Controllable synthesis of Co/NC catalysts with high-density Co–Nx active sites derived from Co/Zn-ZIF for cyclopropanation

Abstract

Novel Co/NC heterogeneous catalysts were prepared by simply employing self-made Co/Zn-ZIF (zeolitic imidazolate framework) through pyrolysis. The samples were characterized by XRD, XPS, Raman, TEM and BET, and were successfully applied in a cyclopropanation reaction with a yield of 85%. Furthermore, this one-pot synthesized catalyst could be recycled several times without apparent deactivation. The content of Co–N_x active sites could be modified by adjusting the Co/Zn molar ratio of the ZIF precursor. The generation of Co–N_x could be attributed to the evaporation of Zn species, which provides rich micropores.