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AuthorSeidel, Yvonne Evadc.contributor.author
Date of accession2016-03-15T06:23:35Zdc.date.accessioned
Available in OPARU since2016-03-15T06:23:35Zdc.date.available
Year of creation2010dc.date.created
AbstractThe results presented in this thesis mediate mesoscopic transport effects induced by the electrode morphology and reaction characteristics such as activity and selectivity in electrocatalytic reactions. The application of nanostructured Pt/glassy carbon surfaces representing simplified, well-defined and reliable two dimensional model systems of the commonly used real carbon-supported Pt/C catalysts, offered the possibility to vary the transport conditions arbitrarily and to correlate the results, respectively. It is demonstrated that these model systems are ideally suited for studying mass transport processes and their effect on the kinetics of electrocatalytic reactions. Transport of reactants to the electrode not only affects the reaction rate, by means of a "mass transport limited current", but may also alter the overall reaction behaviour, in particular its selectivity and hence the product distribution in reactions leading to more than one product. The measurements reveal a distinct variation in the selectivity of electrocatalytic reactions such as the oxygen reduction or the methanol oxidation reaction with (i) increasing separation of the Pt nanostructures and therefore active Pt sides and (ii) with increasing electrolyte flow rate. Based on these findings, the "desorption-readsorption-reaction" concept was introduced. This reaction model explains the observations by the readsorption probability of reactive incomplete reaction products on neighbouring active Pt sites after desorption into the electrolyte and therefore the chance of further reaction towards the final reaction products. The readsorption probability strongly depends on (i) the separation of the Pt nanostructures and (ii) the electrolyte flow rate and hence the thickness of the stagnant diffusion layer above the electrode surface. Hence, the readsorption probability decreases with increasing interparticle distances or with increasing electrolyte flow rate resulting in a thinner diffusion layer.dc.description.abstract
Languageendc.language.iso
PublisherUniversität Ulmdc.publisher
LicenseStandard (Fassung vom 01.10.2008)dc.rights
Link to license texthttps://oparu.uni-ulm.de/xmlui/license_v2dc.rights.uri
KeywordGlassy carbondc.subject
KeywordModel electrodesdc.subject
KeywordNanostructuringdc.subject
KeywordTransport effectsdc.subject
Dewey Decimal GroupDDC 540 / Chemistry & allied sciencesdc.subject.ddc
LCSHElectrocatalysisdc.subject.lcsh
LCSHPlatinumdc.subject.lcsh
TitleStability and electrocatalytical properties of nanostructured Pt / glassy carbon model electrodesdc.title
Resource typeDissertationdc.type
DOIhttp://dx.doi.org/10.18725/OPARU-1878dc.identifier.doi
PPN642166102dc.identifier.ppn
URNhttp://nbn-resolving.de/urn:nbn:de:bsz:289-vts-74620dc.identifier.urn
GNDElektrokatalysedc.subject.gnd
GNDNanostrukturdc.subject.gnd
FacultyFakultät für Naturwissenschaftenuulm.affiliationGeneral
Date of activation2010-12-09T14:42:20Zuulm.freischaltungVTS
Peer reviewneinuulm.peerReview
Shelfmark print versionZ: J-H 13.860; W: W-H 12.328uulm.shelfmark
DCMI TypeTextuulm.typeDCMI
VTS-ID7462uulm.vtsID
CategoryPublikationenuulm.category


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