Reduction of Ni sup 2+ cations in Y zeolites. II. Effect of the environment

Journal Article · Wed Jul 01 00:00:00 EDT 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90116-Y· OSTI ID:7142141

Coughlan, B; Keane, M A ^[1]

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1. Univ. College, Galway (Ireland)

The reduction of Ni{sup 2+} cations supported on a range of both ion-exchanged and impregnated Y zeolites, enriched to various levels with Li{sup +}, Na{sup +}, K{sup +}, Rb{sup +}, Cs{sup +}, NH{sub 4}{sup +}, and Ce{sup 3+} cations, was investigated. The reduction process was found to be a dynamic equilibrium governed by the level of nickel exchange and the Broensted acidity associated with each zeolite sample. At lower levels of exchange (< 10 Ni{sup 2+}/UC), nickel reducibility is inversely related to the strength of coordination of the nickel ions to the zeolite lattice and increases in the order NiCsNaY < NiRbNaY < NiKY < NiNaY < NiLiY. At higher loadings, the percentage Ni{sup 2+} reduction decreases with increasing Broensted acidity in the sequence NiCsNaY > NiRbNaY > NiKY > NiNaY > NiLiY. The reduction of Ni{sup 2+} ions supported on NH{sub 4}Y was negligible. In the case of the CeNiNaY and CeNiKY samples, the introduction of an additional level of acidity, due to the presence of the strongly polarizing Ce{sup 3+} ions during thermal activation served to further suppress the reduction process resulting in values of Ni{sup 2+} reduction lower than those of the NiNaY and NiKY samples. The effect of poisoning the acid sites by the adsorption of a number of bases was considered. Comparative data on the reduction of Ni{sup 2+} ions supported on alumina and silica are also included.

• OSTI ID: 7142141
• Journal Information: Journal of Catalysis; (United States), Vol. 136:1; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
NICKEL COMPOUNDS
REDUCTION
ALUMINIUM OXIDES
AMMONIA
BROENSTED ACIDS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CATIONS
CERIUM
CESIUM
CHEMICAL ACTIVATION
COMPARATIVE EVALUATIONS
CONFIGURATION INTERACTION
ENRICHMENT
IMPREGNATION
ION EXCHANGE
LITHIUM
POTASSIUM
RUBIDIUM
SILICON OXIDES
SODIUM
SURFACE PROPERTIES
ZEOLITES
ALKALI METALS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
ELEMENTS
EVALUATION
HYDRIDES
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
MATERIALS
METALS
MINERALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXIDES
OXYGEN COMPOUNDS
RARE EARTHS
SILICATE MINERALS
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical &amp; Physicochemical Properties