The introduction of pyridinic nitrogen (pyri‐N) into carbon‐based electrocatalysts for the oxygen reduction reaction is considered to create new active sites. Herein, the role of pyri‐N in such catalysts was investigated from a mechanistic viewpoint using carbon black (CB)‐supported pyri‐N‐containing molecules as model catalysts; the highest activity was observed for 1,10‐phenanthroline/CB. X‐ray photoemission spectroscopy showed that in acidic electrolytes, both pyri‐N atoms of 1,10‐phenanthroline could be protonated to form pyridinium ions (pyri‐NH⁺). In O₂‐saturated electrolytes, one of the pyri‐NH⁺ species was reduced to pyri‐NH upon the application of a potential; no such reduction was observed in N₂‐saturated electrolytes. This behavior was ascribed to electrochemical reduction of pyri‐NH⁺ occurring simultaneously with the thermal adsorption of O₂, as supported by DFT calculations. According to these calculations, the coupled reduction was promoted by hydrophobic environments.

中文翻译：

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吡啶氮在碳电催化剂上氧还原反应机理中的作用

认为将吡啶二氮（pyri-N）引入碳基电催化剂中以进行氧还原反应可创建新的活性位点。在这里，从机理的角度，使用炭黑（CB）负载的含pyri-N的分子作为模型催化剂，研究了pyri-N在这类催化剂中的作用；1,10-菲咯啉/ CB的活性最高。X射线光电子能谱显示，在酸性电解质中，1,10-菲咯啉的两个pyrn-N原子都可以被质子化而形成吡啶鎓离子（pyri-NH ⁺）。在O ₂饱和电解质中，通过施加电势，一种pyri-NH ⁺物种被还原为pyri-NH。在N _2中未观察到这种减少饱和电解质。这种行为归因于DFT计算支持的同时发生的O ₂热吸附同时发生的pyri-NH ^+的电化学还原。根据这些计算，疏水环境促进了偶合还原。