Local structure and nanoscale homogeneity of CeO2-ZrO2: differences and similarities to parent oxides revealed by luminescence with temporal and spectral resolution
2014 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 2, 703-710 p.Article in journal (Refereed) Published
Although homogeneity at the atomic level of CeO2-ZrO2 with a Ce/Zr atomic ratio close to unity is considered to be one of the main causes for the increased total oxygen storage capacity (OSC), the characterization approaches of homogeneity remain a major challenge. We propose a simple, yet effective method, to assess both structural and compositional homogeneity of CeO2-ZrO2 by using Eu3+ luminescence measured with time and dual spectral resolution (emission and excitation). For Eu3+-CeO2-ZrO2 calcined at 750 degrees C, the X-ray diffraction, Raman and High-Resolution Transmission Electron Microscopy data converge to a single pseudo-cubic phase. However, the evolution of Eu3+-delayed luminescence from cubic ceria-like to tetragonal zirconia-like emission reveals the formation of CeO2- and ZrO2-rich nanodomains and provides evidence for early phase separation. For Eu3+-CeO2-ZrO2 calcined at 1000 degrees C, the emission of Eu3+ reveals both structural and compositional inhomogeneity. Our study identifies the differences between the local structure properties of CeO2 and ZrO2 parent oxides and CeO2-ZrO2 mixed oxide, also confirming the special chemical environment of the oxygen atoms in the mixed oxide as reported earlier by Extended X-ray Absorption Fine Structure investigations.
Place, publisher, year, edition, pages
2014. Vol. 16, no 2, 703-710 p.
Oxygen Storage Capacity, X-Ray-Absorption, Continuous Hydrothermal Synthesis, Mixed Oxides, Solid-Solutions, Ceria-Zirconia, Supercritical Water, Thermal-Stability, Crystal-Structure, Redox Properties
Chemical Sciences Physical Sciences
IdentifiersURN: urn:nbn:se:kth:diva-139264DOI: 10.1039/c3cp52893fISI: 000327888100038ScopusID: 2-s2.0-84890091790OAI: oai:DiVA.org:kth-139264DiVA: diva2:685375
QC 201401092014-01-092014-01-082014-01-09Bibliographically approved