Facile reflux preparation of defective mesoporous ceria nanorod with superior catalytic activity for direct carbon dioxide conversion into dimethyl carbonate

Nanostructured ceria has drawn a great interest in sustainable catalysis research due to its unique oxygen release/storage capability. However, the conventional hydrothermal method for ceria preparation requires harsh conditions, which restrict its applications. Here we report a facile reflux process that is able to synthesize ceria nanorods in a mild environment. Particularly, it is found that the rapid reflux synthesis enables the formation of defective mesoporous structure in ceria catalysts, which enriches the surface with abundant trivalent Ce ions and oxygen vacancy sites. These features significantly improve the catalytic activity of ceria nanorod in synthesizing dimethyl carbonate (DMC) from methanol carbonation. Our result also reveals that the shorter reflux period for catalyst preparation can lead to a higher DMC yield due to the larger amounts of mesoporous defects and the higher concentrations of oxygen vacancies. Moreover, the reflux-synthesized ceria nanorods exhibit over 3 times higher DMC yield than hydrothermal counterpart, which can be attributed to their superior CO2 adsorption and activation capabilities as evidenced by combined surface characterizations. This study presents a practical strategy to synthesize CeO2 catalysts with exceptional catalytic activity by creating a defective mesoporous surface structure in a highly-efficient manner.