tailieunhanh - Enhanced photocatalytic activity of porous nanostructed TiO2 thin film prepared by Sol-Gel process

TiO2 thin film with nanoporous structure are prepared from colloidal suspension containing polyethylen glycol (PEG) via Sol-Gel method. The effect of PEG addition to the precursor solution on the surface structures and photocatalytic activity of the resultant thin films are studied. The larger the amount of PEG added to to the precursor solution, the larger the size and number of pores produced in the resultant films when PEG added to the gel films decomposed completely during heat-treatment. The photocurrent of such porous thin film is found to increase with increasing amount of PEG up to 30% weigh of TiO2. Photocatalytic degradation experiments show that eosin, methyl orange is efficiently decolorized in the presence of the TiO2 films by exposing its aqueous solution to UV light and the suitable surface structures remarkably enhance the photocatalytic activity of TiO2 films. | Journal of Chemistry Vol. 42 2 P. 1 - 4 2004 ENHANCED PHOTOCATALYTIC ACTIVITY OF POROUS NANOSTRUCTED TIO2 THIN FILM PREPARED BY SOL-GEL PROCESS Received 25-6-2003 T. T. DUC1 T. X. HQAI1 N. T. HUE2 N. L. LAM1 N. T. TINH1 institute of Applied Physics and Scientific Instrument VAST institute of Chemistry VAST ABSTRACT TiO2 thin film with nanoporous structure are prepared from colloidal suspension containing polyethylen glycol PEG via Sol-Gel method. The effect of PEG addition to the precursor solution on the surface structures and photocatalytic activity of the resultant thin films are studied. The larger the amount of PEG added to to the precursor solution the larger the size and number of pores produced in the resultant films when PEG added to the gel films decomposed completely during heat-treatment. The photocurrent of such porous thin film is found to increase with increasing amount of PEG up to 30 weigh of TiO2. Photocatalytic degradation experiments show that eosin methyl orange is efficiently decolorized in the presence of the TiO2 films by exposing its aqueous solution to UV light and the suitable surface structures remarkably enhance the photocatalytic activity of TiO2 films. 1. INTRODUCTION In recent years one of the most active areas in heterogeneous photocatalysis is environmental remendiation with the photocatalysis. Many organic pollutants can be degraded and ultimately mineralized using TiO2 photocatalysts under UV irradiation 1 . Photocatalytic chemical reactions occurring on the surface of semiconductor materials depend on the process which start from the absorption of light and results in attainment of photogenerated electrons and holes in the surface. The illuminated semiconductor surface is regarded as a producer of hydroxyl radicals OH. These and other highly oxidizing initial products of this indirect photochemical reaction go on to attack oxidizable contaminants. The current bottleneck in photocatalysis lies in its low quantum yield which .