Surface and bulk modifications of 1.5 mole % Sr/La2O3 catalyst with different Co, Ni, and Cu amounts

The effects of Co, Ni and Cu oxide content on the surface and bulk of the 1 .5 mole % Sr/La2O3 catalysts were studied. Series of M/Sr-La catalysts (M = Co, Ni, Cu) were prepared by successive immersion impregnation. The solids were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR ), temperature-programmed reduction (TPR), electron paramagnetic resonance (EPR), specific surface area measurements (BET) and thermogravimetric analy sis (TGA). The Sr/La2O3 modified with different Co, Ni, and Cu loading show s a strong metal oxide interaction with La2O3. This probably begins over an ionic vacancies or structure defects favoring LaSrMOx solid solution format ion with island-like structures according to a Volmer-Weber growth. It is p roposed that the growth mode of La-Co, La-Ni and La-Cu stoichiometric phase s occur from solid solutions. The formation of only a La-M single phase, pr obably non-stoichiometric, increases the material porosity while different phases favor the agglomeration or sintering of the particles.