CENTRO DE INVESTIGACION Y DESARROLLO EN CIENCIAS APLICADAS "DR. JORGE J. RONCO"
Unidad Ejecutora - UE
congresos y reuniones científicas
Mesoporous nanospheres of tungstosilicic acid/titaniacomposites as catalysts in the photodegradation of 4-chlorophenol
JULIÁN A. RENGIFO-HERRERA; ROMINA FRENZEL; MIRTA BLANCO; LUIS PIZZIO
Congreso; 11th International Symposium: Scientific Bases for the Preparation of Heterogeneous Catalysts; 2014
The degradation of chemicals present in wastes by photocatalysis is an important issue and its study is a constantly growing field. Titanium dioxide has been the most widely used photocatalyst due to its easy availability, low cost, relatively high chemical stability, and its negligible toxicity. Several factors influence the photocatalytic activity of titania, such as the crystal structure, the crystallinity, the surface area, the porosity, the band gap energy, andthe surface hydroxyl density . Mesoporous titania with suitable properties to be used as photocatalyst was synthesized via sol-gel reactions using urea as a low-cost pore-forming agent .The most important disadvantages of titania as photocatalyst are the hole-electron recombination and low surface area, which lead to low photocatalytic activity. Therefore, the photocatalytic activity of titania-based catalysts can be improved by separation of electrons and holes, and by increasing the surface area.On the other hand, heteropolyoxometallates (POMs) were employed as effective homogeneous photocatalysts in the degradation of organic pollutants in water . Furthermore, some heteropolyoxometallates have been used as titania modifiers intending to reduce the charge recombination. They have been added to TiO2 suspensions, incorporatedinto TiO2 colloids, or anchored to TiO2 by chemical interactions. We incorporated TPA into the titania matrix during the synthesis of TiO2 gel, using urea as low-cost template in order to obtain mesoporous materials . In addition, the incorporation of POMs into the titania matrix can improve the density of the catalysts, thus facilitating their separation from heterogeneous reaction systems in order to reuse them.We present here the preparation and characterization of mesoporous titania directly modified with tungstosilicic acid (TSA), using urea as a low-cost pore-forming agent, via HCl-catalyzed sol-gel reactions.The aim is to study the influence of some preparation conditions, such as TSA concentration and calcination temperature, on the characteristics of the tungstosilicic acid mesoporous titania nanospheres synthesized via sol?gel reactions and measured the catalytic activity of the materials in the 4-chlorophenol photodegradation.