Formic acid electrooxidation on Pd in acidic solutions studied by surface-enhanced infrared absorption spectroscopy
Formic acid electrooxidation on Pd in acidic solutions studied by surface-enhanced infrared absorption spectroscopy
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DOI：
10.1039/b805955a
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发表时间：
2008-01-01
影响因子：
3.3
通讯作者：
Osawa, Masatoshi
中科院分区：
文献类型：
--
作者：
Miyake, Hiroto;Okada, Tatsuhiro;Osawa, Masatoshi
本文报道了在硫酸和高氯酸中甲酸在钯电极上电催化氧化的机理研究。衰减全反射模式（ATR-SEIRAS）中的表面增强红外吸收光谱显示CO，桥键合的甲酸盐，碳酸氢盐和支持阴离子在电极表面上的吸附。中毒的Pd表面的CO，形成的甲酸脱水，是非常缓慢的，几乎不影响甲酸的氧化。吸附的阴离子更强烈的顺序（氢）硫酸4碳酸氢根4高氯酸盐，其中最强烈的吸附（氢）硫酸盐显着抑制在双层区域的甲酸氧化。氧化也被抑制在较高的电位在这两种酸的Pd表面的氧化。只有当甲酸氧化被抑制时，才能检测到吸附的甲酸盐。结果表明，甲酸是一个短暂的反应中间体，在甲酸氧化，因此检测时，其分解产生CO2被抑制。Pd的高电催化活性可以归因于对CO污染的高耐受性以及对甲酸盐分解的高催化活性。
A mechanistic study of electrocatalytic oxidation of formic acid on Pd in sulfuric and perchloric acids is reported. Surface-enhanced infrared absorption spectroscopy in the attenuated total reflection mode (ATR-SEIRAS) shows the adsorption of CO, bridge-bonded formate, bicarbonate, and supporting anions on the electrode surface. Poisoning of the Pd surface by CO, formed by dehydration of formic acid, is very slow and scarcely affects formic acid oxidation. The anions are adsorbed more strongly in the order of (bi) sulfate 4 bicarbonate 4 perchlorate, among which the most strongly adsorbed (bi) sulfate considerably suppresses formic acid oxidation in the double layer region. The oxidation is suppressed also at higher potentials in both acids by the oxidation of the Pd surface. Adsorbed formate is detected only when formic acid oxidation is suppressed. The results show that formate is a short-lived reactive intermediate in formic acid oxidation and is hence detected when its decomposition yielding CO2 is suppressed. The high electrocatalytic activity of Pd can be ascribed to the high tolerance to CO contamination and also high catalytic activity toward formate decomposition.