Ionic conduction in Ba_xCe_(0.8)Pr_(0.2)O_(3-α)
来源期刊：JOURNAL OF RARE EARTHS2009年第5期
论文作者：SUN Yufeng QIU Ligan WANG Maoyuan
Key words：Ba_xCe_(0.8)Pr_(0.2)O_(3-α); ionic conduction; gas concentration cell; AC impedance; nonstoichiometry; rare earths;
Abstract: Ba_xCe_(0.8)Pr_(0.2)O_(3-α)(X=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas concentration cell and AC impedance spectroscopy methods, the electrical conduction behavior of the materials was investigated in different gases at 500-900 ℃. The influence of non-stoichiometry in the materials with x≠1 on conduction properties was studied and compared with that in the material with x=1. The results indicated that Ba_(1.03)Ce_(0.8)Pr_(0.2)O_(3-α) was a pure protonic conductor, and Ba_(0.98)Ce_(0.8)Pr_(0.2)O_(3-α) was a mixed conductor of protons and electrons in wet hydrogen at 500-900 ℃. BaCe_(0.8)Pr_(0.2)O_(3-α) was a pure protonic conductor in 500-600 ℃, and a mixed conductor of protons and electrons above 600℃ in wet hydrogen. In 500-900℃, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed con-ductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing bar-ium content in the materials in wet hydrogen, dry air and wet air, respectively.
SUN Yufeng1，QIU Ligan1，WANG Maoyuan1
(1.School of Chemistry and Chemical Engineering, Yancheng Teachers University, Yancheng 224051, China)
Abstract:Ba_xCe_(0.8)Pr_(0.2)O_(3-α)(X=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas concentration cell and AC impedance spectroscopy methods, the electrical conduction behavior of the materials was investigated in different gases at 500-900 ℃. The influence of non-stoichiometry in the materials with x≠1 on conduction properties was studied and compared with that in the material with x=1. The results indicated that Ba_(1.03)Ce_(0.8)Pr_(0.2)O_(3-α) was a pure protonic conductor, and Ba_(0.98)Ce_(0.8)Pr_(0.2)O_(3-α) was a mixed conductor of protons and electrons in wet hydrogen at 500-900 ℃. BaCe_(0.8)Pr_(0.2)O_(3-α) was a pure protonic conductor in 500-600 ℃, and a mixed conductor of protons and electrons above 600℃ in wet hydrogen. In 500-900℃, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed con-ductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing bar-ium content in the materials in wet hydrogen, dry air and wet air, respectively.
Key words:Ba_xCe_(0.8)Pr_(0.2)O_(3-α); ionic conduction; gas concentration cell; AC impedance; nonstoichiometry; rare earths;
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