Metal segregation in supported bimetallic catalysts:. gamma. -Al/sub 2/O/sub 3/-supported CO hydrogenation catalysts prepared from RhOs/sub 3/, Rh/sub 4/, and FeOs/sub 3/ clusters

Journal Article · Fri Feb 01 00:00:00 EST 1985 · J. Catal.; (United States)

OSTI ID:5325398

Budge, J R; Lucke, B F; Gates, B C; Toran, J

Al/sub 2/O/sub 3/-supported metals were prepared from (H/sub 2/RhOs/sub 3/(CO)/sub 10/(acetylacetonate)), (Rh/sub 4/(CO)/sub 12/), and (H/sub 2/FeOs/sub 3/(CO)/sub 13/). The samples were characterized by infrared spectroscopy after reaction with CO + H/sub 2/ and tested as catalysts for conversion of CO + H/sub 2/ in a flow reactor at 200 and 270/sup 0/C and 10 atm. Used catalysts were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, and elemental analysis. The catalyst lost Os during operation, presumably as a result of formation of volatile carbonyls. The catalytic reaction products were a nearly Schulz-Flory-Anderson distribution of hydrocarbons with small yields of dimethyl ether (formed from methanol). The performance of the catalyst prepared from the RhOs/sub 3/ clusters was closely similar to that of the catalyst prepared from the Rh/sub 4/ cluster. Characterization of the samples after treatment in CO + H/sub 2/ and after catalysis demonstrated that the RhOs/sub 3/ clusters broke apart, first giving triosmium clusters and mononuclear Rh complexes and then, at higher temperatures, giving Rh crystallites and mononuclear Os complexes. The catalytic activity for hydrocarbon synthesis is attributed to the Rh metal; the activity for methanol synthesis is tentatively associated with ionic Rh complexes. The FeOs/sub 3/ catalyst was two orders of magnitude less active than the Rh Os/sub 3/ catalyst, apparently consisting of small iron oxide particles and mononuclear Os complexes. The selectivity of this catalyst for dimethyl ether formation increased markedly with time onstream in the flow reactor; after 55 h, 36 mol% of the organic product was ether. 25 refs., 5 figs., 3 tabs.

• Research Organization: Univ. of Delaware, Newark; DuPont de Nemours and Co., Wilmington, DE
• OSTI ID: 5325398
• Journal Information: J. Catal.; (United States), Vol. 91:2
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
ALUMINIUM OXIDES
CATALYTIC EFFECTS
IRON
METHANATION
CATALYSTS
OSMIUM
RHODIUM
ABSORPTION SPECTROSCOPY
ACETYLACETONE
CARBON MONOXIDE
ETHERS
EXPERIMENTAL DATA
HYDROGEN
INFRARED SPECTRA
ALUMINIUM COMPOUNDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHELATING AGENTS
CHEMICAL REACTIONS
DATA
ELEMENTS
INFORMATION
KETONES
METALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
REAGENTS
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENTS
090121* - Hydrocarbon Fuels- Chemical Synthesis- (1976-1989)