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首页> 外文学位 >Self-directing organometallic deposition of ruthenium: Preparation, characterization and evaluation of bimetallic, ruthenium adatom modified platinum surfaces for the electrooxidation of methanol in direct methanol fuel cells.
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Self-directing organometallic deposition of ruthenium: Preparation, characterization and evaluation of bimetallic, ruthenium adatom modified platinum surfaces for the electrooxidation of methanol in direct methanol fuel cells.

机译：钌的自指导有机金属沉积：直接甲醇燃料电池中甲醇电氧化的双金属，钌原子原子修饰的铂表面的制备，表征和评估。

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摘要

State of the art direct methanol fuel cells use Pt-Ru particles as anode electrocatalysts for the oxidation of methanol. There are two longstanding difficulties with evaluating such catalysts; first, there are no proven methods to measure their specific surface areas (number of active sites); and second, there are no proven methods to measure the surface ratio of Pt to Ru on black (rough) Pt-Ru surfaces or particles. Further, the reported methods to prepare such catalysts do not have demonstrable control over these parameters, and surface segregation may occur during the high temperature stages of the preparation. As a result of these difficulties, the optimum surface composition and chemical state of such catalysts is still under investigation nearly 40 years after their discovery. An organometallic chemistry approach to this problem was chosen. It was found that black Pt (as a gauze or as a powder) effects the hydrogenation (1 atm, −40°C, in hexanes) of (1,5-cyclooctadiene)Ru(C 3H5)2 to result in Ru adatoms (Ruad) adsorbed by the Pt surface and the concomitant formation of cyclooctane and propane. By monitoring the reaction at low temperatures using gas chromatography or UV-Vis spectrophotometry, real time control over both the number of surface equivalents of Ruad deposited on Pt, and over the activity of the resulting Pt-Ruad surfaces was realized. This reaction was used to prepare a series of blacked Pt-Ruad gauzes and black Pt-Ru ad powders of reasonably defined surface areas and surface compositions. The activities of these gauzes and powders towards the electrooxidation of methanol under typical operating conditions for a direct methanol fuel cell were determined. Remarkably, the black Pt-Ruad powders were stable towards hot pressing into Nafion® membranes and towards use in prototype direct methanol fuel cells operating at 90°C. The optimum surface composition for operation in direct methanol fuel cells under these conditions was determined.
机译：直接甲醇燃料电池的现有技术使用Pt-Ru颗粒作为用于甲醇氧化的阳极电催化剂。评估这类催化剂有两个长期的困难；首先，没有经过验证的方法来测量其比表面积（活性部位的数量）；其次，还没有可靠的方法来测量黑色（粗糙）Pt-Ru表面或颗粒上的Pt与Ru的表面比率。此外，所报道的制备这种催化剂的方法对这些参数没有明显的控制，并且在制备的高温阶段可能发生表面偏析。由于这些困难，发现这种催化剂近40年后，仍在研究这种催化剂的最佳表面组成和化学状态。选择了有机金属化学方法来解决这个问题。发现黑色Pt（作为纱布或粉末）会影响（1,5-环辛二烯）Ru（C 3 H（1 atm，-40°C，在己烷中）的氢化 5 ） 2 导致Ru原子（Ru ad ）被Pt表面吸附，并同时形成环辛烷和丙烷。通过使用气相色谱法或紫外可见分光光度法在低温下监控反应，可以实时控制沉积在Pt上的Ru ad 的表面当量数以及生成的Pt-Ru的活性实现了 ad 表面。该反应用于制备一系列具有合理定义的表面积和表面组成的黑色Pt-Ru ad 丝网和黑色Pt-Ru ad 粉末。在直接甲醇燃料电池的典型操作条件下，测定了这些网纱和粉末对甲醇电氧化的活性。值得注意的是，黑色Pt-Ru ad 粉末在热压到Nafion®super膜中和在90°C操作的原型直接甲醇燃料电池中均稳定。确定了在这些条件下在直接甲醇燃料电池中运行的最佳表面组成。

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  • 作者

    Lee, Christopher Edward.;

  • 作者单位

    University of Alberta (Canada).;

  • 授予单位 University of Alberta (Canada).;
  • 学科 Chemistry Organic.; Energy.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 132 p.
  • 总页数 132
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 有机化学;能源与动力工程;
  • 关键词

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