Rich −NH <sub>2</sub> Mesoporous g‐C <sub>3</sub> N <sub>4</sub> Nanosheets Efficient for Cycloaddition of CO <sub>2</sub> to Epoxides without Solvent and Co‐Catalyst
Hefang Wang, Guang‐Hui Liu, Xiaojun Hao, Manhua Li, Lijia Yang, Peidong Sun, Huixin Zhang
Abstract
Abstract 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.