Valence characteristics and structural stabilities of the electrolyte solid solutions Ce1-xRExO2-delta (RE = Eu, Tb) by high temperature and high pressure

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	Valence characteristics and structural stabilities of the electrolyte solid solutions Ce1-xRExO2-delta (RE = Eu, Tb) by high temperature and high pressure
	L. P. Li; G. S. Li; Y. L. Che; W. H. Su
	2000
发表期刊	Chemistry of Materials
ISSN	0897-4756
卷号	12 期号:9 页码:2567-2574
摘要	Solid solutions Ce1-xRExO2-delta (RE = Eu, Tb) were prepared by a high-temperature and -pressure method. The products were characterized by X-ray diffraction (XRD), TG, electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and Mossbauer spectroscopy. XRD data analysis showed that all solid solutions crystallized in a single-phase cubic fluorite structure. The nonlinear relationships between the lattice parameter and dopant content for both series of solutions were ascribed to the results of cation substitutions and variations of the relative content of oxygen vacancy Vo and defect associations {RE'(Ce)Vo} and {Ce'(Ce)Vo}. EPR and XPS measurements confirmed the presence of Ce3+ ions in the solid solutions. For the solid solutions Ce1-xEuxO2-delta, all Eu ions were determined to be trivalent by XPS and Eu-151 Mossbauer measurements. For the solutions Ce1-xTbxO2-delta, all Tb ions were also stabilized in the trivalent state. This result is different from that of the counterpart by hydrothermal conditions, in which a mixed valence of Tb3+/Tb4+ prevails at a higher dopant content. The prepared solutions Ce1-xTbxO2-delta were metastable. With increasing temperature, they would be destabilized and decompose into two fluorite phases, accompanied by partial oxidation from Tb3+ to Tb4+. Alternating current impedance spectroscopy showed primarily bulk conduction for all samples. For the solutions Ce1-xEuxO2-delta, the temperature dependence of the ionic conductivity was linear within the temperature range measured with activation energies of 1.05, 0.82, and 0.87 for x = 0.2, 0.38, and 0.5, respectively. For the decomposition product of the solid solution Ce0.71Tb0.29O2-delta, the conductivity gave two linear regions with smaller activation energies; i.e., the activation energy was 0.60 eV below 600 degrees C and 0.39 eV above 600 degrees C. The higher ionic conductivity (1.1 x 10(-2) S/cm at 720 degrees C) for the decomposition phases of the solution Ce0.71Tb0.29O2-delta was ascribed to an electronic component involved in; relation to the presence of the mixed valence of Tb3+/Tb4+ and Ce3+/Ce4+.
部门归属	tohoku univ, dept chem engn, res ctr supercrit fluid technol, sendai, miyagi 9808579, japan. jilin univ, dept phys, changchun 130023, peoples r china. jilin univ, key lab inorgan synth & preparat chem, changchun 130023, peoples r china. acad sinica, int ctr mat phys, shenyang 110015, peoples r china.;li, gs (reprint author), tohoku univ, dept chem engn, res ctr supercrit fluid technol, sendai, miyagi 9808579, japan
关键词	Hydrothermal Synthesis Spectroscopy Glasses Xps
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WOS记录号	WOS:000089458000012
引用统计	被引频次：67[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/37089
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	L. P. Li,G. S. Li,Y. L. Che,et al. Valence characteristics and structural stabilities of the electrolyte solid solutions Ce1-xRExO2-delta (RE = Eu, Tb) by high temperature and high pressure[J]. Chemistry of Materials,2000,12(9):2567-2574.
APA	L. P. Li,G. S. Li,Y. L. Che,&W. H. Su.(2000).Valence characteristics and structural stabilities of the electrolyte solid solutions Ce1-xRExO2-delta (RE = Eu, Tb) by high temperature and high pressure.Chemistry of Materials,12(9),2567-2574.
MLA	L. P. Li,et al."Valence characteristics and structural stabilities of the electrolyte solid solutions Ce1-xRExO2-delta (RE = Eu, Tb) by high temperature and high pressure".Chemistry of Materials 12.9(2000):2567-2574.