Photocatalytic activity of Ta2O5 photocatalysts decorated on SiO2 nanoparticles

ENVR 170

Ramesh Chandrasekharan, rchandra@uiuc.edu1, Nicholas Ndiege, ndiege@uiuc.edu2, Bolutife Bambgoye1, William N. Harris III, determined83@hotmail.com3, Jessica Lucido, jlucido2@uiuc.edu1, Adarsh Radadia2, Mark A. Shannon, mshannon@uiuc.edu1, and Richard I. Masel, r-masel@uiuc.edu4. (1) Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green St., Urbana, IL 61801, (2) Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews, 294 Roger Adams Laboratory, 42-6 CLSL, MC 712, Urbana, IL 61820, (3) Department of Chemistry, Clark Atlanta Univeristy, 223 James P. Brawley Dr. S.W, Atlanta, GA 30314, (4) Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Room 294, Roger Adams Lab, 600 South Mathews Avenue, Urbana, IL 61801
Ta2O5 is a photocatalyst with an energy bandgap of ~4eV and can be used to decontaminate water. Similar to TiO2, the photoreaction rate for Ta2O5 drops with the electron-hole recombination rate and is also dependent on the surface area and coverage of the pollutant. To lower the electron-hole recombination and increase pollutant adsorption, SiO2 nanoparticles with high surface area were coated with Ta2O5 using a sol-gel technique. This study reports on the photoactivity of these decorated photocatalysts as a function of the photocatalyst loading on top of the SiO2. The photoactivity and the mechanism for these decorated photocatalysts were measured using a flow through setup where the contaminated water (methylene blue or methanol) flows through a photocatalyst bed. Radical quenchers such as propanol and photoelectrical measurements are used to understand the mechanism of the photoreactions. It was observed that the photocatalytic rate per unit mass of photocatalyst was enhanced for the decorated photocatalysts as compared to pure Ta2O5. The enhanced photoactivity can be attributed to lower electron hole recombination along with increased adsorption of the pollutants.
 

Advances in Abiotic Transformation Processes for Micropollutants in Drinking Water and for Sourcewater Protection
8:30 AM-12:10 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 237, Oral

Division of Environmental Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008