Site selectivity of dopants in BaZr1-yMyO3-δ (M = Sc, Y, Sm, Eu, Dy) and measurement of their water contents and conductivities

The site selectivity of Sc, Y, Sm, Eu, and Dy in doped BaZrO3 was investigated. The measurement of water contents and conductivities of the samples were performed. The results revealed that for doping rare-earth cations into BaZrO3, all the examined dopants mainly occupied B-site, while a partial A-site occupation of Sm and Eu was significantly recognized. Sm and Eu are considered to be more amphoteric for doping into BaZrO3. The concentration of hydroxide ions in the sample of BaZr0.8Dy0.2O3-δ hydrated in wet Ar was obviously higher than that hydrated in wet O2 at the same humidification level. The bulk conductivity of BaZr0.8Dy0.2O3-δ in wet Ar or H2 is higher than that in a dry one, indicating the generation of protonic conductivity of BaZr0.8Dy0.2O3-δ. The strong dependence of conductivity on partial pressure of oxygen was also recognized. The bulk conductivities of BaZr0.8Dy0.2O3-δ in wet Ar and H2 were comparable to that of BaZr0.8Y0.2O3-δ.