Mesoporous CaO–ZrO2 nano-oxides: A novel solid base with high activity and stability

A new solid base, mesoporous CaO–ZrO2 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 CO2 confirmed that both weak and strong basic sites coexisted on the surface of CaO–ZrO2 and the basicity could be modified by adjusting Ca/Zr molar ratio of the nano-oxides. The mesoporous CaO–ZrO2 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 Ca2+ incorporated into t-ZrO2 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.