Synthesis and characterization of ceria-supported catalysts for carbon dioxide transformation to diethyl carbonate

The support materials Al2O3, SiO2 and TiO2 were modified with 16 wt% CeO2, using two different preparation methods evaporation-impregnation and precipitation-deposition. The synthesized 16 wt% CeO2-Al2O3, 16 wt% CeO2-SiO2 and 16 wt% CeO2-TiO2 materials were characterized by means of X-ray powder diffraction for the phase purity, scanning electron microscopy for the morphology, nitrogen physisorption to determine the specific surface area and X-ray photo electron spectroscopy for the oxidation state of the Ce in the TiO2, Al2O3 and SiO2 matrices. Transmission electron microscopy was used to study the particle size of CeO2 whereas CO2-temperature programmed desorption (TPD) was used to determine the basicity of ceria-modified TiO2, Al2O3 and SiO2 catalysts. Furthermore, the catalytic performance of the as prepared CeO2-modified catalysts were compared in the synthesis of diethyl carbonate starting from ethanol and CO2 using butylene oxide as the dehydrating agent. The physico-chemical characterization results were correlated with the catalytic activity results and discussed in detail.