Low-temperature fabrication of K2O supported mesoporous tetragonal ZrO2 solid base for synthesis of dimethyl carbonate

In the present work, a new strategy was developed to fabricate strong basicity on mesoporous zirconia by in-situ preservation of carbon species originated from organic template during the thermal treatment of mesoporous ZrO2. The carbon species was maintained on mesoporous zirconia by calcination in N-2 prior to the introduction of base precursor KNO3. The decomposition temperature of KNO3 to strongly basic site K2O was significantly reduced from higher than 650 degrees C to about 400 degrees C in the presence of carbon species, which fascinatingly converted the endothermic decomposition reaction to exothermic process. More importantly, the tetragonal ZrO2 support with excellent mesostructure was well stabilized by the carbon species after introduction of K species. Therefore, K2O supported on mesoporous tetragonal zirconia (K2O/M-ZrO2-C) were successfully fabricated. The resultant mesoporous basic material presented good activity in the synthesis of dimethyl carbonate (DMC) and the DMC yield was 60.0 %, apparently higher than that (18.1 %) of the catalyst prepared without preserving carbon species (K2O/M-ZrO2). The strong basicity and the uniform mesopores of the catalyst were suggested to be contributed to the high activity. The obtained results will provide some fundamental understanding and guidance for rational catalyst design.