Modification of the redox behaviour of CeO{sub 2} induced by structural doping with ZrO{sub 2}

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1996.0373· OSTI ID:486386

Fornasiero, P; Balducci, G; Di Monte, R ^[1]

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1. Universita di Trieste (Italy); and others

Reduction/oxidation behaviour of high surface area CeO{sub 2} and Ce{sub 0.5}Zr{sub 0.5}O{sub 2} mixed oxide is compared. It is shown that introduction of ZrO{sub 2} into the CeO{sub 2} framework with formation of a solid solution strongly modifies the reduction behaviour in comparison to that seen with CeO{sub 2} alone. Remarkably, upon repetitive reduction/oxidation processes, the temperature of the reduction of the solid solution decreases from 900 to 700 K. Conversely, in the aged CeO{sub 2} sample, almost no reduction occurs below 900 K. Textural characterisation shows that the redox process favours a large sintering of both the samples and, unexpectedly, induces formation of a new mesoporosity centered at about 20 nm. The expansion/contraction of the lattice parameter upon, respectively, reduction/oxidation, detected by X-ray diffraction, is suggested to be responsible for the textural modification. The suppression of the redox capacities of CeO{sub 2} at moderate temperature is associated with the decrease of the surface area. The sintering process induces a structural modification of Ce{sub 0.5} Zr{sub 0.5}O{sub 2} which promotes the reduction in the bulk, resulting in a high efficiency of the Ce{sup 4+} {r_equilibrium} Ce{sup 3+} redox cycle at moderate temperatures. 44 refs., 6 figs., 4 tabs.

• OSTI ID: 486386
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 164; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
40 CHEMISTRY
CERIUM OXIDES
CRYSTAL DOPING
OXIDATION
REDUCTION
SOLID SOLUTIONS
SURFACE AREA
X-RAY DIFFRACTION
ZIRCONIUM OXIDES