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Substitution and proton doping effect on SrZrO3 behaviour: high-pressure Raman study



The high-pressure Raman studies of pure, Yb-modified, protonated and non-protonated SrZrO3 dense ceramics were performed between 0.1 and 40 GPa using a diamond anvil cell. Lanthanide-modified, protonated SrZrO3 perovskites are potential materials for electrolytic membrane in fuel cells and electrolysers working at medium temperature. The comparison of the Raman spectra shows important differences in the pressure behaviour between the pure and Yb-modified SrZrO3 ceramics. SrZrO3 exhibits a rigid structure without any structural modification, whereas for both SrZr0.93 Yb0.07 O2.965 and SrZr0.93 Yb0.07 O2.962 H0.003 a sequence of structural modifications at 10, 20 and 35 GPa is revealed. The character of these structural modifications is very similar to that observed as a function of the temperature (orthorhombic Pnma 750 °C → pseudo-tetragonal Imma 840 °C → tetragonal I4/mcm 1070 °C → cubic Pm3m), which suggests that they can be considered as the phase transitions. Despite the low level of proton content (0.3% mole/mole), significant difference between protonated and non-protonated compounds is observed for the 700–750 cm−1 doublet assigned to the Zr[BOND]O octahedron stretching mode, perturbed by an oxygen atom vacancy and/or neighbouring Yb ion. The location of proton is discussed. Copyright © 2011 John Wiley & Sons, Ltd.