Influence of the simultaneous substitution of Cu and Ru in the perovskite-type (La,Sr)MO3 (MAl, Mn, Fe, Co) on the catalytic activity for CO oxidation and CO–NO reactions Original Research Article

Catalytic activities of perovskite-type La0.8Sr0.2M1−2yIIICuyRuyO3 (MIII = Al, Mn, Fe, Co) for CO oxidation and CO–NO reactions were changed significantly by simultaneous Cu/Ru substitution, depending on the host MIII cations. Cu/Ru substitution caused the decrease of both activities (Co) and the preferential promotion of activity for CO oxidation (Fe) or the CO–NO (Mn) reaction. When the Cu/Ru pair was substituted in inert La0.8Sr0.2AlO3, the catalytic activities for both reactions increased remarkably, and the resulting La0.8Sr0.2Al0.8Cu0.1Ru0.1O3 showed activity comparable to Pt/Al2O3 and La0.8Sr0.2CoO3. It is inferred that Cu and Ru ions in the Al-based perovskite promote, respectively, the reduction step of the catalyst by CO and the oxidation step of this reduced catalyst by NO.