Direct copolymerization of carbon dioxide and 1,4-butanediol enhanced by ceria nanorod catalyst

Abstract Direct copolymerization of CO2 and 1,4-butanediol to yield poly(butylene carbonate) oligomers has been recently realized using CeO2 as a catalyst and 2-cyanopyridine as a dehydrating agent. In this study, CeO2 nanorod and nanocube were synthesized, characterized, and compared their catalytic activities with commercial CeO2 nanoparticle and submicronparticle. Reaction testing reveals that CeO2 nanorod exhibits a much higher yield of polycarbonate oligomer than other CeO2 catalysts. Surface characterizations indicate that CeO2 nanorod displays a significantly higher CO2 uptake and stronger interactions with CO2, properties that could be beneficial to activate stable CO2 molecule. In-situ infrared spectroscopy suggests that bidentate carbonate, i.e., CO2 adsorbs over the CeO2 surface with an oxygen atom and an oxygen vacancy coordinated with a cerium atom, is the key intermediate associated with the observed catalytic activities. These results manifest the importance of surface oxygen vacancy of CeO2 for activating CO2 to proceed non-reductive conversion.