XRD and Raman identification of the zirconia modifications in copper/zirconia and palladium/zirconia catalysts prepared from amorphous precursors

Journal Article · Thu Aug 01 04:00:00 EDT 1991 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1002/chin.199142018· OSTI ID:5544947

Schild, C; Wokaun, A ^[1]; Koeppel, R A; Baiker, A ^[2]

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1. Univ. of Bayreuth (West Germany)
2. Swiss Federal Inst. of Tech., Zuerich (Switzerland)

Recently, highly active CO{sub 2} hydrogenation catalysts have been obtained from glassy metal alloy precursors, i.e., Cu{sub 70}Zr{sub 30} and Pd{sub 33}Zr{sub 67}. During in situ activation under CO{sub 2} hydrogenation conditions, the zirconium component of the alloy is oxidized. For Pd/zirconia, the support matrix is identified as stable, monoclinic ZrO{sub 2}. In copper/zirconia, on the other hand, a metastable zirconia modification is prevalent, corresponding to either tetragonal or cubic ZrO{sub 2}. As the XRD patterns of these metastable phases are quite similar, additional information is required to distinguish between the two modifications. Both infrared and Raman spectroscopy have been established as suitable techniques to differentiate between tetragonal and cubic zirconia, as the information from the vibrational spectra is complementary to the X-ray diffraction data. In addition to the identification of the zirconia modification, particular attention is drawn in the present report to the influence of copper in amorphous Cu/Zr-alloys on the crystallization behavior of the zirconia. For comparison, two copper/zirconia catalysts were prepared by co-precipitation, drying, and subsequent reduction in a hydrogen atmosphere. These catalysts, denoted as Cu 70 and Cu 50, contain 70 at.% copper and 50 at.% copper on zirconia, respectively. In addition, the catalyst Cu 50 was calcined at 970 K for 2 h and then rapidly quenched to room temperature. The zirconia reference samples were precipitated, dried, and calcined, or else investigated without calcination.

• OSTI ID: 5544947
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 130:2; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010408 -- Coal
Lignite
& Peat-- C1 Processes-- (1987-)
36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ALLOYS
AMORPHOUS STATE
CALCINATION
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COHERENT SCATTERING
COPPER
CRYSTAL STRUCTURE
CRYSTALLIZATION
DECOMPOSITION
DIFFRACTION
ELECTROMAGNETIC RADIATION
ELEMENTS
HYDROGENATION
INFRARED RADIATION
LASER SPECTROSCOPY
METALS
METHANATION
MORPHOLOGICAL CHANGES
OXIDES
OXYGEN COMPOUNDS
PALLADIUM
PHASE TRANSFORMATIONS
PLATINUM METALS
PYROLYSIS
RADIATIONS
RAMAN SPECTROSCOPY
SCATTERING
SPECTROSCOPY
SYNTHESIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X-RAY DIFFRACTION
ZIRCONIUM ALLOYS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES