Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst
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Case Western Reserve University School of Graduate Studies / OhioLINK
2008
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=case1209692060 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-case12096920602021-08-03T05:32:35Z Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst Pelsozy, Michael C. Chemical Engineering Chemistry Materials Science Hydrogen peroxide Proton Exchange membrane fuel cell TEM The production and prevalence of H<sub>2</sub>O<sub>2</sub> in a proton exchange membrane fuel cell(PEMFC) is concern due to its purported role in the long term durability of the fuelmembrane. Several approaches to the detection of H<sub>2</sub>O<sub>2</sub> using microelectrodes insertedinto working PEMFCs were explored. Au and Pt microelectrodes were used to carry outvarious electrochemical methods to probe reactions in situ at steady state. Substantialdifficulties were encountered in deploying these methods. A detailed study of variousaspects of both Au and Pt microelectrodes in operating cells revealed a number ofinteresting phenomena as well as difficulties in peroxide detection in the presence ofhydrogen cross-over. Interactions between hydrogen and H<sub>2</sub>O<sub>2</sub> in the presence of theelectrode surface leads to enhanced oxidation currents at surprisingly low potentials onAu. Steady state and transient voltammetry exhibit different behavior on both Au and Ptin the -OH adsorption region, possibly due to slow catalytic removal of the Au-OH andPt-OH films by hydrogen. Careful calibration of the response to peroxide in the presenceof hydrogen in a fuel cell configuration revealed that H<sub>2</sub>O<sub>2</sub> can be detected at Pt underfavorable conditions. However, in an operating fuel cell, H<sub>2</sub>O<sub>2</sub> making it to the probeelectrode is insufficient to yield a signal under the conditions of testing.Also, the transport of H<sub>2</sub>O<sub>2</sub> in a PEMFC membrane material was studied. Thiswas done by measuring the diffusion coefficient of H<sub>2</sub>O<sub>2</sub> in recast a Nafion<sup>®</sup> film on a Ptrotating disk electrode (RDE).Finally, the PEMFC catalyst most widely deployed, nanometer sized Pt particles,was investigated using methods of high-resolution transmission electron microcopy(HRTEM). Attempts were made to obtain images of these particles eliminating orsubstantially reducing the effects of artifacts arising from the microscope optics. Theexperimental difficulties in obtaining such images is demonstrated and discussed. Animage of a Pt particle substantially reduced in artifact due to the use of aberrationcorrected HRTEM is used order to show that the displacement of atom columnscomprising the particle exists. In the particular case studied the displacement causes anexpansion of the particle on the order of 3% - 5% and is attributed to interaction witha neighboring particle via van der Waals forces. 2008-05-07 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1209692060 http://rave.ohiolink.edu/etdc/view?acc_num=case1209692060 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Chemical Engineering Chemistry Materials Science Hydrogen peroxide Proton Exchange membrane fuel cell TEM |
| spellingShingle |
Chemical Engineering Chemistry Materials Science Hydrogen peroxide Proton Exchange membrane fuel cell TEM Pelsozy, Michael C. Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst |
| author |
Pelsozy, Michael C. |
| author_facet |
Pelsozy, Michael C. |
| author_sort |
Pelsozy, Michael C. |
| title |
Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst |
| title_short |
Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst |
| title_full |
Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst |
| title_fullStr |
Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst |
| title_full_unstemmed |
Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its Catalyst |
| title_sort |
investigation of hydrogen peroxide production and transport in a proton exchange membrane fuel and the atom resolved micro-characterization of its catalyst |
| publisher |
Case Western Reserve University School of Graduate Studies / OhioLINK |
| publishDate |
2008 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=case1209692060 |
| work_keys_str_mv |
AT pelsozymichaelc investigationofhydrogenperoxideproductionandtransportinaprotonexchangemembranefuelandtheatomresolvedmicrocharacterizationofitscatalyst |
| _version_ |
1719421529094094848 |