Surface characterization of metal oxide overlayers

Conference · Mon Aug 01 00:00:00 EDT 1988

OSTI ID:6712644

Williams, K J; Levin, M E; Salmeron, M; Bell, A T; Somorjai, G A

The present paper discusses the characterization of titania overlayers deposited on the surface of a polycrystalline Rh foil and a Rh(111) surface. Submonolayer deposits of titania grow on the surface of Rh in the form of two-dimensional islands until a coverage of nearly a monolayer is achieved, at which point some three-dimensional growth of the islands is observed. The titania islands exclude CO chemisorption on Rh sites covered by the titania. The Ti/sup 4 +/ ions in the overlayer are readily reduced to Ti/sup 3 +/. This process begins at the perimeter of the islands and extends inwards as reduction proceeds. Titania promotion of Rh enhances the rate of Co hydrogenation by up to a factor of three and increases the selectivity to C/sub 2+/ hydrocarbons. By contrast, the activity of Rh for the hydrogenolysis of ethane decreases monotonically with increasing titania promotion. 16 refs., 6 figs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6712644
• Report Number(s): LBL-25828; CONF-880912-17; ON: DE89002667
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKANES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
DEPOSITION
DESORPTION
ELEMENTS
ETHANE
EVAPORATION
HYDROCARBONS
HYDROGENATION
LAYERS
METALS
METHANATION
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PLATINUM METALS
RHODIUM
SURFACES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS