Catalytic activity of monometric metal macrocycles for oxygen reduction reaction (ORR) was investigated using rotating disk electrode voltammetry in acidic media. Iron(II) phthalocyanines (FePc) and cobalt(II) tetraphenylporphyrins (CoTPP) were immobilized on Au surfaces through molecular wires with different terminal groups of pyridine and isocyanide. The measured ORR behavior of FePc was largely influenced by the axial ligand while CoTPP promoted only the two-electron reaction regardless of the axial ligand. The FePc immobilized with pyridine was easily detached from the surface under the ORR condition, and was able to promote the four-electron reaction only under the high overpotential application. The FePc with isocyanide was more stable with the activity for the four-electron reaction, due to stronger electron donation to Fe central ions.

中文翻译：

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旋转盘电极对酞菁铁（II）修饰电极在酸性介质中还原氧的催化活性的研究

使用旋转盘电极伏安法在酸性介质中研究了单金属大环化合物对氧还原反应（ORR）的催化活性。铁（II）酞菁（FePc）和钴（II）四苯基卟啉（CoTPP）通过具有吡啶和异氰酸酯不同末端基团的分子线固定在Au表面上。FePc的ORR行为受轴向配体的影响很大，而CoTPP则仅促进双电子反应，而与轴向配体无关。在ORR条件下，固定有吡啶的FePc很容易从表面上脱离，并且仅在高电势下才能够促进四电子反应。带有异氰化物的FePc具有更稳定的四电子反应活性，这是因为电子对Fe中心离子的供电能力更强。