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Structure and phase stability of nanocrystalline Ce1−xLnxO2−x/2−δ (Ln = Yb, Lu) in oxidizing and reducing atmosphere

Matecka, Maytgorzata A. and Burkhardt, Ulrich and Kaczorowski, Dariusz and Schmidt, Marcus P. and Goran, Daniel and Kępinski, Leszek (2009) Structure and phase stability of nanocrystalline Ce1−xLnxO2−x/2−δ (Ln = Yb, Lu) in oxidizing and reducing atmosphere. Journal of Nanoparticle Research, 11 (8). pp. 2113-2124.

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Abstract

The structure and phase evolution of nanocrystalline Ce1− x Ln x O2− x/2−δ (Ln = Yb, Lu, x = 0 − 1) oxides upon heating in H2 was studied for the first time. Up to 950 °C the samples were single-phase, with structure changing smoothly with x from fluorite type (F) to bixbyite type (C). For the Lu-doped samples heated at 1100 °C in the air and H2, phase separation into coexisting F- and C-type structures was observed for ~0.40 < x < ~0.70 and ~0.25 < x < ~0.70, respectively. It was found also that addition of Lu3+ and Yb3+ strongly hinders the crystallite growth of ceria during heat treatment at 800 and 950 °C in both atmospheres. Valency of Ce and Yb in Ce0.1Lu0.9O1.55−δ and Ce0.95Yb0.05O1.975−δ samples heated at 1100 °C was studied by XANES and magnetic measurements. In the former Ce was dominated by Ce4+, with small contribution of Ce3+ after heating in H2. In the latter, Yb existed exclusively as 3+ in both O2 and H2.

Item Type:Article
Subjects:Material Science > Nanostructured materials
ID Code:8812
Deposited By:CSMNT
Deposited On:26 Aug 2010 08:44
Last Modified:26 Aug 2010 08:45

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