Mesoporous CaO–ZrO 2 nano-oxides: A novel solid base with high activity and stability

Abstract

A new solid base, mesoporous CaO–ZrO 2 nano-oxides, was prepared via appropriate sol–gel process. It was found that such solid base showed high basicity and stability. Temperature programmed desorption of CO 2 confirmed that both weak and strong basic sites coexisted on the surface of CaO–ZrO 2 and the basicity could be modified by adjusting Ca/Zr molar ratio of the nano-oxides. The mesoporous CaO–ZrO 2 nano-oxides showed high thermal stability, since X-ray diffraction (XRD) and transmission electron microscopies (TEM) proved that the mesoporous network of this material preserved well even up to 700 °C. At the same time, XRD and Raman spectra indicated that Ca 2+ incorporated into t-ZrO 2 lattice and the basic sites were firmly anchored to the substrate. As a result, this novel solid base showed remarkable activity and durability in the synthesis of dimethyl carbonate from methanol and propylene carbonate.