Zn-Doped CeO₂ Nanorods for Glycerol Carbonylation with CO₂

Abstract

The chemical industry is facing a major challenge in the design of heterogeneous catalysts for CO2 activation and valorization. The modification of CeO2 nanorods with divalent transition metal ions (M = Zn, Cu, and Ni) resulted in the enhancement of oxygen vacancies, which improved the activation of CO2. The results revealed that based on the electronic properties of dopants and their coordination with the support, the nature of active sites can be tuned on the surface of the catalyst. Zn-doped CeO2 nanorods exhibited significantly higher activity for glycerol carbonate synthesis as Zn enhances the surface reducibility of Ce4+. 2-cyanopyridine (dehydrating agent) reacts with water to give 2-picolinamide, which influences the conversion of glycerol. The catalysts were characterized extensively by X-ray diffraction, transmission electron microscopy, N2-sorption, X-ray photoelectron spectroscopy, H2-temperature programmed reduction, Raman spectroscopy, and NH3–CO2 temperature programmed desorption techniques. Under optimized conditions; 90.4% glycerol conversion and 89.5% yield towards glycerol carbonate were achieved.