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Nano-structured platinum-based catalysts for the complete oxidation of ethylene glycol and glycerol

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Please use this identifier to cite or link to this item: http://hdl.handle.net/1928/17472

Nano-structured platinum-based catalysts for the complete oxidation of ethylene glycol and glycerol

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dc.contributor.author Falase, Akinbayowa
dc.date.accessioned 2012-02-01T18:05:58Z
dc.date.available 2012-02-01T18:05:58Z
dc.date.issued 2012-02-01
dc.date.submitted December 2011
dc.identifier.uri http://hdl.handle.net/1928/17472
dc.description.abstract 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 electrocatalyst 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 gave 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 CO2, 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. en_US
dc.description.sponsorship National Science Foundation, Louis Stokes Alliances for Minority Participation (LSAMP) Program, Integrating Nanotechnology with Cell Biology and Neuroscience Integrative Graduate Education and Research Traineeship en_US
dc.language.iso en_US en_US
dc.subject Fuel Cells en_US
dc.subject Ethylene Glycol en_US
dc.subject Glycerol en_US
dc.subject Catalyst synthesis en_US
dc.subject Anode catalysts en_US
dc.subject in situ FTIR en_US
dc.subject.lcsh Fuel cells--Electrodes.
dc.subject.lcsh Ethylene glycol--Ozydation.
dc.subject.lcsh Glycerol----Ozydation.
dc.subject.lcsh Platinum catalysts.
dc.subject.lcsh Nanostructured materials.
dc.title Nano-structured platinum-based catalysts for the complete oxidation of ethylene glycol and glycerol en_US
dc.type Dissertation en_US
dc.description.degree Chemical Engineering en_US
dc.description.level Doctoral en_US
dc.description.department University of New Mexico. Dept. of Chemical and Nuclear Engineering en_US
dc.description.advisor Atanassov, Plamen
dc.description.committee-member Petsev, Dimiter
dc.description.committee-member Calabrese-Barton, Scott
dc.description.committee-member Lau, Carolin


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