Fabrication and characterization of La-added MgFe2O4 as catalyst support for CO oxidation

Fe-containing oxides can serve as excellent supports for precious metal catalysts. Therefore, we investigated the catalytic properties of noble metals supported on Fe-containing mixed oxides. MgFe2O4 and La-added MgFe2O4 (La-MgFe2O4) were prepared via complexation with malic acid and characterized by X-ray diffraction, N-2 adsorption-desorption, and Fe K-edge X-ray fine structure analysis. MgFe2O4 calcined at 400-800 degrees C has a spinel structure and is porous. The addition of La to MgFe2O4 increased the local structural disorder around Fe, suppressed grain growth, affected the pore size, and increased the specific surface area. In addition, a Pd-loaded La-MgFe2O4 catalyst was prepared and found to exhibit higher activity for CO oxidation than a representative Pd/gamma-Al2O3 catalyst. Further, temperature-programmed reduction studies revealed that the reactivity of the surface lattice oxygen of La-MgFe2O4 was enhanced by the Pd loading. Further, diffuse reflectance Fourier transform infrared spectroscopy studies showed that the surface lattice oxygen reacted with CO to form CO2.