|AVS 57th International Symposium & Exhibition|
|Surface Science||Wednesday Sessions|
|Session:||Oxide Surface Structure|
|Presenter:||Z. Li, Pacific Northwest National Laboratory|
|Authors:||Z. Li, Pacific Northwest National Laboratory
Z. Zhang, Pacific Northwest National Laboratory
Y.K. Kim, Pacific Northwest National Laboratory
S. Smith, Pacific Northwest National Laboratory
F.P. Netzer, Karl-Franzens University Graz, Austria
R.J. Rousseau, Pacific Northwest National Laboratory
B.D. Kay, Pacific Northwest National Laboratory
Z. Dohnálek, Pacific Northwest National Laboratory
|Correspondent:||Click to Email|
Catalysts based on WO3 have been found to be active in a number of reactions including isomerization of alkanes and alkenes, partial oxidation of alcohols, selective reduction of nitric oxide, and metathesis of alkenes. In the present study we explore the growth of novel ordered WO3 thin films on Pt(111) via direct sublimation of monodispersed (WO3)3 clusters. The prepared films are characterized using x-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD), low energy electron diffraction (LEED), reflection-adsorption infrared spectroscopy (RAIRS), and scanning tunneling microscopy (STM). The factors that affect the WOx structure such as WO3 exposure and substrate temperature were explored. At submonolayer coverages, the as-deposited (WO3)3 clusters are partially reduced leading to chainlike tungsten oxide structures with W in (6+) and (5+) oxidation states . Higher substrate temperatures (< 800 K) lead to further reduction of deposited (WO3)3. At higher coverages, an ordered (3 × 3) structure composed of (WO3)3 trimers is observed upon 700 K deposition. The experimental findings are complemented by DFT calculations that provide further insight into the observed WO3 structures.
This research was performed in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.