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Ionic Conduction in Ba 0.95 Ce 0.8 Ho 0.2 O 3− α
Author(s) -
Wang MaoYuan,
Qiu LiGan,
Ma GuiLin
Publication year - 2007
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200790236
Subject(s) - chemistry , ionic conductivity , ionic bonding , orthorhombic crystal system , hydrogen , atmospheric temperature range , analytical chemistry (journal) , electrolyte , oxide , conductivity , inorganic chemistry , ion , electrode , crystallography , crystal structure , physics , organic chemistry , chromatography , meteorology
Ba 0.95 Ce 0.8 Ho 0.2 O 3− α was prepared by high temperature solid‐state reaction. X‐ray diffraction (XRD) pattern showed that the material was of a single perovskite‐type orthorhombic phase. Using the material as solid electrolyte and porous platinum as electrodes, the measurements of ionic transport number and conductivity of Ba 0.95 Ce 0.8 Ho 0.2 O 3− α were performed by gas concentration cell and ac impedance spectroscopy methods in the temperature range of 600–1000 °C in wet hydrogen, dry and wet air respectively. Ionic conduction of the material was investigated and compared with that of BaCe 0.8 Ho 0.2 O 3− α . The results indicated that Ba 0.95 Ce 0.8 Ho 0.2 O 3− α was a pure protonic conductor with the protonic transport number of 1 during 600–700 °C in wet hydrogen, a mixed conductor of protons and electrons with the protonic transport number of 0.97–0.93 in 800–1000 °C. But BaCe 0.8 Ho 0.2 O 3− α was almost a pure protonic conductor with the protonic transport number of 1 in 600–900 °C and 0.99 at 1000 °C in wet hydrogen. In dry air and in the temperature range of 600–1000 °C, they were both mixed conductors of oxide ions and electronic holes, and the oxide‐ionic transport numbers were 0.24–0.33 and 0.17–0.30 respectively. In wet air and in the temperature range of 600–1000 °C, they were both mixed conductors of protons, oxide ions and electronic holes, the protonic transport numbers were 0.11–0.00 and 0.09–0.01 respectively, and the oxide‐ionic transport numbers were 0.41–0.33 and 0.27–0.30 respectively. Protonic conductivity of Ba 0.95 Ce 0.8 Ho 0.2 O 3− α in both wet hydrogen and wet air was higher than that of BaCe 0.8 Ho 0.2 O 3− α in 600–800 °C, but lower in 900–1000 °C. Oxide‐ionic conductivity of the material was higher than that of BaCe 0.8 Ho 0.2 O 3− α in both dry air and wet air in 600–1000 °C.