Influence of particle size on catalytic properties of alumina-supported rhodium catalysts

Journal Article · Fri Feb 01 00:00:00 EST 1980 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(80)90391-7· OSTI ID:6454971

Fuentes, S; Figueras, F

Alumina-supported catalysts containing 0.08-2.35 rhodium were prepared by ion exchange or impregnation and hydrogen-reduced at 400/sup 0/-830/sup 0/C. Their degree of dispersion varied from 7.5 to 100%. The dispersion was determined by electron microscopy, hydrogen and oxygen adsorption, and titration of adsorbed oxygen with hydrogen. The stoichiometry of hydrogen and oxygen adsorption on the rhodium was 1:1, and oxygen adsorption did not change with dispersion as it did on platinum and palladium. The turnover number for benzene hydrogenation on these catalysts decreased slightly with increasing dispersion, which indicated that small particles were less active for hydrogenation than larger particles. The turnover number for the hydrogenolysis of cyclopentane decreased by a factor of eight and the selectivity for methane formation went through a maximum with increasing dispersion of the rhodium. An analysis of the data and comparison with available studies of hydrogenolysis on other metals suggested that particle size effects depend on variations of activity of crystal planes, i.e., the availability of facetted rather than spherical; particles, and not on the properties of edge, corner, and face atoms.

• Research Organization: Inst. Rech. Catal., C.N.R.S., Villeurbanne
• OSTI ID: 6454971
• Journal Information: J. Catal.; (United States), Vol. 61:2
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BENZENE
HYDROGENATION
HYDROGEN
ADSORPTION
METHANE
SYNTHESIS
OXYGEN
RHODIUM
CATALYTIC EFFECTS
ALUMINIUM OXIDES
CATALYST SUPPORTS
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
CYCLOALKANES
DATA ANALYSIS
DISPERSIONS
ELECTRON MICROSCOPY
HIGH TEMPERATURE
IMPREGNATION
ION EXCHANGE
PALLADIUM
PARTICLE SIZE
PLATINUM
REDUCTION
SPECIFICITY
TITRATION
VERY HIGH TEMPERATURE
ALKANES
ALUMINIUM COMPOUNDS
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
HYDROCARBONS
METALS
MICROSCOPY
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
SIZE
SORPTION
TRANSITION ELEMENTS
090121* - Hydrocarbon Fuels- Chemical Synthesis- (1976-1989)
400201 - Chemical & Physicochemical Properties
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)