Investigation of structural and catalytic properties of BaLa4Cu5−yRuyO13−δ with 0.0 ≤ y ≤ 3.0 and of LaBaCuRuO6

We have investigated the possibility of substituting Ru for Cu in the BaLa4Cu5O13−δ structure according the formula BaLa4Cu5−yRuyO13−δ with 0 ≤ y ≤ 3. In the BaLa4Cu5O13−δ structure the solubility of Ru was found to be limited to y < 0.5. For y ≥ 0.5, the samples contained a perovskite-related phase of the composition BaxLa4−xCu2.5Ru2.5O13−δ. A monophasic sample was obtained for x = 2.5, with the composition LaBaCuRuO6, confirmed by X-ray diffraction studies and elemental analysis of individual grains by scanning electron microscopy (SEM). Its structure was determined from X-ray powder diffraction (XRPD) data, using the Rietveld method, and found to be a double-perovskite type with the space group I4/mand the unit-cell parameters a = 5.6328(1) and c = 7.9877(1). The catalytic activity for simultaneous oxidation of CO and C3H6, and reduction of NO was studied over BaLa4Cu5O13−δ, BaLa4Cu4.75Ru0.25O13−δ, La4BaCu2.5Ru2.5O13−δ, and LaBaCuRuO6, under both reducing and oxidizing conditions. BaLa4Cu5O13−δ exhibited some catalytic activity for oxidation of CO and C3H6, whereas reduction of NO was found only for the Ru containing samples, and under reducing conditions. The best catalytic activity for oxidation of CO and C3H6 and reduction of NO was found for the perovskite-related sample La4BaCu2.5Ru2.5O13−δ.