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dc.contributor.advisorCrooks, Richard M. (Richard McConnell)
dc.creatorMyers, Vera Sueen
dc.date.accessioned2013-07-03T20:11:09Zen
dc.date.accessioned2017-05-11T22:33:10Z
dc.date.available2017-05-11T22:33:10Z
dc.date.issued2011-12en
dc.date.submittedDecember 2011en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-12-4468en
dc.identifier.urihttp://hdl.handle.net/2152/20660en
dc.descriptiontexten
dc.description.abstractThe small size regime and bulky hydrocarbon exterior of dendrimer encapsulated nanoparticles (DENs) often make characterization of these materials a unique challenge. Here, I report on three studies utilizing the techniques of extended X-ray absorption fine structure (EXAFS) and electrochemistry to probe the properties and behavior of these materials. First, the synthesis and characterization of PdCu bimetallic nanoparticles, and Pd and Cu monometallic nanoparticles, consisting of an average of ~64 atoms is described. The bimetallic nanoparticles were prepared by co-complexation of Pd²⁺ and Cu²⁺ salts to interior functional groups of a dendrimer template followed by chemical reduction to yield DENs. EXAFS spectroscopy indicates that these particles have an alloy structure. This is a rare example of a stable nanoparticle in this size range that consists of one reactive metal and one substantially more noble metal. Second, in-situ electrochemical EXAFS is used to evaluate the structure of Pt DENs during the oxygen reduction reaction (ORR). The DENs contained an average of just 225 atoms each. The results indicate that the Pt coordination number (CN) decreases when the electrode potential is moved to positive values. The results are interpreted in terms of an ordered core, disordered shell model. The structure of the DENs is not significantly impacted by the presence of dioxygen, but other electrogenerated species may have a significant impact on nanoparticle structure. Third, the electrochemical dissolution of Cu DENs is investigated using anodic stripping voltammetry (ASV). The effect of the scan rate and Cu loading on the electrode to the stripping wave is performed. The results indicate a large, positive shift of the stripping potential for the dendrimer-metal composites, but no size-dependent changes to peak position.en
dc.format.mimetypeapplication/pdfen
dc.language.isoen_USen
dc.subjectNanoparticleen
dc.subjectDendrimeren
dc.subjectEXAFSen
dc.titleCharacterization of dendrimer encapsulated nanoparticles by extended x-ray absorption fine structure and electrochemical methodsen
dc.description.departmentChemistryen
dc.date.updated2013-07-03T20:11:10Zen
dc.embargo.terms12/1/2012en
dc.embargo.lift12/1/2012en


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