Synthesis of glycerol carbonate from glycerol and diethyl carbonate over Ce-NiO catalyst: The role of multiphase Ni

A series of Ce-NiO catalysts prepared by co-precipitation method were tested for glycerol transesterification with diethyl carbonate (DEC) to produce glycerol carbonate (GC). The microstructural and physicochemical properties of the catalysts were determined by XRD , XPS , SEM, EDX, CO 2 -TPD, N 2 -adsorption, FT-IR, and TG-DTG. The results showed that the particle size (100–350 nm) of the Ce-NiO was smaller than that of pure NiO (400–900 nm), suggesting addition of Ce in the catalyst synthesis could lessen the aggregation or facilitate the dispersion of NiO particles. The highest catalyst activity was observed over the Ce-NiO catalyst with Ce/Ni atomic ratio of 0.2 and calcined at 400 °C. 94.14% of glycerol conversion and 90.95% selectivity to GC were obtained over this catalyst under the optimum conditions (5 wt.% catalyst of glycerol, 85 °C, 8 h, glycerol/DEC ratio of 1:3). This catalyst can be reused up to three cycles with a slight decrease in its catalytic activity. It was found the well dispersed NiO particles and the strong basic sites derived from the substitution of Ce 4+ by Ni 2+ in the CeO 2 lattices synergistically promoted the glycerol conversion.