Redispersion of sintered Pt, Rh, and Pt/Rh catalysts

Journal Article · Mon Feb 01 04:00:00 EST 1988 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(88)90223-0· OSTI ID:5354012

D'Aniello, Jr, M J; Monroe, D R; Carr, C J; Krueger, M H

Sintered Pt/alumina catalysts can be readily redispersed by treatment with chlorine, chlorine/air mixtures, or bromine at temperatures above 400/sup 0/C. The redispersion of Pt has been verified by hydrogen chemisorption, high resolution transmission electron microscopy, and catalytic activity measurements. Sintered Rh/alumina catalysts can be redispersed by a chlorine treatment at 500/sup 0/C, but only when this treatment is preceded by a hydrogen treatment at or above 700/sup 0/C. Sintered bimetallic Pt-Rh/alumina catalysts can be partially redispersed by direct treatment with chlorine at 500/sup 0/C and more completely redispersed if the chlorine treatment is preceded by a hydrogen treatment at 700/sup 0/C. However, unlike Pt/alumina, improvements in the catalytic activity of Rh/alumina or Pt-Rh/alumina do not necessarily accompany improvements in dispersion. For these catalysts, activity appears to be dominated by the recent oxidation or reduction history of the catalyst.

• Research Organization: General Motors Research Labs., Warren, MI (USA)
• OSTI ID: 5354012
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 109:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES
AIR
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BIMETALS
BROMINE
CATALYST SUPPORTS
CATALYSTS
CATALYTIC CONVERTERS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHEMISORPTION
CHLORINE
DISPERSIONS
DISTRIBUTION
ELECTRON MICROSCOPY
ELEMENTS
EQUIPMENT
FABRICATION
FLUIDS
GASES
HALOGENS
HYDROGEN
METALS
MICROSCOPY
MIXTURES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
POLLUTION CONTROL EQUIPMENT
REGENERATION
RHODIUM
SEPARATION PROCESSES
SINTERING
SORPTION
SURFACE PROPERTIES
SYNTHESIS
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY