Confinement of halide ions in Mg-Beta zeolites enables synergistic catalysis for CO2 cycloaddition

The confinement of metal-based matrix such as clusters, particles and even isolated single atoms in zeolite framework was intensively reported, while it was highly untoward to realize this goal for non-metallic ions due to the mutually-exclusive electrostatic interaction between the zeolite framework with negative charges and non-metallic anions. Herein, confinement of iodide ions in Mg-Beta zeolites (I@Mg-Beta) was successfully accomplished via the methodology of structural reconstruction, whose physicochemical property, channel connectivity as well as the location of Mg 2+ and I - ions were investigated systematically. It was found that Mg 2+ ions were located in the zeolitic framework and I - ions were mainly confined in Mg-Beta zeolite via the electrostatic interaction with tetraethylammonium cations. The establishment of structure–function relationship in CO 2 cycloaddition reaction with epoxides indicated the presence of synergistic effect between framework Mg 2+ ions and confined I - ions. The immobilisation of halide ions onto a zeolite support enabled it the recoverable ability from reaction systems, giving rise to relatively stable reusability. The catalytic transformation of CO 2 cycloaddition with epoxides in this work was devoted to ameliorate environmental stress from anthropogenic greenhouse gases of CO 2 by means of elaborately constructing metallosilicate zeolite confined non-metallic catalysts with dual functions.