resumo
Tungsten, silver and tungsten/silver co-doped titania nanopowders were synthesised via an aqueous sol-gel method. The size distribution and zeta potential of the starting sols were determined via photon correlation spectroscopy (PCS). The dried gels were thermally treated at two different temperatures, and the occurrence of amorphous phase was assessed using the combined Rietveld-RIR X-ray powder diffraction method. A systematic study of the optical properties of the powders was made with diffuse reflectance spectroscopy (DRS), and the energy band gaps were calculated using the differential reflectance method; while their morphology was investigated using electron microscopy analysis (TEM). The photocatalytic activity of the samples was assessed in liquid-solid phase, under UVA-light and visible-light irradiation, monitoring the degradation of an organic dye. The influence of the phase composition, optical properties, dimensions, and specific surface area of the powders on the photocatalytic activity was thoroughly discussed. (C) 2012 Elsevier B.V. All rights reserved.
palavras-chave
PHASE-TRANSFORMATION; SILVER NANOPARTICLES; POLYCRYSTALLINE TIO2; OPTICAL-PROPERTIES; LIGHT IRRADIATION; PLASMON RESONANCE; ORGANIC-COMPOUNDS; AQUEOUS SYSTEMS; TITANIA; RUTILE
categoria
Engineering
autores
Tobaldi, DM; Pullar, RC; Gualtieri, AF; Seabra, MP; Labrincha, JA
nossos autores
David Maria Tobaldi
Investigador
João António Labrincha Baptista
Professor Catedrático
Maria Paula Seabra
Professor Auxiliar
Rob Pullar
Colaboradoragradecimentos
Authors acknowledge PEst-C/CTM/LA0011/2011 programme. M.P. Seabra and R.C. Pullar wish to thank the FCT Ciencia2008 programme for supporting this work. D.M. Tobaldi kindly acknowledges FCT for the financial support.