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Nano-structured Platinum-based Catalysts for the Complete Oxidation of Ethylene Glycol and Glycerol.

机译：纳米结构的铂基催化剂，用于乙二醇和甘油的完全氧化。

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摘要

Direct alcohol fuel cells are a viable alternative to the traditional hydrogen PEM fuel cell. Fuel versatility, integration with existing distribution networks, and increased safety when handling these fuels increases their appeal for portable power applications. In order to maximize their utility, the liquid fuel must be fully oxidized to CO2 so as to harvest the full amount of energy. Methanol and ethanol are widely researched as potential fuels to power these devices, but methanol is a toxic substance, and ethanol has a much lower energy density than other liquids such as gasoline or glucose. Oxidation of complex fuels is difficult to realize, due to difficulty in breaking carbon-carbon bonding and poisoning of the catalysts by oxidative byproducts. In order to achieve the highest efficiency, an anode needs to be engineered in such a way as to maximize activity while minimizing poisoning effects of reaction byproducts. We have engineered an anode that uses platinum-based catalysts that is capable of completely oxidizing ethylene glycol and glycerol in neutral and alkaline media with little evidence of CO poisoning. We have constructed a hybrid anode consisting of a nano-structured PtRu electrocatayst with an NAD-dependent alcohol dehydrogenase for improved oxidation of complex molecules.;A nano-structured PtRu catalyst was used to oxidize ethylene glycol and glycerol in neutral media. In situ infrared spectroscopy was used to verify complete oxidation via CO2 generation. There was no evidence of poisoning by CO species. A pH study was performed to determine the effect of pH on oxidative current. The peak currents did not trend at 60 mV/pH unit as would be expected from the Nernst equation, suggesting that adsorption of fuel to the surface of the electrode is not an electron-transfer step.;We synthesized nano-structured PtRu, PtSn, and PtRuSn catalysts for oxidation of ethylene glycol and glycerol in alkaline media. The PtRu electrocatalyst the highest oxidative currents and highest stability compared to a nano-structured platinum, PtSn, and PtRuSn catalyst. In situ infrared spectroscopy showed complete oxidation of each fuel occurred by the presence of CO 2, with very little poisoning CO species present.;In order to increase oxidative performance in neutral media, a hybrid anode based on nano-structured PtRu and a NAD-dependent alcohol dehydrogenase for the oxidation of ethanol and ethylene glycol was developed. Steady state polarization showed that the hybrid anode had higher current densities than the enzyme or the PtRu electrocatalyst alone. The hybrid anode had higher current densities at concentrations up to 3 M while oxidizing ethanol and ethylene glycol.;The catalyst synthesis, characterization, and experimental results demonstrate the feasibility of fuel cells that can oxidize higher order fuels that platinum based catalysts or enzymes cannot oxidize alone. The cooperative mechanism from co-catalysis using inorganic and organic catalysts will allow for deep oxidation and improved power generation.
机译：直接酒精燃料电池是传统氢PEM燃料电池的可行替代品。燃料的多功能性，与现有配电网络的集成以及在处理这些燃料时提高的安全性增加了其在便携式电源应用中的吸引力。为了最大程度地发挥其效用，必须将液体燃料完全氧化为CO2，以收集全部能量。广泛研究了甲醇和乙醇作为为这些设备提供动力的潜在燃料，但是甲醇是有毒物质，并且乙醇的能量密度比汽油或葡萄糖等其他液体低得多。由于难以破坏碳-碳键并难以通过氧化副产物使催化剂中毒，因此难以实现复杂燃料的氧化。为了获得最高效率，需要以使活性最大化同时最小化反应副产物的中毒作用的方式设计阳极。我们设计了一种使用铂基催化剂的阳极，该催化剂能够在中性和碱性介质中完全氧化乙二醇和甘油，而几乎没有CO中毒的迹象。我们构建了一个杂化阳极，该杂化阳极由纳米结构的PtRu电催化剂与NAD依赖的醇脱氢酶组成，可改善复杂分子的氧化。纳米结构的PtRu催化剂用于在中性介质中氧化乙二醇和甘油。原位红外光谱用于验证通过CO2产生的完全氧化。没有证据表明一氧化碳会中毒。进行了pH研究以确定pH对氧化电流的影响。如能斯特方程所预期的那样，峰值电流在60 mV / pH单位处没有趋势，这表明燃料在电极表面的吸附不是电子转移步骤。我们合成了纳米结构的PtRu，PtSn，和PtRuSn催化剂，用于在碱性介质中氧化乙二醇和甘油。与纳米结构的铂，PtSn和PtRuSn催化剂相比，PtRu电催化剂具有最高的氧化电流和最高的稳定性。原位红外光谱表明，每种燃料都因存在CO 2而发生了完全氧化，几乎没有中毒的CO物种。为了提高在中性介质中的氧化性能，基于纳米结构PtRu和NAD-的混合阳极开发了用于乙醇和乙二醇氧化的依赖型醇脱氢酶。稳态极化表明，杂化阳极比单独的酶或PtRu电催化剂具有更高的电流密度。杂化阳极在氧化乙醇和乙二醇的同时，在高达3 M的浓度下具有更高的电流密度。催化剂的合成，表征和实验结果表明，燃料电池可以氧化铂基催化剂或酶无法氧化的高级燃料的可行性。单独。使用无机和有机催化剂进行共催化的协同机理将有助于深度氧化并改善发电。

著录项

  • 作者

    Falase, Akinbayowa.;

  • 作者单位

    The University of New Mexico.;

  • 授予单位 The University of New Mexico.;
  • 学科 Chemistry Organic.;Engineering General.;Engineering Chemical.;Nanoscience.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 149 p.
  • 总页数 149
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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