Structural dependence of the selectivity of formic acid decomposition on faceted TiO sub 2 (001) surfaces
- Univ. of Delaware, Newark (USA)
The reactions of formic acid on TiO{sub 2} (001) single-crystal surfaces were examined by temperature-programmed desorption and x-ray photoelectron spectroscopy. The (011)-faceted and (114)-faceted surfaces were chosen as model surfaces in order to investigate the effects of surface structure and composition upon reaction selectivity and to identify the active sites. Formic acid adsorbed dissociatively at 300 K to yield surface formate species. Approximately 15% of the adsorbed formates was removed from the surface as formic acid at 390 K via recombination with surface hydroxyls. The remaining formates decomposed above 550 K to CO, CO{sub 2}, and formaldehyde, with selectivities toward these products dependent upon the surface structure and composition. On the (011)-faceted surface, which exposes fivefold oxygen-coordinated Ti{sup 4+} cations, adsorbed formates decomposed exclusively via unimolecular reactions to product CO and CO{sub 2}. On the (114)-faceted surface, which exposes four-, five-, and sixfold coordinated cations, the reaction of adsorbed formates to produce formaldehyde was also observed.
- OSTI ID:
- 6286862
- Journal Information:
- Langmuir; (USA), Journal Name: Langmuir; (USA) Vol. 6:9; ISSN 0743-7463; ISSN LANGD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
CARBOXYLIC ACIDS
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ELECTRON SPECTROSCOPY
EXPERIMENTAL DATA
FORMIC ACID
INFORMATION
MEASURING METHODS
MEDIUM TEMPERATURE
MONOCARBOXYLIC ACIDS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
SPECTROSCOPY
SURFACE PROPERTIES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS