Transformation of CO2 with glycerol to glycerol carbonate by a novel ZnWO4-ZnO catalyst

ZnWO 4 -ZnO catalysts with different W content were prepared by conventional hydrothermal and wet impregnation methods and applied in the direct synthesis of glycerol carbonate from CO 2 and glycerol. The crystallite structure, texture property, morphology, redox and acid-base properties and the surface chemical situation of the catalysts were characterized by XRD, BET, TEM, H 2 -TPR, NH 3 /CO 2 -TPD and XPS. The possible activation routes of CO 2 and glycerol were analyzed with DRIFTS and FTIR. ZnWO 4 -ZnO composite catalysts showed better catalytic performances with respect to ZnO in the carbonylation of glycerol with CO 2 . The improved activity of ZnWO 4 -ZnO catalysts was associated with the formation of ZnWO 4 , the interaction between ZnWO 4 and ZnO, and the enhanced moderate acidic property. DIRFTS results showed that chelating bidentate carbonate species was the main adsorption pattern for CO 2 on ZnO, while the introduction of W led to the bridged bidentate carbonate, which became the main adsorption pattern on ZnWO 4 -ZnO. As for the activation of glycerol, zinc glycerolate played an important role in the reaction process. Based on the reaction and characterization results, a plausible reaction route involved a seven-membered ring esters intermediate was suggested for the reaction of CO 2 and glycerol over ZnWO 4 -ZnO catalysts.