Cluster catalysis. Propane hydrogenolysis catalyzed by MgO-supported tetrairidium
- Univ. of Delaware, Newark, DE (United States) Univ. of California, Davis, CA (United States)
A metal carbonyl cluster with a tetrahedral metal frame, [HIr[sub 4](CO)[sub 11]][sup [minus]], was prepared on the surface of partially hydroxylated MgO powder by adsorption of [Ir[sub 4](CO)[sub 12]]. A supported catalyst was prepared by decarbonylation of the supported [HIr[sub 4](CO)[sub 11]][sup [minus]] by treatment in He followed by H[sub 2] at 300[degree]C. The surface structures were characterized by infrared and X-ray absorption spectroscopies. The decarbonylated cluster had an average Ir-Ir coordination number of 3.4, consistent with the hypothesis that the tetrahedral metal frame was largely retained after decarbonylation. The sample incorporating the decarbonylated clusters was catalytically active for propane hydrogenolysis at 1 atm and 200[degree]C. The catalyst that had been used for 1 day in a flow reactor was characterized by an Ir-Ir coordination number of 3.3. The lack of any significant change in the average cluster size indicates the stability of the supported catalyst, which is modeled as tetrahedral Ir[sub 4] clusters. The rate of the propane hydrogenolysis at 200[degree]C and atmospheric pressure with a H[sub 2]/propane molar ratio of 2.5 was 0.02 molecule of CH[sub 4] produced/(Ir[sub 4] cluster s). 70 refs., 9 figs., 3 tabs.
- OSTI ID:
- 6879405
- Journal Information:
- Journal of Physical Chemistry; (United States), Vol. 98:49; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
IRIDIUM COMPLEXES
SURFACE PROPERTIES
PROPANE
HYDROGENATION
ABSORPTION SPECTRA
ADSORPTION
CARBONYLS
CATALYSIS
CATALYST SUPPORTS
CHEMICAL REACTIONS
COMPILED DATA
HELIUM
INFRARED SPECTRA
MAGNESIUM OXIDES
METHANE
SOLID CLUSTERS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY SPECTROSCOPY
ALKALINE EARTH METAL COMPOUNDS
ALKANES
CHALCOGENIDES
COMPLEXES
DATA
ELECTRON MICROSCOPY
ELEMENTS
FLUIDS
GASES
HYDROCARBONS
INFORMATION
MAGNESIUM COMPOUNDS
MICROSCOPY
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RARE GASES
SORPTION
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties