Electrochemical Oxidation of O-Containing Substances and Energy Conversion

含O物质的电化学氧化和能量转换

• 批准号: 01470075
• 负责人: KITA Hideaki
• 金额: $ 3.84万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01470075/
• 关键词: Reaction mechanism of electrooxidation of methanol; Analysis of time-dependent kinetics; Methanol fuel cell; Adsorbed hydrogen on Pt single crystal planes; Hydrogen electrode reaction and adsoarbed hydrogen; Solid polymer electrolyte membrane electro

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

1. 在精确控制的条件下，研究了甲醇在铂电极上氧化的反应动力学。在强吸附物质的恒定表面覆盖率下，Tafel关系表明存在两个主要反应路径不同的潜在区域。强吸附物质与OH (a)的表面反应速率决定于e> ca。0.55 V时，甲醇氧化吸附生成反应中间体成为决定反应速率的步骤。0.55 V。在后一电位区，强吸附物质不被氧化，因此其在表面的积聚降低了氧化吸附速率，从而降低了总氧化速率。单晶电极的制备及其电化学性能研究了在酸、碱溶液中铂在低折射率和高折射率平面上吸附氢、氧的电化学行为。这些特征随着表面结构和溶液pH值的不同而有系统地变化，并从各自表面的台阶和梯田的角度进行了讨论。对于吸附的氢，Pt（111）主要提供远程有序吸附位点，Pt（100）主要提供短程有序吸附位点。这些吸附的氢不参与析氢反应。反应中间体是上面的氢原子。对吸附CO的电化学行为也进行了研究。用钼修饰Pt-SPE电极可使甲醇的氧化电位降低约0.15 V（反应速率提高约10^2倍）。Mo (III) / Mo （IV）氧化还原对提高Pt电极的催化活性起关键作用。对钼和甲醇共吸附电极的伏安图进行了扩展分析，结果表明，当钼和甲醇共吸附电极的覆盖率相等时，氧化电流最高。讨论了双功能机理。少

项目成果

J.Wang: "Metal electrodes bonded on solid polymer electrolyte membrane(SPE)ーVI.Methanol oxidation on molybdenum modified PtーSPE electrode" Electrochimica Acta. 35. 323-328 (1990)

J.Wang：“固体聚合物电解质膜上键合的金属电极（SPE）－VI.钼改性Pt－SPE电极上的甲醇氧化”《电化学学报》35。323-328（1990）

M.Watanabe: "The use of thin films of sulphonated fluoroーpolymers for improvements in the activity and durability of Pt electroーcatalysts for methanol electrooxedation" J.Electroanal.Chem.284. 511-515 (1990)

M.Watanabe：“使用磺化含氟聚合物薄膜来提高甲醇电氧化的 Pt 电催化剂的活性和耐久性”J.Electroanal.Chem.284 (1990)。

K.Uosaka: "Surface morphology and reactivity of the Pt-SPE electrode:SEM,STM and electrochemical characterization" J.Electroanalytical Chemistry. 27. 275-281 (1980)

K.Uosaka：“Pt-SPE 电极的表面形态和反应性：SEM、STM 和电化学表征”J.Electroanalytical Chemistry。

K. Shimazu, R. Inaka, H. Kata: "Enhancement of the ctalytic activity of Pt microparticales dispersed in Nafion-coated electrodes for the oxidation of methanol by RF-plasma treatment" J. Electroanal. Chem. 284,. 523-529 (1990)

K. Shimazu、R. Inaka、H. Kata：“通过射频等离子体处理增强分散在 Nafion 涂层电极中的 Pt 微粒的催化活性，用于氧化甲醇”J. Electroanal。

S. Ye, K. Sugimura and H. Kita: "Structure insensitive hydrogen electrode reaction and structure sensiive adsorbed hydrogen on Pt single crystal in acid solution" J. Electroanal. Chem.

S. Ye、K. Sugimura 和 H. Kita：“酸性溶液中结构不敏感的氢电极反应和 Pt 单晶上结构敏感的吸附氢”J. Electroanal。