CuxOy@COF: An efficient heterogeneous catalyst system for CO2 cycloadditions under ambient conditions

Synthesis of cyclic carbonates via CO2 cycloaddition reaction with epoxides is one of the promising strategies to valorize greenhouse gas CO2, thereby fixing it to the value-added chemicals. In this study, uniform copper oxide nanoparticles (Cu2O, Cu4O3) with variable oxidation states are stabilized by functionalized covalent organic frameworks (COF) and effectively utilized as a catalyst for the synthesis of cyclic carbonates under ambient temperature and atmospheric pressure. Characterization techniques e.g. powdered X-ray Diffraction (PXRD), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR) and nitrogen physisorption (BET) coupled with DFT studies predict that the copper oxide nanoparticles are anchored on the mesochannels of covalent organic frameworks through a covalent-coordinate linkage. The catalyst exhibits significantly high turn over numbers (TON, order of 10(5)) and more than 99% selectivity towards synthesis of cyclic carbonates with exceptional recyclability.