The pyrolysis procedure plays a key role in fabricating Fe–N-doped carbon (Fe/N/C) electrocatalysts for the oxygen reduction reaction. In this paper, a new method is presented for preparation of an efficient Fe/N/C oxygen reduction catalyst by employing NH₄Cl–NaCl mixed salts to assist the pyrolysis of a poly-m-phenylenediamine (P-mPDA) precursor. In this approach, the NH₄Cl salt functions as a secondary precursor to increase the nitrogen doping and surface area of the catalyst. The NaCl works as template to construct a continuous 3-dimensional (3D) framework and as a salt sealed reactor for high-temperature pyrolysis. As a result of increased nitrogen doping, and pore engineering, an optimized Fe/N/C ORR catalyst with high surface area, hierarchical pore structure and a high density active sites is obtained. Consequently, the catalytic activities of the resultant Fe/N/C catalyst, represented by the half-wave potentials (E_1/2), are boosted from 0.760 to 0.929 V in 0.1 M KOH basic solution and from 0.66 to 0.79 V in 0.1 M HClO₄ acidic solution, when compared to the Fe/N/C catalyst directly pyrolyzed from the same precursor. The outstanding performance of the catalyst under practical conditions was also assessed with a homemade Zn–air battery.

中文翻译：

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NH4Cl–NaCl混合盐辅助热解路线，用于制备高性能Fe / N / C氧还原反应催化剂

热解过程在制备用于氧还原反应的Fe-N掺杂碳（Fe / N / C）电催化剂中起着关键作用。在本文中，一种新的方法是通过采用NH提出了制备一种有效的Fe / N / C的氧还原催化剂的₄ CL-NaCl的混合盐，以协助一个聚热解米苯二胺（P-MPDA）前体。在这种方法中，NH ₄Cl盐用作辅助前体以增加催化剂的氮掺杂和表面积。NaCl作为模板来构建连续的3维（3D）框架，并作为盐密封的反应器进行高温热解。由于增加的氮掺杂和孔工程，获得具有高表面积，分级孔结构和高密度活性位点的优化的Fe / N / C ORR催化剂。因此，由半波电势（E _1/2）表示的所得Fe / N / C催化剂的催化活性在0.1 M KOH碱性溶液中从0.760升高到0.929 V，在0.1 M KOH中从0.66升高到0.79 V盐酸₄酸性溶液，与从同一前体直接热解的Fe / N / C催化剂相比。自制的锌空气电池还评估了催化剂在实际条件下的出色性能。