n-Butane hydrogenolysis as a probe of surface sites in rhodium metal particles: Correlation with single crystals

Journal Article · Thu Feb 18 04:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100109a031· OSTI ID:6259330

Kalakkad, D; Anderson, S L; Datye, A K ^[1]; Logan, A D ^[2]; Pena, J ^[3]; Braunschweig, E J ^[4]; Peden, C H.F. ^[5]

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1. Univ. of New Mexico, Albuquerque (United States)
2. Univ. of New Mexico, Albuquerque (United States) Ford Motor Company, Dearborn, MI (United States)
3. Univ. of New Mexico, Albuquerque (United States) Dow Chemicals, Freeport, TX (United States)
4. Univ. of New Mexico, Albuquerque (United States) 3M, St. Paul, MN (United States)
5. Sandia National Labs., Albuquerque, NM (United States)

Rh metal was supported on alumina and silica supports and the particle size was varied (from <1 to >5 nm) by changing the metal loading from 0.03 to 7.2 [mu]mol of Rh/m[sup 2] of support. Metal particle sizes were determined by transmission electron microscopy. Hydrogenolysis of n-butane was used as a probe reaction. The effect of particle size and preoxidation on the hydrogenolysis activity and product selectivity was studied. The ethane selectivity of the highly dispersed Rh was very different from that of the low index single crystal surfaces of Rh. As particle size was increased, the selectivity of the catalysts approached that of Rh(111). Annealing the catalysts at 773 K in H[sub 2] led to better agreement between the supported Rh and single-crystal Rh(111). None of the catalysts after initial H[sub 2] reduction resembled the (100) or (110) surfaces in their hydrogenolysis selectivity. Since the (111) close packed surface would be favored during particle growth, it is understandable that these high temperature treatments lead to better agreement between the behavior of small particles and single crystals. 18 refs., 15 figs., 2 tabs.

• OSTI ID: 6259330
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:7; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals &amp; Alloys-- Preparation &amp; Fabrication
360104 -- Metals &amp; Alloys-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ALKANES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ANNEALING
BUTANE
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTALS
ELECTRON MICROSCOPY
ELEMENTS
HEAT TREATMENTS
HYDROCARBONS
METALS
MICROSCOPY
MINERALS
MONOCRYSTALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PLATINUM METALS
RHODIUM
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SIZE
SURFACE PROPERTIES
TRANSITION ELEMENTS