs to rationalize the superior ORR performance for the resulting [email protected]₃O₄. The generality of the conductive-polymer-layer-assisted synthetic strategy is expected to further boost the electrocatalytic activity of universal non-noble-metal hybrid electrocatalyst for practical fuel-cell applications.

如今，已经广泛研究了非贵金属和杂原子掺杂碳的杂化物，特别是过渡金属-氮-碳材料，作为有前景的能量转化中的下一代氧还原反应（ORR）催化剂。但是，正常的含金属/氮/碳的前体的热解通常会产生无法控制的团聚或不均匀的微观结构，因此导致活性位点暴露不足和质量传输不良。在这项工作中，一种制造N掺杂碳涂层的Fe ₃ O ₄的新策略（表示为[email protected] ₃ O ₄）是由聚苯胺（PANI）涂层的铁基金属有机骨架（MIL-101-Fe）的热解提出的。最佳催化剂在碱性介质中具有接近Pt / C的非常正的ORR起始电位，准四电子转移途径和较高的长期循环稳定性。这项工作证明了薄的PANI薄膜（高导电性骨架和杂原子源）与MOF一起发挥关键作用，从而合理化了卓越的ORR性能，从而获得了[受电子邮件保护的] ₃ O ₄。导电聚合物层辅助合成策略的普遍性有望进一步提高通用非贵金属混合电催化剂在实际燃料电池应用中的电催化活性。