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

• Identification of the role of dopant–oxygen bonding type on hydroxide formation.
• Stronger OH bonds in oxides with In3+ and Sc3+ dopants than with Y3+.
• Oxide structural properties independent on dopant chemical nature.

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 0.375) 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 OH 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 OH vibrations vary by 250–1500 cm− 1 depending on the acceptor-dopant.