Über gemischtvalente Ruthenium-Perowskite Ba3B3+Ru24,5+O9 – zur katalytischen Aktivität von Sauerstoffperowskiten mit vier- und fünfwertigen Edelmetallen

On Mixed Valent Perovskites Ba₃B³⁺Ru₂^4,5+O₉ – Catalytic Activity of Perovskite Oxides with Noble Metals The black compounds Ba₃B³⁺Ru₂O₉ crystallize with B³⁺ = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Y in a hexagonal BaTiO₃ structure (6 L, sequence (hcc)₂) with an ordered distribution (1:2 order) of B³⁺ and ruthenium (BO₆ single octahedra; Ru₂O₉ double groups). The mean oxidation state of ruthenium is about +4.5. The properties are compared with that of other isotypic stacking polytypes Ba₃B³⁺M₂^4,5O₉ (M₂ = IrRu, Ir₂, PtRu) and Ba₃B²⁺M₂⁵⁺O₉ (M = Ru, Ir). The results of activity tests concerning the efficiency of perovskite oxides with noble metals in respect of the oxidation of CO or CH_x and the reduction of NO_x are reported.