Analytical Sciences

Abstract − Analytical Sciences, 17(1), 125 (2001).

Characterization of Surface and Photooxidative Properties of Supported Metal Oxide Photocatalysts Using Solid-State NMR
Sarah PILKENTON, Weizong XU, and Daniel RAFTERY 
H. C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393, U.S.A.
In situ solid-state NMR (SSNMR) methodologies have been used to investigate the surface properties and photooxidative reactivities of a number of metal oxide photocatalysts. Adsorption of ethanol on single monolayers of TiO2, SnO2, V2O5, and WO3 supported on porous Vycor glass results in the formation of hydrogen-bonded ethanol species and metal-bound ethoxide species. The chemical shift of the metal-bound ethoxide species varies with the metal oxide catalyst while the chemical shift of the hydrogen-bonded species is independent of the metal oxide. X-ray powder diffraction, UV-VIS spectroscopy, and SSNMR investigations of ethanol adsorption show that increasing the number of monolayers of TiO2 on the Vycor surface changes the morphology of the catalyst from amorphous at a single monolayer coverage to anatase at a four monolayer coverage. The rate of photocatalytic oxidation of ethanol, acetone, and 2-propanol also increases with increasing TiO2 monolayer coverage.