Structure, chemical stability and mixed proton-electron conductivity in BaZr_(0.9-x)-xPr_xGd_(0.1)O_(3-δ)

摘要

BaZr_(0.9-x)Pr_xGd_(0.1)O_(3-δ)(x = 0.3 and 0.6) was prepared by combustion synthesis and characterised with respect to conductivity and stability in an attempt to combine the desirable properties of the end members. The polycrystalline materials exhibit a cubic or pseudo-cubic structure as determined by X-ray synchrotron radiation and transmission electron microscopy. The chemical stability of the compositions is strongly dependent on the praseodymium content, the materials with more Pr present lower stability. Electron holes dominate the conductivity under oxidising atmospheres in BaZr_(0.3)Pr_(0.6)Gd_(0.1)O_(3-δ), while BaZr_(0.6)Pr_(0.3)Gd_(0.1)O_(3-δ) exhibits a mixed electron hole-proton conducting behaviour. Substitution of Zr by Pr in acceptor-doped BaZrCh decreases the sintering temperature and increases the grain growth rate.