Abstract

This work confirms formation of surface films of 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (H₂T(4-NH₂Ph)P) in dimethylsulfoxide in the potential range of oxygen electroreduction. Kinetics of variation of faradaic currents and of the interface characteristics are studied at the working electrode potentials of +0.5 V (porphyrin electrooxidation), –0.9 V (oxygen electroreduction), and –1.25 V (coreduction of porphyrin and oxygen). It is shown that the working electrode surface is passivated at the potential of +0.5 V and faradaic currents decrease fast. At the potentials of –0.9 and –1.25 V, the working electrode surface passivation is less pronounced. As shown by analysis of electrode impedance spectra, a film is formed on the electrode surface under electroreduction conditions (–0.9 and –1.25 V), as opposed to electrooxidation conditions (+0.5 V). Charge transport through this film can be characterized by modeling the interface impedance. The kinetics of variation of the interface parameters allow estimating the stage mechanism of film formation and restructuring of the formed layer.

中文翻译：

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基于四（4-氨基苯基）卟啉的薄膜诱导沉积动力学

摘要

这项工作证实了5,10,15,20-四（4-氨基苯基）卟啉（H ₂ T（4-NH ₂Ph）P）在二甲基亚砜中进行电还原的电位范围。在+0.5 V（卟啉电氧化），– 0.9 V（氧气电还原）和–1.25 V（卟啉和氧气的共轭）的工作电极电势下，研究了法拉第电流和界面特性的变化动力学。结果表明，工作电极表面在+0.5 V的电势下被钝化，法拉第电流快速下降。在–0.9和–1.25 V的电势下，工作电极表面的钝化作用不太明显。如对电极阻抗谱的分析所示，与电氧化条件（+0.5 V）相反，在电还原条件（–0.9和–1.25 V）下在电极表面形成了一层膜。可以通过对界面阻抗建模来表征通过该薄膜的电荷传输。