Synthesis, characterisation, catalytic activity and structural stability of LaCo1−yFeyO3±λ perovskite catalysts for combustion of ethanol and propane

LaCo1−yFeyO3 perovskite-type oxides with y=0.1y=0.1, 0.3, and 0.5 were prepared by the citrate method and characterized by X-ray diffraction (XRD), BET surface area measurement (SSA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and Mössbauer spectroscopy. With this preparation method, a good inclusion of the substituting cation in the B-site is reached, maintaining the rhombohedral crystalline structure, modifying the volume of the unit cell, and weakening the BO bond. This likely affects the capacity and the mechanism of oxygen supply or the redox behavior. At high iron content, Fe4+ could exist. Surface enrichment in lanthanum was observed on XPS. The singularity observed in the improvement of the catalytic activity for y=0.1y=0.1, in both propane and ethanol combustion, could be explained by the electronic complexity introduced by iron in the perovskite conductor characteristics.