Tailored covalent organic frameworks for simultaneously capturing and converting CO2 into cyclic carbonates

Abstract

The catalytic cycloaddition of CO₂ to epoxides is one of the most promising and green pathways for CO₂ utilization in industry. In recent years, covalent organic frameworks (COFs) as a flourishing class of organic porous materials have been widely used for efficient capture and conversion of CO₂. By virtue of the flexible regulation of pore parameters and the task-specific introduction of catalytically active components into their crystalline structures, well-designed COFs with tailored functions and stable and ordered frameworks may be a viable alternative to metal–organic frameworks (MOFs) so as to meet the multifaceted requirements of CO₂ activation and transformation. This review describes the recent advances made with regard to the design and synthesis of tailored COFs for simultaneously capturing and converting CO₂ into cyclic carbonates. Given the presence of different kinds of catalytically active sites, we have divided recently reported COFs into four main categories, i.e., covalent triazine frameworks (CTFs), hydroxyl-decorated COFs (hydroxyl COFs), metal-functionalized COFs (metal COFs) and ionic liquid-modified COFs (ionic COFs). The rational design of organic polymeric monomers and the wise choice of the pre-synthesis or post-modification strategy have been extensively emphasized and discussed here in detail. We expect that valuable guidance and a unique overview may be provided towards CO₂ conversion into cyclic carbonates, thereby developing numerous function-led COFs with excellent industrial application prospects.