Studies of n-butane conversion over silica-supported platinum, platinum-silver and platinum-copper catalysts
The present work was undertaken to elucidate effect of adding silver and copper to silica-supported platinum catalyst on the activity and selectivity in the n-butane reactions. At the conditions of this study n-butane underwent both hydrogenolysis and structural isomerization. The catalytic activity and selectivities between hydrogenolysis and isomerization and within hydrogenolysis were measured at temperature varying from 330 C to 370 C. For platinum-silver catalysts, at lower temperatures studied the catalytic activity per surface platinum atom (turnover frequency) remained constant at lower silver content (between 0 at. % and 30 at. %) and decreased with further increased silver loading, suggesting that low- index planes could be dominant in the hydrogenolysis of n-butane. Moreover, increasing silver content resulted in an enhancement of the selectivity of isomerization products relative to hydrogenolysis products. At the higher temperature studied, no suppression in catalytic activity was observed. It is postulated that surface structure could change due to the mobility of surface silver atoms, leading to surface silver atoms forming islands or going to the bulk, and leaving large portions of basal planes exposed with active platinum atoms. It is also suggested that the presence of inert silver atoms results in weakening of the H-surface bond. This results in increased mobility of hydrogen atoms on the surface and hence, higher reactivity with other adsorbed species. For platinum copper catalysts, the mixed ensembles could play an active role in the hydrogenolysis of n-butane.
- Research Organization:
- Ames Lab., IA (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 5048314
- Report Number(s):
- IS-T-1594; ON: DE92016309
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360104* -- Metals & Alloys-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKANES
ALLOYS
BIMETALS
BUTANE
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
COPPER ALLOYS
HYDROCARBONS
ISOMERIZATION
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM ALLOYS
PLATINUM BASE ALLOYS
PLATINUM METAL ALLOYS
SEPARATION PROCESSES
SILICON COMPOUNDS
SILICON OXIDES
SILVER ALLOYS
SORPTION