Surface Crystalline Phase and Basicity of MgO/ZrO2-La2O3-y Solid Base Catalyst

Abstract

MgO/ZrO2-La2O3-y solid base catalyst was prepared by precipitation immersion process. Raman spectroscope and X-ray powder diffraction (XRD) were used to determinate the surface phase and bulk phase of solid base catalyst. Temperature programmed desorption of CO2 (CO2-TPD) was employed to study the surface basicity of the catalyst. The results reveal that Mg2+ ion plays a key role in the stabilization of tetragonal phase ZrO2 not only in the bulk but also on the surface of catalyst when the Mg/Zr molar ratio is 0.4. The doping of La2O3 has the role of improving the dispersion of the active component MgO on ZrO2 surface, consequently resulting in the improvement of the catalytic activity of the catalyst rather than stabilizing tetragonal phase ZrO2.