New mechanistic aspects of methanol oxidation
New mechanistic aspects of methanol oxidation
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DOI：
10.1016/j.jelechem.2004.05.016
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发表时间：
2004-10-01
影响因子：
4.5
通讯作者：
Iwasita, T
中科院分区：
文献类型：
--
作者：
Batista, EA;Malpass, GRP;Iwasita, T
在光滑的铂电极上，甲醇电氧化过程中的平行反应导致大量的甲醛、甲酸和二氧化碳的生成。本文用光滑多晶电极和铂(111)面电极测量了0.6V下不同产物的产额。对电解约15分钟后的溶液样品进行高效液相色谱分析。观察到了基础电解液对甲醇氧化速率的众所周知的影响：在0.5M的H_2SO_4溶液中获得的电流比在0.1M的HClO_4溶液中小。通过比较产物在两种电解液中的分布，合理地解释了这种影响的原因。这表明，硫酸盐的强吸附通过抑制形成吸附的CO中间体的解离步骤来阻碍甲醇的氧化。H_2SO_4的存在不影响生成其他可溶产物HCHO和HCOOH的反应。结果表明，后一种反应过程遵循Eley-RIdeas机理，而生成CO2的反应遵循Langmuir-HinShelwood机理。(C)2004爱思唯尔B.V.保留所有权利。
Parallel reactions during methanol electro-oxidation at smooth Pt electrodes lead to the formation of considerable amounts of HCHO and HCOOH together with CO2. In the present paper, the yields of different products at 0.6 V have been measured, using smooth polycrystalline and Pt(111) electrodes. Analysis of solution samples after ca. 15 min of electrolysis was performed via HPLC. The well-known effect of the base electrolyte on the rate of methanol oxidation is observed: lower currents are obtained in 0.5 M H2SO4 than in 0.1 M HClO4 solutions. The reason for this effect is rationalized by comparing the distribution of products in both electrolytes. This indicates that strong adsorption of sulfate hinders methanol oxidation by inhibiting the dissociative steps where the adsorbed CO intermediate is formed. The reactions forming the other soluble products, HCHO and HCOOH are not affected by the presence of H2SO4. It is suggested that the latter processes occur by an Eley-Rideal mechanism, while the reaction forming CO2 follows a Langmuir-Hinshelwood mechanism. (C) 2004 Elsevier B.V. All rights reserved.