Core-shell nanospheres of SiO₂@ZIF-67 with varying sizes demonstrate high performance as catalysts for CO₂ cycloaddition

The primary objective of this study is to investigate the catalytic activity of metal–organic framework (MOF) materials, particularly those designed with core–shell structures. The study will focus on how variations in particle sizes of core–shell catalysts influence the catalytic performance. A key application under investigation is their ability to facilitate the cycloaddition of carbon dioxide (CO₂) with epoxides, a reaction that holds significant promise for the synthesis of cyclic carbonates. Results show that reducing the size of silica spheres increases the specific surface area and improves catalytic activity. SiO₂-1μm@ZIF-67 exhibited the highest turnover frequency (TOF) of 52, significantly outperforming other samples. Adding secondary metals, such as Fe and Cu, maintained the structural integrity of ZIF-67 and the bimetallic core–shell structure demonstrated excellent stability and reusability, making it a promising candidate for industrial applications. This process not only provides a sustainable pathway for CO₂ utilization but also aligns with global efforts to mitigate carbon emissions through chemical recycling. By systematically analyzing different MOF particle sizes, we aim to gain insights into the relationship between size, structure, and catalytic efficiency, thereby advancing the development of more effective catalysts for CO₂ transformation.