In Situ Pyrolysis of ZIF-67 to Construct Co2N0.67@ZIF-67 for Photocatalytic CO2 Cycloaddition Reaction.

The development of heterogeneous catalysts with abundant active sites is pivotal for enhancing the efficiency of photothermal CO₂ conversion. Herein, we report the construction of Co₂N_0.67@ZIF-67 through the in situ pyrolysis of ZIF-67 under low-temperature pyrolysis conditions. During the pyrolysis process, the crystal structure of ZIF-67 is predominantly preserved concurrently with the formation of Co₂N_0.67 nanoparticles (NPs) within the ZIF-67 pores. The optimal catalyst Co₂N_0.67@ZIF-67(450,2) not only possesses high photothermal efficiency but also can efficiently activate CO₂. Benefiting from these characteristics, Co₂N_0.67@ZIF-67(450,2) exhibited significant catalytic activity in the photocatalytic cycloaddition of CO₂ and epichlorohydrin. The yield of (chloromethyl)ethylene carbonate reached 95%, which is more than 4 times higher than that of ZIF-67 under visible light irradiation (300 W·m² Xe lamp, 3 h). This study could offer an alternative approach to enhance the photocatalytic activity of MOFs through low-temperature pyrolysis.