HR: 09:45h
AN: B31D-08    [Abstracts]
TI: Photocatalyzed Reduction of Carbon Dioxide
AU: * Mill, T -
EM: ted.mill@sri.com
AF: SRI, 333 Ravenswood Ave, Menlo Park, CA 94025 United States
AU: Tungudomwongsa, H
EM: tungudom@stanford.edu
AF: Environmental Engineering Department, Stanford University, Stanford, CA 94307 United States
AB: We investigated the photochemical reduction of CO2 in aqueous solution to form C1 products using a variety of oxide semiconductors and UV light in the solar region above 300 nm. Oxide semiconductors TiO2 and SrTiO3 as well as these semiconductors modified with Pt, Cr, Sb, Fe3O4 or Fe(CN)6 were used. Analyses for C1 and some C2 products were made, but we found only trace quantities of formate and acetate. The quantum efficiency of SrTiO3 for forming formate and acetate is about 0.1% or less, with a combined quantum and spectral efficiency of less than 0.01%. Semiconductors modified to increase absorption of visible light exhibited no enhanced efficiency. However, Pt/TiO2 produces twice as much formate and acetate as TiO2. Re-oxidation of formate may be limiting efficiency and new design strategies are needed if a useful process is to be developed Preliminary estimates give the size of a perfectly efficient solar CO2 photoreduction unit scaled for a 1000 MW coal-fired electricity plant to be as small as 2 to 3 km2.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0428 Carbon cycling (4806)
SC: Biogeosciences [B]
MN: Fall Meeting 2005