Facile Synthesis of Bifunctional Heterogeneous Catalysts Used for the Chemical Fixation of a Low Concentration of CO2

Abstract

Mounting concerns over climate change driven by anthropogenic greenhouse gas emissions have intensified demands for technologies that enable efficient conversion of CO₂ into value-added chemicals. We report a bifunctional heterogeneous catalyst ZnBr₂@PIL-VIm-Bpy, engineered through in situ metal coordination and radical polymerization, to co-anchor Lewis acidic ZnBr₂-bipyridine complexes and nucleophilic imidazolium species within a porous ionic polymer matrix. Multimodal characterization (including solid-state NMR, XPS, FT-IR, etc.) verified the successful heterogenization of dual active sites in ZnBr₂@PIL-VIm-Bpy. The obtained material exhibits excellent catalytic activity in CO₂ cycloaddition reactions, and the conversion can reach 98.0% with a selectivity of 99.0% within 48 h at relatively mild conditions, comparable with those of homogeneous ionic liquids of VIm-Bpy and a binary catalytic system of ZnBr₂+VIm-Bpy. The catalyst ZnBr₂@PIL-VIm-Bpy can be easily separated from the product and can be reused at least 5 times without significant loss of catalytic activity, demonstrating excellent reusability and robustness. Especially, when the catalyst is applied to industrial flue gas conditions with low concentrations of CO₂, a conversion of 85.5% can still be achieved in 96 h, which even surpasses the homogeneous catalysts of VIm-Bpy and ZnBr₂+VIm-Bpy, confirming its outstanding catalytic performance in the elimination of low concentrations of CO₂. This work establishes a heterogenization strategy combining enzymatic-like cooperativity with heterogeneous catalysts’ practicality, demonstrating particular promise for point-source carbon capture–utilization integration.