Reversibility of strong metal-support interactions on Rh/TiO sub 2

Journal Article · Sat Jul 01 04:00:00 EDT 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90313-8· OSTI ID:7015216

Braunschweig, E J; Logan, A D; Datye, A K ^[1]; Smith, D J ^[2]

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1. Univ. of New Mexico, Albuquerque (USA)
2. Arizona State Univ., Tempe (USA)

Hydrogenolysis of n-butane and CO hydrogenation were used to study the reversibility of the SMSI state in Rh supported on model nonporous TiO{sub 2} spheres. High-temperature reduction (HTR) caused a three-order-of-magnitude drop in hydrogenolysis activity and led to increased selectivity toward ethane. Oxidation at 573 K was sufficient to restore the hydrogenolysis activity in these catalysts. Variations in hydrogenolysis selectivity on Rh/TiO{sub 2} were similar to those on Rh/SiO{sub 2} subjected to comparable treatments. This suggests that site blocking by TiO{sub x} may be primarily responsible for the suppressed hydrogenolysis activity on Rh/TiO{sub 2}. CO hydrogenation activity, on the other hand, was only marginally affected by the onset of SMSI and either increased or decreased after HTR depending on the prior treatment of the catalyst. High-resolution transmission electron microscopy showed the presence of 2- to 4-{angstrom} amorphous overlayers on both the Rh and the support after high-temperature reduction. The thickness of these overlayers was nonuniform and oxidation followed by low-temperature reduction led to partial removal of the overlayers and a roughening of the Rh metal surfaces.

• OSTI ID: 7015216
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 118:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

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02 PETROLEUM
020400 -- Petroleum-- Processing
ALKANES
AMORPHOUS STATE
BUTANE
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
DEHYDROGENATION
DIMENSIONS
ELECTRON MICROSCOPY
ELEMENTS
ETHANE
HYDROCARBONS
LAYERS
METALS
METHANATION
METHANE
MICROSCOPY
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
REDUCTION
RUTHENIUM
SILICON COMPOUNDS
SILICON OXIDES
SURFACE PROPERTIES
SYNTHESIS
THICKNESS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY