Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, Liaoning, 110016 (China); School of Chemistry and Life Science, Anshan Normal University, Anshan, Liaoning, 114005 (China).
Angew Chem Int Ed Engl. 2014 Sep 26;53(40):10673-7. doi: 10.1002/anie.201405314. Epub 2014 Aug 12.
Non-precious Fe/N co-modified carbon electrocatalysts have attracted great attention due to their high activity and stability in oxygen reduction reaction (ORR). Compared to iron-free N-doped carbon electrocatalysts, Fe/N-modified electrocatalysts show four-electron selectivity with better activity in acid electrolytes. This is believed relevant to the unique Fe-N complexes, however, the Fe-N structure remains unknown. We used o,m,p-phenylenediamine as nitrogen precursors to tailor the Fe-N structures in heterogeneous electrocatalysts which contain FeS and Fe3 C phases. The electrocatalysts have been operated for 5000 cycles with a small 39 mV shift in half-wave potential. By combining advanced electron microscopy and Mössbauer spectroscopy, we have identified the electrocatalytically active Fe-N6 complexes (FeN6, [Fe(III)(porphyrin)(pyridine)2]). We expect the understanding of the FeN6 structure will pave the way towards new advanced Fe-N based electrocatalysts.
非贵金属 Fe/N 共修饰碳电催化剂因其在氧还原反应（ORR）中具有高活性和稳定性而受到广泛关注。与无铁氮掺杂碳电催化剂相比，Fe/N 修饰的电催化剂在酸性电解质中具有更好的活性和四电子选择性。这被认为与独特的 Fe-N 配合物有关，但 Fe-N 结构仍不清楚。我们使用邻、间、对苯二胺作为氮前体，在含有 FeS 和 Fe3C 相的多相电催化剂中调整 Fe-N 结构。电催化剂在 5000 个循环中运行，半波电位仅发生 39mV 的微小偏移。通过结合先进的电子显微镜和穆斯堡尔光谱学，我们已经确定了电催化活性的 Fe-N6 配合物（FeN6，[Fe(III)(卟啉)(吡啶)2]）。我们期望对 FeN6 结构的理解将为新型先进的 Fe-N 基电催化剂铺平道路。
