Synthesis, crystal structure and catalytic activity for C3H6 combustion of La–Sr–Cu–O–S with K2NiF4-type perovskite structure

K2NiF4 perovskite-type oxide catalysts containing sulfur, La2−xSrxCuO4Sy (0⩽x⩽0.30⩽x⩽0.3; 0⩽y⩽0.30⩽y⩽0.3), were synthesized to study their crystal structure, reduction–oxidation property, and catalytic activity for the combustion of C3H6 in the presence of SO2. Results of XRD, Rietveld analysis, TG, and XPS demonstrated that sulfur is located in the interstitial site between perovskite slabs as nonsulfate species (S4+/S6+). Because of the high positive valence of sulfur in the lattice, resulting charge compensation decreased the oxidation number of Cu from 2.08 (y=0y=0) to 1.86 (y=0.2y=0.2), accompanied by the creation of more reducible Cu species in TPR profiles, which would achieve the light-off of catalytic C3H6 combustion at lower temperatures. Admission of SO2 into the feedstream caused either a negative or a positive effect on the catalytic C3H6 oxidation, depending on the concentrations of SO2 and O2. More significantly, however, activation in the presence of SO2 was observed for sulfur-containing compound (y=0.2y=0.2), which suppressed the accumulation of adsorbed SO2 as sulfate (SO42−). It is proposed that the adsorption of SO2 leads to either positive or negative effects on catalytic activity depending on the oxidation state. The sulfur-containing compounds on exposure to SO2 would create the surface active site effective for the adsorption and combustion of C3H6.