Surface Alkali-Modified Nano-CeO2 for Atmospherically Catalytic Polycondensation of CO2 and Diol

The polycondensation of carbon dioxide and diols under atmospheric pressure has significant appeal, thus making the study of catalysts in this process very important. Here, a series of CeO2-X catalysts (X = 9/11/13) with surface modification by basic sites was synthesized via simple impregnation in KOH solution. The structure and morphology of the CeO2-X catalysts remained unchanged after KOH treatment. However, the specific surface area of modified catalysts showed a slight decrease compared with the unmodified samples due to the notable enhancement of basic sites on the surface, resulting in improvement of CO2 adsorption capacity. Furthermore, the catalytic performance of the resultant CeO2-X catalysts was evaluated by solvent-free polymerization of 1,6-hexanediol (HDO) and CO2 at atmospheric pressure (0.1 MPa) using a well-designed reaction apparatus. As a result, the modified catalysts exhibited better performance for CO2 activation due to the existence of abundant basic sites on the surfaces, while CeO2-11 possessed the most favorable catalytic activity and displayed an enhancement of approximately 50% in production compared with that of unmodified CeO2.