ISSN:
1573-8663
Keywords:
proton conduction
;
perovskite
;
scandium oxide
;
concentration cell
;
electrochemical pump
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Ionic transport properties of perovskite-type oxides based on LnScO3, Ln1- xCaxScO3-α (Ln=La, Nd, Sm and Gd) and LaSc1-xMgxO3-α were studied using an electrochemical method at elevated temperatures. Conductivity in these oxide systems increased by more than three orders of magnitude upon doping with divalent atoms such as Ca or Mg. However, when x≥0.1, conductivities are almost independent of x in La1- xCaxScO_3-α and LaSc1- xMgxO3-α. Gd0.9Ca0.1ScO3-α showed lower conductivity than Ln1-xCaxScO3-α (Ln=La, Nd and Sm). Protonic conduction in these oxides under hydrogen containing atmospheres was confirmed by emf measurements of hydrogen concentration cells and by electrochemical hydrogen pumping using these oxides as a diaphragm. In LaSc1-xMgxO3-α the transport number of protons under hydrogen containing atmosphere was unity, suggesting that electronic conduction never became dominant, even under strong reducing conditions. Under condition of high oxygen partial pressure, the transport number of ions was less than 0.1, suggesting that the majority conductive carriers under such conditions were holes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009935208872
Permalink
