Iron- and nitrogen-codoped carbon (Fe–N–C) catalysts with Fe–N₄ active sites offer a promising alternative to noble metal-based materials for the oxygen reduction reaction (ORR), which is essential for energy storage and conversion in applications such as fuel cells and metal–air batteries. This study presents a straightforward and scalable method to synthesize an efficient ORR electrocatalyst that consists of nitrogen-doped carbon and a high density of atomically dispersed single iron atoms, created through the pyrolysis of Fe-zeolitic imidazolate framework (Fe-ZIF-8) precursors. The Fe-ZIF-8 framework effectively restricts the migration and agglomeration of iron species, resulting in obtained Fe–N–C with conductive, mesoporous carbon structures and abundant Fe–N₄ sites. This structure provides excellent electrocatalytic activity for the ORR, demonstrated by a positive onset potential of 0.985 V vs RHE and a half-wave potential of 0.905 V vs the reversible hydrogen electrode (RHE) in alkaline media, outperforming commercial Pt/C. Additionally, when used as the cathode in a zinc–air battery, the Fe–N–C catalyst delivers high maximum power densities of 170.1 mW cm^–2, showcasing its potential for practical energy storage applications.

中文翻译：

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通过丰富的单铁原子提高氧还原反应性能，用于先进的锌-空气电池


具有 Fe-N₄ 活性位点的铁和氮共掺杂碳 （Fe-N-C） 催化剂为氧还原反应 （ORR） 提供了一种有前途的贵金属基材料替代品，这对于燃料电池和金属-空气电池等应用中的能量储存和转换至关重要。本研究提出了一种简单且可扩展的方法来合成一种高效的 ORR 电催化剂，该方法由氮掺杂碳和高密度原子分散的单铁原子组成，通过热解 Fe-沸石咪唑酸盐框架 （Fe-ZIF-8） 前驱体产生。Fe-ZIF-8 框架有效地限制了铁种类的迁移和团聚，从而获得具有导电介孔碳结构和丰富的 Fe-N₄ 位点的 Fe-N-C。这种结构为 ORR 提供了出色的电催化活性，在碱性介质中，与 RHE 相比具有 0.985 V 的正起始电位，与可逆氢电极 （RHE） 相比，其半波电位为 0.905 V，优于商用 Pt/C。此外，当用作锌-空气电池中的阴极时，Fe-N-C 催化剂可提供 170.1 mW cm^–2 的高功率密度， 展示了其在实际储能应用中的潜力。