X-ray absorption fine structure analysis of local structure of CeO2–ZrO2 mixed oxides with the same composition ratio (Ce/Zr=1)

Synthesis of CeO2–ZrO2 solid solution by glycothermal method and its oxygen release capacity

“…The hydrogen consumption per mole Ce, however, was an order of magnitude smaller than that at the low-temperature peak(s). Since low-temperature reducibility is required for practical application, OSC of CeO 2 -ZrO 2 solid solution, in a general sense, is associated with the low-temperature peak [6]. The CP samples exhibited the same trend, although H 2 consumption was slightly smaller.…”

“…The distorted environment around Ce and Zr ions derived from the ordered (homogeneous) solid solution is assumed to be the cause for the favorable low-temperature reduction properties [6,50]. The CeO 2 -ZrO 2 samples synthesized by the GT process have highly homogeneous structure as compared with CeO 2 -ZrO 2 prepared by CP method, thus exhibiting favorable oxygen transfer properties.…”

“…It has been reported that the oxygen storage capacity (OSC) is generated by interconversion between Ce 4+ and Ce 3+ under oxidative and reductive conditions [5,6]. The OSC of the CeO 2 -ZrO 2 solid solution depends largely on the method of preparation; many physical properties such as crystallinity, crystallite and particle sizes, and homogeneity change depending upon its preparation methods and, thus, influence the OSC [7], and many methods such as solid-state reaction [8], high-energy milling [9], coprecipitation method [10,11], sol-gel method [12,13], citrate complex method [14], polymerized complex method [15], combustion synthesis [16,17], and hydrothermal method [18,19] have been reported.…”

X-ray Absorption Spectroscopic Characterization of Solid Acid-base Catalysts

“…A typical example of this discrepancy can be seen in the analysis of the Ce site in CeO2 _ ZrO2 automobile co-catalyst. Figure 15 shows Fourier transform k 3 -weighted Ce K-and L3-edge EXAFS (RSFs) of Ce0.5Zr0.5O2 automobile co-catalyst 64) . A distinct peak is observed around 3-4 Å in the RSF of the Ce K-edge, but was absent for the Ce L3-edge EXAFS.…”

“…A distinct peak is observed around 3-4 Å in the RSF of the Ce K-edge, but was absent for the Ce L3-edge EXAFS. Ce K-edge EXAFS and XRD characterizations have revealed that the Ce0.5Zr0.5O2 sample forms a highly crystallized solid solution homogeneously dispersed at the atomic level 64) ; but the corresponding Ce L3-edge EXAFS characterization might incorrectly suggest that Ce-species are present in a highly dispersed form or the sample was X-ray amorphous. Absence of the second coordination sphere at the Ce L3 edge was caused by interference to the EXAFS signals.…”