Pt/Al/sub 2/O/sub 3/--1. Percentage exposed and its effect upon the reactivity of adsorbed oxygen

Journal Article · Tue Jul 01 04:00:00 EDT 1980 · J. Catal.; (United States)

OSTI ID:6321085

Kobayashi, K; Inoue, Y; Takahashi, N; Burewell, R L; Butt, J B; Cohen, J B

Catalysts containing approx. 0.3% platinum on alumina were prepared by impregnating the alumina with Pt(NH/sub 3/)/sub 2/(NO/sub 2/)/sub 2/ or Pt(NH/sub 3/)/sub 4/(NO/sub 3/)/sub 2/, drying in oxygen or air at < 400/sup 0/C and reducing at < 500/sup 0/C in hydrogen. The percentage of platinum exposed as measured by hydrogen chemisorption (Dh) was 4-100%, depending on the extent the catalyst was dried prior to reduction. Dh was equal to the exposed platinum determined by hydrogen-oxygen titration (Dt) for Dh < 45%, but at higher Dh, the Dt/Dh ratio decreased progressively. The ratio of adsorbed oxygen atoms to surface platinum atoms increased with increasing adsorption temperature and the O/Pt ratio was higher than 1:1 at sufficiently high temperatures. At the higher O/Pt ratios, not all oxygen reacted with hydrogen at 25/sup 0/C. The O/Pt ratio at which the reaction with hydrogen at 25/sup 0/C became incomplete was structure-sensitive and decreased from 1.15:1 for Dh = 36% to 0.5:1 for Dh = 94%.

• Research Organization: Northwestern Univ.
• OSTI ID: 6321085
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 64:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHEMICAL REACTORS
CHEMISORPTION
CONCENTRATION RATIO
ELEMENTS
HYDROGEN
METALS
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES
SYNTHESIS
TEMPERATURE EFFECTS
TRANSITION ELEMENTS