Solid and Hollow CeO2 Nanoparticles as Catalyst for the Synthesis of Dimethyl Carbonate from CO2 and Methanol

Abstract

The current reaction mechanism of cerium dioxide (CeO2) catalyzing the direct synthesis of dimethyl carbonate (DMC) from carbon dioxide (CO2) and methanol remains unclear. In this study, we prepared hollow nanospheres of CeO2 with different shell thicknesses (CeO2–S–x h) by controlling the Ostwald ripening time to investigate the role of surface hydroxyl groups in the catalytic process. Among these, the DMC formation rate of CeO2–S–24 h was 20.6 mmol g cat–1 h–1, which is 1.5 times that of CeO2–S–4 h. Combining X-ray photoelectron spectroscopy (XPS) etching and in situ Fourier-transform infrared spectroscopy (FTIR) analysis, we found that an appropriate shell thickness can effectively suppress the inhibition of hydroxyl group conversion caused by oxygen vacancy (Vo) migration, thereby promoting the transformation of monomethyl carbonate (MMC) to methoxycarbonyl (MC) and enhancing the DMC formation rate. This study provides insights into the structural design of CeO2-based catalytic materials and reveals the critical role of surface hydroxyl groups in the synthesis of DMC.