The Pd/TiO2 and V/TiO2 prepared by a sol-gel method calcined at 500 °C for 3 h was characterized in this study. The synthesized photocatalysts were used for the photodegradation of 1,2dichloroethane (1,2-DCE). From X-ray powder diffraction data, the crystal phase presents the mixture of anatase and rutile phases, and anatase is the dominant phase. The crystallites of photocatalysts are spherical particles with a crystallite size about 10-20 nm. UV-Visible diffuse reflectance spectra of Pd/TiO2 and V/TiO2 show an increase in absorbency in the visible light region with the increasing dopant concentration. The X-ray photoelectron spectroscopy results indicate that the doped vanadium ions should exist in the form of V 4+. From 1,2-DCE photocatalytic degradation, the performance of Pd/TiO2 is worse than that of TiO2 alone. The presence of palladium ions may increase the adsorption of byproducts adsorbed on the surface of Pd/TiO2, therefore reducing the number of available active sites for the photocatalytic reaction. Furthermore, the performance of V/TiO 2 is better than that of TiO2 alone, and the optimum vanadium dopant concentration is 0.01 mol%. V4+ can act as both holes and electron traps to reduce the recombination rate of electron-hole pairs and enhance the photocatalytic activity. From surface area data, he surface areas of Pd/TiO2 or V/TiO2 are similar to those of TiO 2, and the photocatalytic activity of V/TiO2 with low levels of vanadium dopant is better than that of TiO2 alone. From SEM images and EDS results, the deactivation phenomena occur when the byproducts are irreversibly chemisorbed to the active sites of photocatalysts. The intermediates of 1,2-DCE photocatalytic degradation include C2H 5CI, CH2CI2, and HCl.
|Number of pages||10|
|Publication status||Published - 2007 Nov 19|
|Event||Annual Conference of the Canadian Society for Civil Engineering 2007: Where the Road Ends, Ingenuity Begins - Yellowknife, NT, United States|
Duration: 2007 Jun 6 → 2007 Jun 9
|Other||Annual Conference of the Canadian Society for Civil Engineering 2007: Where the Road Ends, Ingenuity Begins|
|Period||07-06-06 → 07-06-09|
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