Upgraded Heterogenization of Homogeneous Catalytic Systems by Hollow Porous Organic Frameworks with Hierarchical Porous Shell for Efficient Carbon Dioxide Conversion

Abstract

AbstractThe heterogenization of homogeneous catalysts is one promising approach to achieve recyclability and reusability of catalyst, while it inevitably tied to the poorer accessibility of reactants and less effectiveness of catalytic sites. Herein, we present a hollow porous organic frameworks (HPOFs) with unique large hollow cavity, hierarchical porous shell and well dispersed catalytic active sites. The shell thickness of HPOFs is controllable via tune the amount of building blocks. Compared with their solid counterpart, the hollow interior of HPOFs accelerated the mass transfer of reactants into catalytic sites and products out of catalyst skeleton. Meanwhile, the hierarchical porous thin shell exposed more active catalytic species to interact with substrate molecules. These advantages enable HPOFs to best maintain the performance of homogeneous counterpart after heterogenization. The relationship of catalytic activity and hollow structure was investigated by the cycloaddition reaction of CO2 with 2‐(chloromethyl)oxirane in the absence of solvents, co‐catalysts and additives. The catalytic activity increased gradually with the decrease of shell thickness. This work provides a new insight for the development of heterogenization of homogeneous catalysts based on hollow porous organic frameworks.