Fundação para a Ciência e a Tecnologia (FCT

Castanheira, Elisabete M. S.

Coutinho, Paulo J. G.

Gonçalves, Marlene B.

Universidade do Minho: RepositoriUM

TUNGSTEN OXIDE NANOPARTICLES PREPARED WITH SOFT TEMPLATING METHODS Paulo J.G. Coutinho, Marlene B. Gonçalves, Elisabete M.S. Castanheira Centro de Física, Universidade do Minho, 4710-057 Braga, Portugal pcoutinho@fisica.uminho.pt   Abstract Tungsten trioxide, WO3, has been widely used to construct electrochromic windows, optical devices, gas sensors and as photocatalyst [1]. WO3 has drawn more attention because of its high efficiency in photocatalytic degradation of organic compounds, including a large fraction of environmental toxins [2]. WO3 is suitable for application in energy renewal, energy storage and environmental cleanup, using radiation in the visible spectral region [3]. In all of these applications, the morphological characteristics of the materials, like grain size or shape, are very important and depend strongly on the preparation method [3]. In this work, WO3 nanoparticles were obtained by a soft templating method, using the aqueous nanocavities of AOT [sodium bis(2-ethyl-1-hexyl) sulfosuccinate] reverse micelles in cyclohexane (fig. 1).            Fig. 1. Preparation method of WO3       semiconductor nanoparticles.        Fig. 2. PLE (λem=425 nm) and PL (λexc=360 nm)         spectra of WO3 nanoparticles.   The photoluminescence emission (PL) and excitation (PLE) spectra of the prepared WO3 nanoparticles were measured (fig. 2) and compared with published data [4]. The prepared WO3 nanoparticles were deposited in solid substrate by the Langmuir-Blodgett technique and were used in photodegradation assays of phenol.   [1] A. Mills, S. Le Hunte, J. Photochem. Photobiol. A: Chem. 108 (1997) 1-35. [2] E. Pelizzetti, Chemosphere 17 (1998) 499-510. [3] N. Asim, S. Radiman, M.A.bin Yarmo, Mater. Lett. 61 (2007) 2652-2657. [4] M. Niederberger, M.H. Bartl, G.D. Stucky, J. Am. Chem. Soc. 124 (2002) 13642-13643.  00.51280 380 480 580λ (nm)PL intensity (a.u.) P L E P LNa2WO4 H+ ∆ WO3 

Tungsten oxide nanoparticles prepared with soft templating methods

http://repositorium.sdum.uminho.pt/bitstream/1822/13802/1/PJGCoutinho_PPTC09.pdf

Tungsten oxide nanoparticles prepared with soft templating methods

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Universidade do Minho: RepositoriUM