Manipulation of Oxygen Vacancy on a CeO₂ Catalyst for the Carbonylation of Glycerol with CO₂

Cerium dioxide (CeO₂) with different morphologies was synthesized via a hydrothermal method and applied to the carbonylation of glycerol with CO₂. Subsequent characterization through H₂-TPR and catalytic activity tests demonstrated that CeO₂ nanorods exhibited the highest oxygen storage/release capacity as well as enhanced catalytic performance compared to other morphologies. CeO₂ nanorods were thus further modified through hydrogen reduction at varying temperatures, aiming to tune the density of the oxygen vacancies. Characterization via BET, NH₃-TPD, CO₂-TPD, XPS, and ESR indicated that variations in morphology and reduction temperature influenced the microstructural characteristics and the strength of the acid-base sites of the catalysts. Notably, hydrogen reduction created more oxygen vacancies in the CeO₂ nanorods, with the concentration of these vacancies increasing with higher reduction temperatures. Furthermore, the catalytic activity of CeO₂ in glycerol carbonylation with CO₂ showed a positive correlation with the concentration of oxygen vacancies. Optimizing CeO₂ catalysts can enhance its performance in activating CO₂, providing new ideas for industrial CO₂ resource utilization and carbon capture technology development.