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SUMMARY:DRS\, XRD and SEM studies of the effects of metal dopants (Pt\, Au
  and Pd) on the structural and optical properties of TiO2.
DTSTART;VALUE=DATE-TIME:20110713T150000Z
DTEND;VALUE=DATE-TIME:20110713T170000Z
DTSTAMP;VALUE=DATE-TIME:20260609T124717Z
UID:indico-contribution-5267@events.saip.org.za
DESCRIPTION:Speakers: Jacob Ramodika Moloantoa (University of Limpopo)\nTi
 tania is a cheap and nontoxic polymorphic material of current interest for
  a variety of technological applications like in gas sensing and photovolt
 aic cells. Generally\, TiO2\, with a band gap of 3.2 eV\, can only be exci
 ted by a small UV fraction of solar light\, which accounts for only 3-5% o
 f the solar energy.  Various strategies have been pursued including doping
  with metallic elements (e.g. Fe) or nonmetallic elements (e.g. N) with th
 e aim of shifting the absorption into the visible range. In the present wo
 rk TiO2 was doped with platinum (Pt)\, palladium (Pd) and gold (Au) at dop
 ing levels of 5% weight\, following the standard sol-gel methods. Structur
 al characterization was carried out using scanning electron microscopy (SE
 M) and X-ray diffraction (XRD). Optical properties were studied using the 
 Diffuse Reflectance Spectroscopy (DRS). The results of the lattice paramet
 er calculations from the XRD patterns of metal loaded TiO2 are almost the 
 same as for the undoped. Doping with Pt and Pd resulted in a lower anatase
  to rutile phase transformation temperature while doping with Au did not a
 ffect the transformation temperature. SEM micrographs show that the surfac
 e contains irregular shaped particles which are the aggregation of tiny cr
 ystals for lower temperatures.  At higher temperatures (900 °C)\, we obse
 rve spheroids of metallic nanocrystals on the surface of TiO2.The reflecta
 nce spectra of the metal loaded TiO2 reveal substantial reduction in refle
 ction (i.e. they show enhanced absorption)from 400nm to the entire visible
  region.\n\nhttps://events.saip.org.za/event/7/contributions/5267/
LOCATION: Asteria
URL:https://events.saip.org.za/event/7/contributions/5267/
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