Photocatalytic performance of ZIF-8/g-C₃N₄ composite for deep oxidation of NO

g-C₃N₄, ZIF-8 and ZIF-8/g-C₃N₄ composite photocatalysts with different mass ratios were prepared by thermal polymerization method and in-situ deposition method, respectively. The structural properties of prepared samples were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS), etc. The results showed that the ZIF-8/g-C₃N₄ composite did not destroy the original crystal structure and morphology of ZIF-8 and g-C₃N₄, and ZIF-8 formed a heterojunction with g-C₃N₄. The BET specific surface area of ZIF-8/g-C₃N₄ was improved more than 30 times compared with g-C₃N₄. The results of photocatalytic oxidation of NO showed that 12.5%-ZIF-8/g-C₃N₄ exhibited the best removal efficiency of NO and no toxic intermediate NO₂ production, and it had the most excellent photocatalytic activity with the nitric oxide removal efficiency of 55.1%. The mechanism study showed that the formed heterostructure not only inhibited the recombination of photogenerated charge carriers, but also promoted the absorption of visible light and the adsorption of reactant molecular NO due to the synergy between ZIF-8 and g-C₃N₄, thus improving the photocatalytic oxidation performance of NO.