CENTRO DE INVESTIGACION Y DESARROLLO EN CIENCIAS APLICADAS "DR. JORGE J. RONCO"
Unidad Ejecutora - UE
congresos y reuniones científicas
One-pot synthesis of mesoporous H4SiW12O40 /TiO2 composites using sol-gel reactions
VANESA M. FUCHS,; EDGARDO L. SOTO,; MIRTA N. BLANCO,; LUIS R. PIZZIO
Congreso; IX Europacat Congress; 2009
Among several photocatalysts, TiO2 (in anatase phase) has been the most widely used because it is easily available, inexpensive, non-toxic, and shows relatively high chemical stability. The photocatalytic activity of titania is influenced by the crystal structure, crystalinity, surface area, band gap, porosity and surface hydroxyl group density . However, the shortcomings of conventional powder catalysts include low efficiency of light use, and difficulty in the separation after reaction. Hole-electron recombination and low surface area are considered among the most important disadvantages of TiO2 that result in low photocatalytic activity in practical applications. Therefore, the photocatalytic activity of TiO2 based catalysts can be improved by separation of the electrons and holes and the increase of the surface area. It is known that doping with suitable metal ions allows extending the light absorption of large band-gap semiconductors to the visible region . Heteropolyoxometalates (POMs) have been used to modify TiO2 in order to reduce the charge recombination. They have been added to TiO2 suspensions , incorporated into TiO2 colloids or anchored to TiO2 by chemical interactions . In addition, the incorporation of POMs into titania matrix can improve the density of catalysts and makes easier to separate them from heterogeneous reaction systems for recycling. Titania with large surface area was reported to be suitable to obtain high catalytic performance, and can be synthesized using urea as low cost template via sol-gel reactions. We present here the preparation, characterization and evaluation in methyl orange catalytic photodegradation of mesoporous titania obtained using urea as low cost pore-forming agent, via HCl catalyzed sol-gel reactions, modified with tungstosilicic acid (TSA).