Oxygen Vacancy Promoting Dimethyl Carbonate Synthesis from CO 2 and Methanol over Zr-Doped CeO 2 Nanorods

The synthesis of dimethyl carbonate (DMC) from CO 2 and methanol by Zr-doped CeO 2 nanorods with different ratios of Zr/Ce has been studied at 6.8 MPa and 140 °C. The catalysts were characterized extensively by TEM, XRD, N 2 adsorption, Raman spectroscopy, UV–vis spectroscopy, XPS, CO 2 -TPD, and in situ FTIR techniques. Doping of Zr atoms into the ceria lattice produced a fluorite-like solid solution, promoting the formation of oxygen vacancy sites. Zr-doped CeO 2 nanorods exhibited significantly more oxygen vacancy sites than pure CeO 2 nanorods. Zr 0.1 Ce nanorods which exhibited DMC synthesis activity also possess the highest concentration of oxygen vacancy sites. In situ FTIR studies further revealed that CO 2 can adsorb on the oxygen vacancy to form bidentate carbonate and as intermediate to participate in the reaction. This study presents a strategy to design a high-efficiency CeO 2 -based catalysts by controlling the concentration of the surface oxygen vacancies.