Ceria nanostructured catalysts for conversion of methanol and carbon dioxide to dimethyl carbonate

In this study, three different shapes of ceria (CeO2) nanostructures (e.g., nanooctahedra, nanocubes and nanorods) were synthesized via the hydrothermal method and screened for carbonylation reaction. Of these three shapes of nanostructures, the nanorod was doped with metals such as Ca, Ni, Cu, and Co by wet impregnation method. All materials were characterized by XRD, NH3/CO2-TPD, XRF, FTIR and N2 physorption to determine the crystal size and phases, acid-base properties, metal loading, and surface properties. The obtained materials were employed as catalysts for the activation of Carbon Dioxide (CO2) and methanol carbonylation reaction to dimethyl carbonate (DMC) at 140 °C, 30 bars and 3 h. It was found that the shape of the nanostructured ceria has a major effect on DMC yield with the CeO2 nanorod catalyst producing the highest DMC yield (1.6 mmol) followed by nanooctahedra (0.66 mmol) and nanocubes (0.32 mmol). All catalytic tests showed 100 % DMC selectivity, and the trends of catalytic activity over ceria doped metal oxide decreased in the following order: CeO2 \u3e CoO/CeO2 \u3e NiO/CeO2 \u3e CaO/CeO2 \u3e CuO/CeO2. The reusability of the catalyst was tested by carrying out four consecutive cycle --Abstract, page iii