Electrochemical Oxidation of O-Containing Substances and Energy Conversion

1.甲醇电氧化反应机理在精密控制条件下，研究了甲醇在铂电极上的反应动力学。强吸附物种在恒定表面覆盖度下的Tafel关系表明，存在两个势区，它们的主要反应路径不同。强吸附物种与OH(A)的表面反应在E&gt；约为0.55V时为速率控制步骤，而甲醇的氧化吸附形成反应中间体在E&lt；约为0.55V时成为速率控制步骤。在后一电势区，强吸附物种不被氧化，因此其在表面的积累降低了氧化吸附的速率，从而降低了总的氧化速率。单晶电极的制备及其电化学行为研究了氢、氧在酸、碱…溶液中在铂低、高指数晶面上的吸附行为更多i解决方案。这些特征随表面结构和溶液的pH值而系统地变化，并根据各自表面的阶梯和阶梯进行了讨论。对于吸附的氢，铂(111)晶面主要提供长程有序吸附中心，而铂(100)晶面主要提供短程有序吸附中心。这些被吸附的氢不参与析氢反应。反应中间体是顶部的氢原子。还考察了吸附CO的电化学行为。甲醇在铂固相萃取电极上的氧化用钼修饰铂固相萃取电极可使甲醇的氧化电位降低约0.15V(反应速率提高约10^2倍)。Mo(III)/Mo(IV)的氧化还原对对提高铂电极的催化活性起着关键作用。对钼和甲醇共吸附电极的伏安曲线的扩展分析表明，当钼和甲醇物种的覆盖率相等时，氧化电流最大。并对其双作用机理进行了探讨。较少

1. Reaction Mechanism of Methanol Electrooxidation The reaction kinetics for the oxidation of methanol on a platinum electrode have been examined under precisely controlled conditions. The Tafel relations at constant surface coverages of the strongly adsorbed species show the existence of two potential regions where the predominant reaction path is different. The surface reaction of the strongly adsorbed species with OH (a) is rate determining at E>ca. 0.55 V, while the oxidative adsorption of methanol to form a reactive intermediate becomes the rate-determining step at E<ca. 0.55 V. In the latter potential region, the strongly adsorbed species is not oxidized so that its accumulation on the surface decreases the rate of the oxidative adsorption and thereby the total oxidation rate.2. Preparation ofSingle Crystal Electrode and its Electrochemical Behavior The electrochemical behavior of hydrogen and oxygen adsorption on platinum low- and high-index planes was examined in acid and alkal … More i solutions. The features varied systematically with the surface structure and the pH of solution and are discussed in terms of steps and terraces of the respective surfaces. With respect to adsorbed hydrogen, Pt (111) provides mainly a long-range ordered adsorption site, Pt (100) mainly short-range ordered site, respectively. These adsorbed hydrogens do not take part in the hydrogen evolution reaction. The reaction intermediate is the on-top hydrogen atom. Electrochemical behavior of adsorbed CO is also examined.3. Methanol Oxidation at Pt-SPE Electrode Modification of Pt-SPE electrode with molybdenum reduces the oxidation potential of methanol by ca. 0.15 V (ca. 10^2 times higher reaction rate). The redox couple of Mo (III) / Mo (IV) plays a key role in the enhancement of the catalytic activity of the Pt electrode. An extended analysis of voltammograms of the electrode coadsorbed with molybdenum and methanol species showed that the highest oxidation current is obtained at an equal coverage of the molybdenum and methanol species. The bifunctional mechanism was discussed. Less