Introducing catalytically-active Fe and N into carbon materials results in promising FeNC catalysts for oxygen reduction reaction. However, the doped Fe and N species are frequently subject to heavy loss in a traditional carbonization process owing to Fe agglomeration and evaporation of N-contained small molecules. Besides, pyrolysis may make materials sintering which embeds a large number of active sites in the bulk phase and impedes direct exposure of reactive centers to the reactants. We here report that when calcinations, the addition of ZnCl2, an ordinary salt with very wide melting temperature range well covering the carbonization process of the precursor iron porphyrin, can significantly enhance the doping level of the active species and simultaneously create highly porous structures for FeNC catalysts. The obtained FeNC demonstrates ultrahigh catalytic activities even significantly better than Pt/C in oxygen reduction reaction.

中文翻译：

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ZnCl2 盐促进 FeNC 的制备：提高活性物质的含量及其暴露以实现高效氧还原反应

将具有催化活性的 Fe 和 N 引入碳材料中，可以为氧还原反应提供有前景的 FeNC 催化剂。然而，在传统的碳化过程中，由于 Fe 的团聚和含 N 小分子的蒸发，掺杂的 Fe 和 N 物种经常遭受严重损失。此外，热解可能使材料烧结，从而在体相中嵌入大量活性位点并阻止反应中心直接暴露于反应物。我们在这里报告说，当煅烧时，添加 ZnCl2，一种具有非常宽的熔化温度范围的普通盐，很好地覆盖了前体铁卟啉的碳化过程，可以显着提高活性物质的掺杂水平，同时为 FeNC 创造高度多孔的结构催化剂。