Influence of potassium salt addition on the catalytic properties of silica-supported nickel

Journal Article · Sat Feb 01 04:00:00 EST 1986 · J. Catal.; (United States)

DOI:https://doi.org/10.1016/0021-9517(86)90006-0· OSTI ID:5231177

Praliaud, H; Dalmon, J A; Mirodatos, C; Martin, G A

The influence of potassium nitrate addition to Ni/SiO/sub 2/ catalysts on the kinetic parameters of various reactions (ethane and propane hydrogenolysis, D/sub 2/-CH/sub 4/ exchange, benzene and CO hydrogenations) has been investigated. The changes in the catalytic pattern and in kinetic parameters are similar to those reported for other host metals such as Fe and Ru. On potassium addition, the true activation energies (deduced from the Temkin relation) of hydrogenolysis, exchange and CO hydrogenation over Ni increase; the Ni-H bond strength decreases, while the nickel-carbon monoxide bond is reinforced. Potassium cannot be considered as a poison, blocking selectively specific sites of the metallic surface, but rather as an electronic modifier, giving rise to an electron enrichment of the metallic phase, strengthening or weakening the Ni-adsorbate bonds. This hypothesis is also in agreement with the higher selectivity of Ni-K/SiO/sub 2/ catalysts for ethylenics in the CO + H/sub 2/ reaction and cyclohexene in benzene hydrogenation.

• Research Organization: Institut de Recherches sur la Catalyse, Villeurbanne (France)
• OSTI ID: 5231177
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 97:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ACTIVATION ENERGY
ALKALI METAL COMPOUNDS
ALKANES
AROMATICS
BENZENE
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYTIC EFFECTS
CATALYTIC REFORMING
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
DEUTERIUM
ELEMENTS
ENERGY
ETHANE
HYDROCARBONS
HYDROGEN ISOTOPES
HYDROGENATION
IRON
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LIGHT NUCLEI
METALS
METHANATION
METHANE
NICKEL
NITRATES
NITROGEN COMPOUNDS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
POTASSIUM COMPOUNDS
POTASSIUM NITRATES
PROMOTERS
PROPANE
REACTION KINETICS
REFORMER PROCESSES
RUTHENIUM
SILICON COMPOUNDS
SILICON OXIDES
STABLE ISOTOPES
TRANSITION ELEMENTS