Recently, iron, nitrogen and sulfur codoped carbon-based materials have gained increasing attention for their synergistic effect towards superior electrocatalytic oxygen reduction performance. To gain insight into the contributions of the heteroatoms, we developed a facile and reproducible method for constructing Fe, N, S-codoped carbon frameworks derived from self-assembled Fe3O4 nanocrystal superlattices. The material constructed by the suggested method exhibited excellent ORR activity with more positive half-wave potential (∼ 0.869 V, vs RHE), higher diffusion-limiting current density (∼ 5.88 mA/cm2) and smaller Tafel slope (45 mV/dec) compared with Fe, N-codoped carbon frameworks and Pt/C. Notably, Fe3O4 nanocrystals served as both the building blocks for constructing carbon frameworks and the source of Fe residues leaving in the frameworks at the same time. By artificially tailoring the doping type and level as well as the homogeneousness of heteroatoms, the results discussed herein prove the importance of each kind of heteroatom in boosting ORR activity.

中文翻译：

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Fe，N，S掺杂的碳骨架源自纳米晶超晶格，具有增强的氧还原活性。

近来，铁，氮和硫共掺杂的碳基材料因其对优异的电催化氧还原性能的协同作用而受到越来越多的关注。为了深入了解杂原子的贡献，我们开发了一种简便且可重现的方法，用于构建自组装Fe3O4纳米晶体超晶格衍生的Fe，N，S掺杂的碳骨架。通过建议的方法构造的材料表现出出色的ORR活性，具有更高的正半波电位（〜0.869 V，相对于RHE），更高的扩散限制电流密度（〜5.88 mA / cm2）和更小的Tafel斜率（45 mV / dec）与铁，N掺杂碳骨架和Pt / C相比。值得注意的是 Fe3O4纳米晶体既是构建碳骨架的基础，又是同时残留在骨架中的Fe残留源。通过人为地调整杂原子的掺杂类型和水平以及均一性，本文讨论的结果证明了每种杂原子在提高ORR活性方面的重要性。