Show simple item record

dc.contributor.advisorNorton, M. Grant
dc.creatorTurba, Timothy
dc.date.accessioned2012-04-27T20:45:31Z
dc.date.available2012-04-27T20:45:31Z
dc.date.issued2011
dc.identifier.urihttp://hdl.handle.net/2376/3535
dc.descriptionThesis (Ph.D.), School of Mechanical and Materials Engineering, Washington State Universityen_US
dc.description.abstractNanoparticle gold is of interest for a wide array of applications including catalysis, gas sensing, and light absorption for color filters and optical switches. Many of these applications are dependent upon the particles having sizes <5nm. In this paper, the thermal stability of nanoparticle gold is evaluated. Unsupported gold nanoparticles can grow (and in some cases double their size) even at room temperature. An important approach to stabilizing gold nanoparticles is through an interaction with a suitable substrate support material. Semiconductor substrates such as GaN are important supports for gold nanoparticles for applications such as sensors, but GaN does not provide a significant stabilizing effect at high temperatures. This paper covers a number of different substrate materials and in particular shows that for some substrates, such as SiO2, gold nanoparticles can be stable at temperatures up to 500°C, which is significantly above the Tammann temperature for bulk gold (395°C). In this dissertation, gold nanoparticles are shown to have complete stability on aluminum-supported silica nanosprings at 550°C in air. This stability window is one of the highest reported for nanoparticle gold and potentially enables a number of applications for this highly active catalyst. X-ray photoelectron spectroscopy measurements were performed before and after heating to 550°C to determine the nature of the interaction between gold and SiO2. A 1.2 eV drop in gold 4f binding energy after heating signified a shift to anionic gold particles, indicative of strong bonds to oxygen vacancies with neighboring Si atoms. Heating in hydrogen at 550°C resulted in a binding energy decrease of 0.4 eV due to an increased fraction of particles with decreased coordination numbers (i.e., more atoms at edges and corners). Lastly, heating gold nanoparticles in an atmosphere of 10% relative humidity at 550°C resulted in apparent encapsulation of the gold.en_US
dc.description.sponsorshipDepartment of Materials Science, Washington State Universityen_US
dc.languageEnglish
dc.rightsIn copyright
dc.rightsLimited public access
dc.rightsrestrictedAccess
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.rights.urihttp://www.ndltd.org/standards/metadata
dc.rights.urihttp://purl.org/eprint/accessRights/RestrictedAccess
dc.subjectMaterials Scienceen_US
dc.subjectBinding Energyen_US
dc.subjectGold Nanoparticlesen_US
dc.subjectOstwald Ripeningen_US
dc.subjectSilica Nanospringsen_US
dc.subjectSupporten_US
dc.subjectThermal Stabilityen_US
dc.titleThermal Stability of Supported Gold Nanoparticles
dc.typeElectronic Thesis or Dissertation


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record