Design of carbonized melamine sponge@MOFs composites bearing diverse acid-base properties for boosting thermal and solar-driven CO2 cycloaddition

Integrating dual Lewis acid and base as well as rational hierarchical pore structure in one catalyst is favorable to significantly boost the CO2 cycloaddition reaction at mild conditions. In this regard, carbonized melamine sponge (CMS) featuring a highly porous network, rich nitrogen doping and excellent photothermal capability is employed as the ideal host for the construction of CMS@MOFs (namely, MIL-88-NH2 and ZIF-8-NH2) composites with diverse acid-base properties. Results show that all the obtained composites exhibited a satisfactory CO2 adsorbing capacity (33-54 cm(3)/g) and delivered a remarkable yield of target cyclic carbonate at either mild thermal conditions (0.1 MPa CO2 and 80 degrees C) or under light irradiation (light intensity: similar to 350 mW/cm(2)) at room temperature. Even with diluted CO2 (15 vol. % CO2), high yields of 80-82 % are achievable. Moreover, the used catalysts can be easily recycled from reaction systems, leading to a good recyclability.