Single-Phase PrOy−ZrO2 Materials and Their Oxygen Storage Capacity: A Comparison with Single-Phase CeO2−ZrO2, PrOy−CeO2, and PrOy−CeO2−ZrO2 Materials

Autor:	L. P. Haack, G. W. Graham, W. Chun, Chaitanya K. Narula, Hungwen Jen
Rok vydání:	1999
Předmět:	Materials science Praseodymium Analytical chemistry Mineralogy chemistry.chemical_element Thermal treatment Fluorite Surfaces Coatings and Films Catalysis Lattice constant chemistry Materials Chemistry Mixed oxide Physical and Theoretical Chemistry Ternary operation Powder diffraction
Zdroj:	The Journal of Physical Chemistry B. 103:3634-3639
ISSN:	1520-5207 1520-6106
DOI:	10.1021/jp984383n
Popis:	High-surface-area PrOy−ZrO2 mixed oxide, crystallized in the cubic fluorite structure, is synthesized for the first time as a single-phase material over a wide range of composition by sol−gel processing. X-ray powder diffraction shows that the material remains single phase even after thermal treatment in air to 900 °C. The oxygen storage capacity of PrOy−ZrO2, where praseodymium undergoes Pr3+ ↔ Pr4+ interconversion, is assessed by temperature-programmed reduction with H2. The results show that there is little oxygen storage capacity unless the PrOy concentration exceeds 25 mol %. A comparison of oxygen storage capacity from similarly prepared single-phase CeO2−ZrO2, PrOy−CeO2, and PrOy−CeO2−ZrO2 materials is presented. Measurements of lattice parameter and reducibility suggest that there are preferred associations that lead to PrOy−ZrO2 and CeO2−ZrO2 rather than PrOy−CeO2 in the ternary mixed oxide. An evaluation of model Pd catalysts, using PrOy−ZrO2 and CeO2−ZrO2 as support materials, in functional tes...
Databáze:	OpenAIRE
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