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首页> 外文期刊>Journal of Electroanalytical Chemistry: An International Journal Devoted to All Aspects of Electrode Kinetics, Interfacial Structure, Properties of Electrolytes, Colloid and Biological Electrochemistry >Oxygen reduction reaction in acid medium at iron phthalocyanine dispersed on high surface area carbon substrate: tolerance to methanol, stability and kinetics
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Oxygen reduction reaction in acid medium at iron phthalocyanine dispersed on high surface area carbon substrate: tolerance to methanol, stability and kinetics

机译：酸性介质中的酞菁铁在高表面积碳基质上分散时的氧还原反应：对甲醇的耐受性，稳定性和动力学

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The electrocatalytic performance of iron phthalocyanine, FePc, dispersed on a high surface area carbon substrate (Vulcan XC 72) was investigated in acid medium. The polarisation curve of oxygen reduction on the FePc/C catalyst in a methanol containing O-2-saturated electrolyte was compared to that obtained on a platinum catalyst. Results showed clearly that FePc/C catalyst is totally insensitive to the presence of methanol and becomes a better catalyst than the Pt/C catalyst for the oxidation reduction reaction (orr) at low overpotentials, indicating that FePc/C catalyst is a good alternative to platinum based catalysts as a cathode catalyst for low working temperatures fuel cells. The major problem of this catalyst in acid medium is its poor long-term stability, which was demonstrated by electrochemical measurements and characterized by in situ infrared reflectance spectroscopy experiments. The infrared spectra showed that FePc degradation occurred via the substitution of the central metal of the macrocycle by two protons, leading to the formation of a free base phthalocyanine which is known to be inactive for oxygen reduction catalysis. From this observation, it was possible to improve the FePc stability by using a gas diffusion electrode. Under these conditions, oxygen reduction was performed on a FePc/C electrode for at least 24 h with a constant current density of -25 mA cm(-2) at room temperature. Finally, cyclic voltammetry experiments at different electrode rotation rates 0 led to determine the Kouteck-Levich plots from which it was shown that the kinetic parameters for the orr at FePc/C electrodes are similar to those obtained at platinum particles. The total number of exchanged electrons n(t) during the orr on the FePc/C catalyst was determined by rotating ring disc electrode experiments leading to nt close to 3.9-4. (c) 2004 Elsevier B.V. All rights reserved.
机译：研究了在酸性介质中分散在高表面积碳基底（Vulcan XC 72）上的酞菁铁（FePc）的电催化性能。比较了在含O-2-饱和电解质的甲醇中FePc / C催化剂上氧还原的极化曲线与在铂催化剂上获得的极化还原曲线。结果清楚地表明，FePc / C催化剂对甲醇的存在完全不敏感，并且在低超电势下成为比氧化还原反应（orr）的Pt / C催化剂更好的催化剂，表明FePc / C催化剂是甲醇的良好替代品。铂基催化剂用作低工作温度燃料电池的阴极催化剂。该催化剂在酸性介质中的主要问题是其长期稳定性差，这通过电化学测量证明并通过原位红外反射光谱实验表征。红外光谱表明，FePc的降解是通过大环的中心金属被两个质子取代而发生的，从而导致形成了游离碱酞菁，该酞菁对氧还原催化是无活性的。根据该观察结果，可以通过使用气体扩散电极来提高FePc的稳定性。在这些条件下，在室温下以-25 mA cm（-2）的恒定电流密度在FePc / C电极上进行至少24 h的氧气还原。最后，在不同电极旋转速率0下的循环伏安法实验确定了Kouteck-Levich图，从该图可以看出，在OrPc / C电极上orr的动力学参数与在铂颗粒上获得的动力学参数相似。通过旋转环盘电极实验确定nt接近3.9-4来确定FePc / C催化剂在orr期间的交换电子总数n（t）。 （c）2004 Elsevier B.V.保留所有权利。

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