Rich −NH 2 Mesoporous g‐C 3 N 4 Nanosheets Efficient for Cycloaddition of CO 2 to Epoxides without Solvent and Co‐Catalyst

Graphitic carbon nitride (g‐C 3 N 4 ) with N‐containing groups is an attractive catalyst for various CO 2 ‐activating reactions. Herein, a rich −NH 2 mesoporous g‐C 3 N 4 nanosheets catalyst was successfully prepared by thermal exfoliation from bulk g‐C 3 N 4 with porous structure using urea and melamine as precursors. With urea as precursor and bubble template, the nanosheets after thermal exfoliation showed large surface area (236.4 m 2  g −1 ), rich mesopores and −NH 2 groups, which are base sites of cycloaddition of CO 2 to epoxides. The obtained catalyst showed high catalytic performance for CO 2 cycloaddition without solvent and co‐catalyst. Propylene oxide (PO) and CO 2 cycloaddition to propylene carbonate (PC) was used as probe reaction to evaluate the catalytic performance. Under the optimal reaction conditions (130 °C, 2.5 MPa, 20 h), the conversion of PO was 97.8 % and selectivity to PC was 98.1 %. In addition, the obtained catalyst showed good suitability for various substrates in CO 2 cycloaddition and stability.