The water electrolysis operating at temperature below 700°C is recently considered as one of the most efficient and economical methods to obtain the hydrogen – future energetic carrier^1,2. Prior to the better industrial application it is crucial to well understand the modifications of the host perovskite behaviour induced by the protonic species³. Therefore, the high pressure Raman study of pure, Ln-modified protonated and non-protonated SrZrO₃ dense ceramics were performed between 0.1 and 40 GPa using a Diamond Anvil Cell (DAC). The comparison of the Raman spectra shows important differences in the pressure behaviour between the pure and Ln-modified SrZrO₃ ceramics. Simultaneously, rather similar sequence of phase transition (orthorhombic Pnma –10 GPa– > pseudo-tetragonal Imma –20 GPa– > tetragonal I4/mcm -35 GPa- > cubic Pm3m) was revealed in the case of Ln-modified samples, both protonated and non-protonated. Note that the lack of abrupt structural differences between protonated and non-protonated samples is very important from the application point of view because preserves the mechanical strength and the long life time. The main differences between the protonated and non-protonated ceramics concern the behaviour of Zr-O stretching mode of the Zr-O_6-x octahedron perturbated by neighbouring oxygen vacancies and Ln ions. The high pressure Raman results are compared with the Raman data as the function of high temperature as well as the diffraction and the thermal expansion ones.

1. S. Willemin, O. Lacroix, B. Sala, Ph. Colomban, A. Julbe, A. Ayral, H. Takenouti, J.P. Py, Desalination 200[1-3] (2006) 92.

2. PCT patent WO 2008/152317 A2 (18-12-2008).

3. A. Slodczyk, Ph. Colomban,  D. Lamago, MH. Limage, F. Romain, S. Willemin, B. Sala     Phase transitions in the H⁺ -conducting perovskite ceramics by the quasi-elastic neutron and high-pressure Raman scattering,  Ionics 14  (2008)  215.

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1. Proton diffusion in perovskites by Elastic and Quasi-Elastic Neutron Scattering measurement
2. Raman evaluation of the proton diffusion coefficient in the pressure protonated perovskite electrolytes
3. Raman intensity : an important tool in the study of nanomaterials and nanostructures