Effect of dopant nature on structures and lattice dynamics of proton-conducting BaZrO3

The influence of the acceptor-dopants on the local and long range structures and lattice vibrations of barium zirconate has been studied with Density Functional Theory (DFT) based periodic approach. Structural details of BaZr1-xMxHxO3 (M = In and Sc, and x = 0.125, 0.25 and 0375) with protonic defects in three different oxygen configurations are presented and discussed in relation with the results for Y-doped barium zirconates, obtained previously with the same methodology. The oxide symmetry and the short and long range structural arrangements in the M-rich and Zr-rich regions were established nearly independent on the dopant chemical nature, concentration and arrangement in the cell. The O-H bond formation is however strongly influenced by the dopant nature, which is associated with the differences in dopant-oxygen bond character. The computed lattice vibrations in zirconates with Y, In and Sc dopants showed that the O-H vibrations vary by 250-1500 cm(-1) depending on the acceptor-dopant. (C) 2013 Elsevier B.V. All rights reserved.