Effect of the preparation method on the thermal stability of silica-supported nickel oxide as studied by EXAFS and TPR techniques

Journal Article · Sun Nov 01 04:00:00 EST 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90017-C· OSTI ID:5602102

Clause, O ^[1]; Bonneviot, L; Che, M ^[2]

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1. Institut Francais du Petrole, Rueil-Malmaison (France)
2. Universite Pierre et Marie Curie, Paris (France)

EXAFS analysis and Temperature-Programmed Reduction experiments (TPR) have been carried out on calcined Ni/SiO[sub 2] materials prepared by incipient wetness impregnation at different pH values, ion exchange with ammonia and ethylenediamine solutions, and deposition-precipitation. The interaction of the Ni(II) ions with silica is shown to be dependent on the first steps of catalyst preparation, i.e., deposition, washing, and drying. Silicates with a layer structure are formed in samples prepared by deposition-precipitation and ion exchange from ammoniacal solutions. Silicate formation inhibits the NiO crystallization up to 500[degrees]C. The silicate decomposition is favored when the thermal treatment is performed under reduced pressure. The reducibility of the nickel oxide phase resulting from silicate decomposition is strongly hindered in comparison with that of unsupported nickel oxide. The silicate formation is avoided using a strong chelating ligand such as ethylenediamine during ion exchange. With ethylenediamine, isolated Ni(II) species stable to 500[degrees]C are obtained. 35 refs., 10 figs., 2 tabs.

• OSTI ID: 5602102
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 138:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CLEANING
CRYSTALLIZATION
DEPOSITION
DRYING
IMPREGNATION
ION EXCHANGE
LAYERS
NICKEL COMPOUNDS
NICKEL OXIDES
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHASE TRANSFORMATIONS
PRECIPITATION
REDUCTION
SEPARATION PROCESSES
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SPECTROSCOPY
STABILITY
SYNTHESIS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
WASHING
X-RAY SPECTROSCOPY