Microcalorimetric study of metal-support interaction in the Pt/TiO/sub 2/ system

Journal Article · Sun Mar 01 04:00:00 EST 1987 · J. Catal.; (United States)

OSTI ID:5468995

Herrmann, J M; Gravelle-Rumeau-Maillot, M; Gravelle, P C

Adsorption of hydrogen and carbon monoxide at the surface of anatase-supported platinum was studied by heat-flow calorimetry. When strong metal-support interaction (SMSI) is created by high-temperature (773 K) reduction of the sample in hydrogen, the metal area available for adsorption decreases to 10% of the total area initially present in the sample. However, the reactivity of the remaining metal surface, with respect to either carbon monoxide or hydrogen at 296 K, is similar to the reactivity of normal platinum. These results may be considered as indirect evidence for encapsulation (or decoration) of the metal by the reduced support. The small but significant decrease of the initial heat of adsorption of hydrogen following the development of SMSI indicates that the reduced support modifies the chemical properties of the surface metal atoms. Oxygen interacts at 296 K with the high-temperature pretreated Pt/TiO/sub 2/ sample and almost completely suppresses SMSI. The heat of regeneration is identical to the heat of reoxidation of titanium oxide (anatase), pretreated in the same conditions as the Pt/TiO/sub 2/ sample. It is close, in absolute value, to the heat of formation of anionic vacancies in the TiO/sub 2/ lattice, calculated from equilibrium measurements of electrical conductivity.

• Research Organization: Ecole Centrale, Lyon, France
• OSTI ID: 5468995
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 104:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010408* -- Coal
Lignite
& Peat-- C1 Processes-- (1987-)
ADSORPTION HEAT
CALORIMETRY
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
CHEMISORPTION
ELEMENTS
ENTHALPY
FORMATION HEAT
HYDROGEN
METALS
NONMETALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLATINUM
PLATINUM METALS
REACTION HEAT
REDUCTION
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS