The effect of Si/Al ratios on the catalytic activity of CuY zeolites for DMC synthesis by oxidative carbonylation of methanol: a theoretical study

Abstract

Cu-exchanged Y zeolites with different Si/Al ratios have been investigated using a density functional theory method in order to determine the effect of Si/Al ratios on the catalytic activity for producing DMC by the oxidative carbonylation of methanol. The stable structures and catalytic activity of the CuY zeolites with different Si/Al ratios are identified. In addition, CO adsorption and the effect of CH₃O on CO adsorption, including the changes in the adsorption energy and stretching vibrational frequency for the adsorbed CO, are obtained. Our results indicate that the CuY zeolite with a Si/Al ratio = 6.5 has the highest catalytic activity for producing DMC by oxidative carbonylation of methanol among all the Si/Al ratios considered in this work, which is supported by the experimental facts. Finally, our results suggest that theoretical calculations can be used as a useful tool and provide good theoretical guidance for the experimental design of CuY zeolites.