Proton conductive behaviors of Ba(ZnxNb1−x)O3−δ−y(OH)2y studied by infrared spectroscopy

Proton-conductive behaviors of oxy-hydroxide perovskites Ba(ZnxNb1−x)O3−δ−y(OH)2y (BZN) were investigated by Fourier transform infrared spectroscopy (FT-IR) at 40–600 ​°C. The in-situ FT-IR analysis upon heating in flowing N2 gas revealed a broad IR peak at about 2500–3700 ​cm−1, attributed to O–H stretching vibration modes. The broadened IR peak was deconvoluted with four Gaussian components, and their relative intensities are dependent on temperature, indicating the presence of site preference of protons in the BZN crystal lattice. The proton site preference in BZN was discussed based on the comparison of spectral features between BZN and Ba(Zr0.9Y0.1)O2.95 as a reference.