Photocatalytic degradation of methylene blue by TiO2-Cu thin films: Theoretical and experimental study
Nenhuma Miniatura disponível
Data
2010-12-15
Autores
Carvalho, Hudson W. P. [UNESP]
Batista, Ana P. L.
Hammer, Peter [UNESP]
Ramalho, Teodorico C.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Elsevier B.V.
Resumo
In this work the effect of doping concentration and depth profile of Cu atoms on the photocatalytic and surface properties of TiO2 films were studied. TiO2 films of about 200 nn thickness were deposited on glass substrates on which a thin Cu layer (5 nm) was deposited. The films were annealed during 1 s to 100 degrees C and 400 degrees C, followed by chemical etching of the Cu film. The grazing incidence X-ray fluorescence measurements showed a thermal induced migration of Cu atoms to depths between 7 and 31 nm. The X-ray photoelectron spectroscopy analysis detected the presence of TiO2, Cu2O and Cu-0 phases and an increasing Cu content with the annealing temperature. The change of the surface properties was monitored by the increasing red-shift and absorption of the ultraviolet-visible spectra. Contact angle measurements revealed the formation of a highly hydrophilic surface for the film having a medium Cu concentration. For this sample photocatalytic assays, performed by methylene blue discoloration, show the highest activity. The proposed mechanism of the catalytic effect, taking place on Ti/Cu sites, is supported by results obtained by theoretical calculations. (C) 2010 Elsevier B.V. All rights reserved.
Descrição
Palavras-chave
Photocatalysis, TiO2, Methylene blue, Cu, XPS
Como citar
Journal of Hazardous Materials. Amsterdam: Elsevier B.V., v. 184, n. 1-3, p. 273-280, 2010.