Phase transitions of BaTi&lt;SUB&gt;0.9&lt;/SUB&gt;Rh&lt;SUB&gt;0.1&lt;/SUB&gt;O&lt;SUB&gt;3±&lt;/SUB&gt;&lt;I&gt;&lt;SUB&gt;δ&lt;/SUB&gt;&lt;/I&gt; perovskite-type oxides under reducing environments

Mondragón Rodríguez, G.C.; Gönüllü, Y.; Ferri, Davide; Eyssler, Arnim; Otal, Eugenio; Saruhan, B.

doi:10.1016/j.materresbull.2014.10.007

Phase transitions of BaTi_0.9Rh_0.1O_3±_δ perovskite-type oxides under reducing environments

Mondragón Rodríguez GC, Gönüllü Y, Ferri D, Eyssler A, Otal E & Saruhan B

Citation

Mondragón Rodríguez, G. C., Gönüllü, Y., Ferri, D., Eyssler, A., Otal, E., & Saruhan, B. (2015). Phase transitions of BaTi_0.9Rh_0.1O_3±_δ perovskite-type oxides under reducing environments. Materials Research Bulletin, 61, 130-135. https://doi.org/10.1016/j.materresbull.2014.10.007

Persistent URL https://www.dora.lib4ri.ch/empa/islandora/object/empa:6608

Perovskite-type oxides of composition BaTi_0.9Rh_0.1O_3±_δ were prepared following a new chemical route that avoids the formation of hydroxyl species and precipitation, and allows the homogeneous distribution of Rh in the final mixed metal oxide. The high dispersion of Rh and the formation of the solid solution between Rh and the BaTiO₃ perovskite is confirmed by means of X-ray diffraction (XRD) and extended X-ray absorption fine structure spectroscopy (EXAFS). The presence of Rh stabilized the hexagonal BaTi_0.9Rh_0.1O_3±_δ phase, which decomposes into barium orthotitanate (BaTi₂O₄) and metallic Rh° in reducing environment. This phase transition starts already at 700 °C and is only partially completed at 900 °C suggesting that part of the Rh present in the perovskite lattice might not be easily reduced by hydrogen. These aspects and further open questions are discussed.