Active ceria-calcium oxide catalysts for dimethyl carbonate synthesis by conversion of CO2

Abstract

Carbon dioxide has generated great interest in recent years because of its potential usage as an alternative to traditional sources of carbon such as natural gas, petroleum and coal. In this paper, CO2 in combination with methanol was used for dimethyl carbonate (DMC) synthesis in presence of cerium-calcium mixed oxide catalysts. Catalysts with different Ce/Ca molar ratios were synthesized using surfactant templating method and characterized by powder X-ray diffraction (XRD), Raman spectroscopy, N2–sorption, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and temperature-programmed desorption (TPD) of CO2 and NH3. The direct conversion of CO2 was found to be highly dependent upon the acidity and basicity of catalysts. Brunauer-Emmett-Teller (BET) surface area of Ce3Ca1, Ce1Ca1 and Ce1Ca3 was found to be 102, 82, 109m2/g, respectively, and the average pore diameter was 9, 12 and 5nm, respectively. The Ce1Ca1 catalyst performed the best due to its combined acidic-basic properties. In addition, the catalyst was reused up to five cycles without significant loss of performance.