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AutorSeidel, Yvonne Evadc.contributor.author
Aufnahmedatum2016-03-15T06:23:35Zdc.date.accessioned
In OPARU verfügbar seit2016-03-15T06:23:35Zdc.date.available
Jahr der Erstellung2010dc.date.created
ZusammenfassungThe 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
Spracheendc.language.iso
Verbreitende StelleUniversität Ulmdc.publisher
LizenzStandard (Fassung vom 01.10.2008)dc.rights
Link zum Lizenztexthttps://oparu.uni-ulm.de/xmlui/license_v2dc.rights.uri
SchlagwortGlassy carbondc.subject
SchlagwortModel electrodesdc.subject
SchlagwortNanostructuringdc.subject
SchlagwortTransport effectsdc.subject
DDC-SachgruppeDDC 540 / Chemistry & allied sciencesdc.subject.ddc
LCSHElectrocatalysisdc.subject.lcsh
LCSHPlatinumdc.subject.lcsh
TitelStability and electrocatalytical properties of nanostructured Pt / glassy carbon model electrodesdc.title
RessourcentypDissertationdc.type
DOIhttp://dx.doi.org/10.18725/OPARU-1878dc.identifier.doi
PPN334900077dc.identifier.ppn
URNhttp://nbn-resolving.de/urn:nbn:de:bsz:289-vts-74620dc.identifier.urn
GNDElektrokatalysedc.subject.gnd
GNDNanostrukturdc.subject.gnd
FakultätFakultät für Naturwissenschaftenuulm.affiliationGeneral
Datum der Freischaltung2010-12-09T14:42:20Zuulm.freischaltungVTS
Peer-Reviewneinuulm.peerReview
Signatur DruckexemplarZ: J-H 13.860; W: W-H 12.328uulm.shelfmark
DCMI MedientypTextuulm.typeDCMI
VTS-ID7462uulm.vtsID
KategoriePublikationenuulm.category


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