Peculiarities of electrical transfer and isotopic effects H/D in the proton-conducting oxide BaZr0.9Y0.1O3 − δ

Abstract

Electrical conduction of the oxide BaZr0.9Y0.1O3 − δ is studied by electrochemical impedance spectroscopy as a function of temperature (300–600°C) and the oxygen partial pressure in gas phase saturated with H2O or D2O vapor. The full electrical conduction is separated into components, in particular, the bulk and grain boundary conduction. It is shown that at P O2> 1 Pa the BaZr0.9Y0.1O3 − δ conduction is contributed significantly by electron holes whose transference number in air atmosphere may be as high as 0.5–0.6. In reductive conditions, the electrical transfer involves proton (deuteron) charge carriers. Isotopic effect H/D in the conduction in the bulk and along the grain boundaries is determined. Isotopic effect H/D in the hole conduction is also revealed. It is shown that this effect comes out of different solubility of deuterons and protons in the oxide (the thermodynamic isotopic effect).