CO2 Cycloaddition with Lignin‐Derived Oxidized Styrene Catalyzed by the Halogen‐Free N, O Co‐Doped Carbon‐Based Materials

Abstract Upgrading biochemicals is of great importance for the high‐value utilization of renewable lignocellulosic resources. In this work, we proposed a novel and efficient strategy for catalytic cycloaddition of CO 2 and lignin‐derived oxidized styrene in the presence of halogen‐free N, O co‐doped bifunctional carbon‐based materials. The catalysts were extensively characterized by Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH 3 (CO 2 )‐TPD, scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS). The catalytic performances of CO 2 cycloaddition were also investigated at various reaction conditions. When the CO 2 cycloaddition reaction was catalyzed by C 0.75 N 1 ‐180, 89% conversion of styrene oxide and 92% selectivity of styrene carbonate could be obtained, which is significantly superior than that in current techniques. Furthermore, the C 0.75 N 1 ‐180 catalyst showed good substrate adaptability and reusability, where no obvious loss of catalytic activity was exhibited even after five consecutive recycles. In addition, the kinetic property was investigated, and the catalytic mechanism was also proposed based on the results of in situ diffuse reflectance infrared Fourier transform spectroscopy. Therefore, this work provides a new route to enhance the value of the biochemicals via an atom‐economic approach.