Ionic conduction in Ba_xCe_(0.8)Pr_(0.2)O_(3–α)  

作　　者：王茂元 仇立干 孙玉凤 

机构地区：[1]School of Chemistry and Chemical Engineering,Yancheng Teachers University

出　　处：《Journal of Rare Earths》2009年第5期819-824,共6页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (20771079);Qing Lan Project and the Natural Science Foundation of Education Department of Jiangsu Province (07KJB150126 and 08KJD150008)

摘　　要：BaxCe0.8Pr0.2O3-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 °C. 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 Ba1.03Ce0.8Pr0.2O3-α was a pure protonic conductor, and Ba0.98Ce0.8Pr0.2O3-α was a mixed conductor of protons and electrons in wet hydrogen at 500-900 °C. BaCe0.8Pr0.2O3-α was a pure protonic conductor in 500-600 °C, and a mixed conductor of protons and electrons above 600 °C in wet hydrogen. In 500-900 °C, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed conductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing barium content in the materials in wet hydrogen, dry air and wet air, respectively.BaxCe0.8Pr0.2O3-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 °C. 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 Ba1.03Ce0.8Pr0.2O3-α was a pure protonic conductor, and Ba0.98Ce0.8Pr0.2O3-α was a mixed conductor of protons and electrons in wet hydrogen at 500-900 °C. BaCe0.8Pr0.2O3-α was a pure protonic conductor in 500-600 °C, and a mixed conductor of protons and electrons above 600 °C in wet hydrogen. In 500-900 °C, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed conductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing barium content in the materials in wet hydrogen, dry air and wet air, respectively.

关 键 词：BaxCe0.8Pr0.2O3-α ionic conduction gas concentration cell AC impedance NONSTOICHIOMETRY rare earths 

分 类 号：O614.233[理学—无机化学]