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

Abstract

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.

Authors:
; ;  [1]
  1. Universita di Trieste (Italy); and others
Publication Date:
OSTI Identifier:
486386
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 164; Journal Issue: 1; Other Information: PBD: Nov 1996
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 33 ADVANCED PROPULSION SYSTEMS; CERIUM OXIDES; REDUCTION; OXIDATION; ZIRCONIUM OXIDES; CRYSTAL DOPING; SOLID SOLUTIONS; X-RAY DIFFRACTION; SURFACE AREA

Citation Formats

Fornasiero, P, Balducci, G, and Di Monte, R. Modification of the redox behaviour of CeO{sub 2} induced by structural doping with ZrO{sub 2}. United States: N. p., 1996. Web. doi:10.1006/jcat.1996.0373.
Fornasiero, P, Balducci, G, & Di Monte, R. Modification of the redox behaviour of CeO{sub 2} induced by structural doping with ZrO{sub 2}. United States. https://doi.org/10.1006/jcat.1996.0373
Fornasiero, P, Balducci, G, and Di Monte, R. 1996. "Modification of the redox behaviour of CeO{sub 2} induced by structural doping with ZrO{sub 2}". United States. https://doi.org/10.1006/jcat.1996.0373.
@article{osti_486386,
title = {Modification of the redox behaviour of CeO{sub 2} induced by structural doping with ZrO{sub 2}},
author = {Fornasiero, P and Balducci, G and Di Monte, R},
abstractNote = {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.},
doi = {10.1006/jcat.1996.0373},
url = {https://www.osti.gov/biblio/486386}, journal = {Journal of Catalysis},
number = 1,
volume = 164,
place = {United States},
year = {1996},
month = {11}
}