COLL 465 |
| Robert J Madix and Enrique Farfan-Arribas. Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, CA 94305 |
| The reactivity of methanol, ethanol, n-propanol and isopropanol adsorbed on stoichiometric and defective TiO2(110) surfaces was studied by means of temperature programmed reaction spectroscopy and X-ray photoelectron spectroscopy. On the stoichiometric TiO2(110) surface the alcohols adsorbed dissociatively at room temperature, forming alkoxide and hydroxide groups. Approximately half of the alkoxide groups recombined at low temperature (< 500 K) with hydroxide groups to form their respective parent alcohols. Due to the creation of oxygen anion defects by hydroxide-hydroxide recombination to form water at the same temperature, alkoxide groups on the surface reacted at higher temperatures (> 500 K) to form their corresponding alkenes. The creation of oxygen anion defects by electron irradiation shifted the product distribution toward the high temperature channel, favoring production of the corresponding alkene. Two different binding sites for the alkoxide species (Ti4+ cations and bridging oxygen vacancies) are proposed to be responsible for the different reaction products. |
|
Symposium in Memory of Arthur W. Adamson
8:30 AM-11:50 AM, Thursday, April 1, 2004 Marriott -- Orange County 3, Oral
Division of Colloid and Surface Chemistry |