Novel Carbon Nitride/Metal Oxide Nanocomposites as Efficient and Robust Catalysts for Coupling of CO2 and Epoxides

Several environmentally benign graphitic carbon nitride (g-C3N4)-based nanocomposites with Lewis acid-base dual functionalities were developed through the pyrolysis of deep-eutectic solvents (DESs). They were used as heterogeneous catalysts for cycloaddition of CO2 to epoxides. The catalysts' structures and different process conditions were optimized, and a comparison of the catalytic activity was made with reported heterogeneous catalysts. Moreover, the catalyst reusability and applicability to different epoxides were examined. The results showed that the 2.0Zn@g-C3N4-550 combining with tetrabutylammonium bromide (TBAB) could efficiently and selectively convert CO2 into the desired products under the conditions of 90 degrees C, 1.5 MPa CO2 for 3.0 h. In addition, no obvious deactivation was observed after the catalyst was reused for five cycles. Based on the experimental results, a possible synergistic catalytic mechanism was finally proposed.

Automated summary

Several environmentally benign graphitic carbon nitride (g-C3N4)-based nanocomposites with Lewis acid-base dual functionalities were developed through the pyrolysis of deep-eutectic solvents (DESs). These catalysts were used for the cycloaddition of CO2 to epoxides, showing high efficiency and selectivity under specific conditions. The catalysts also demonstrated good reusability and applicability to different epoxides, with a proposed synergistic catalytic mechanism based on experimental results.