Model catalyst studies of SMSI and the role of D-electrons in chemisorption and catalysis. Progress report, January 15, 1985-January 14, 1986

Electron spectroscopic studies of the surface composition, electronic structure and chemisorption properties of model Rh/TiO2 catalysts fabricated on well characterized single-crystal supports have provided evidence that argues strongly against the simple charge transfer model of strong metal-support interaction that involves the transfer of electrons from surface Ti3+ ions that are created by high temperature reduction. The presence of surface Ti3+ ions does appear to be necessary in order to facilitate the migration of sub-oxides over the catalyst particles in the SMSI state, but hydrogen is not necessary if Ti3+ defect sites exist prior to high temperature annealing. A newly constructed electron beam evaporation source is now being used for in situ deposition of Rh onto TiO2 supports, giving greater control over catalyst loading and particle size. TEM studies of catalyst morphology, performed in parallel with the electron spectroscopic studies, are continuing. 3 figs