Please use this identifier to cite or link to this item: http://hdl.handle.net/10773/19243
Title: Phase composition, crystal structure and microstructure of silver and tungsten doped TiO2 nanopowders with tuneable photochromic behaviour
Author: Tobaldi, D. M.
Pullar, R. C.
Gualtieri, A. F.
Seabra, M. P.
Labrincha, J. A.
Keywords: X-RAY-DIFFRACTION
VISIBLE-LIGHT PHOTOCATALYSIS
SURFACE-PLASMON RESONANCE
OPTICAL-PROPERTIES
TITANIUM-DIOXIDE
METAL NANOPARTICLES
MULTICOLOR PHOTOCHROMISM
RUTILE TRANSFORMATION
HYDROGEN-PRODUCTION
THIN-FILMS
Issue Date: 2013
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Abstract: Titanium dioxide exists in a large number of polymorphs, the most common ones being, in order of abundance, rutile, anatase and brookite. Recently, there has been an increasing degree of attention on TiO2, due to its photocatalytic and antibacterial properties. In this work, titania nanopowders synthesized via an aqueous sol gel method were modified with silver and/or tungsten, with potential application as photocatalysts and antibacterial agents. The dried gels were thermally treated at two temperatures, and the occurrence of amorphous phase-in both dried and calcined gels-was obtained using the Rietveld method. In powders calcined at 600 degrees C, the crystal structure of rutile was determined with the Rietveld method on the full profile fitting of the X-ray powder diffraction patterns, while microstructural information was achieved by means of Williamson-Hall plots and line broadening analysis methods. The photochromic property of the Ag and W/Ag modified samples-when subjected to both UV- and visible-light irradiation and for different time exposures-was also investigated via UV-Vis spectroscopy. Powders were shown to possess a tuneable photochromism due to the surface plasmon resonance of the added silver, depending on the firing temperature, light (and time) exposure, and on whether or not tungsten was present in the nanopowders. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Peer review: yes
URI: http://hdl.handle.net/10773/19243
DOI: 10.1016/j.actamat.2013.05.041
ISSN: 1359-6454
Publisher Version: 10.1016/j.actamat.2013.05.041
Appears in Collections:CICECO - Artigos



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