A dual-ionic hyper-crosslinked polymer for efficient CO₂ fixation and conversion

It is of great significance for reducing carbon emissions and protecting the environment to convert carbon dioxide (CO2) into high-value chemicals. The cycloaddition of CO2 with epoxides to prepare cyclic carbonates is a very attractive and potential approach. However, due to the inherent chemical inertness of CO2, the development of highly efficient, metal-free, solvent-free, and co-catalyst-free heterogeneous catalysts is crucial. Herein, a dualionic system hyper-cross-linked polymer (HIP-COOH-TMG) was synthesized by a post-synthetic strategy. HIPCOOH-TMG with multiple active sites was characterized by FT-IR, XPS and other characterizations. HIPCOOH-TMG exhibited the excellent catalytic activity than HIP-COOH for the CO2 cycloaddition, the yield and selectivity of chloropropene carbonate (CC) reached 99 % within 8 h at 110 degrees C under 1 MPa CO2 pressure. In addition, HIP-COOH-TMG is easily separated from the product, has good recyclability and structural stability, and exhibits high activity towards a series of epoxides. Finally, density functional theory (DFT) calculations reveal the synergistic catalytic mechanism of hydrogen bond donors (HBDs) groups 1/4 NH2+ sites and N sites activation of HIP-COOH-TMG, providing a reference for the design of metal-free, co-catalyst-free, and solventfree heterogeneous catalysts.