Abstract: The supported catalysts Ni/g-C3N4 with different Ni-doped contents were prepared by impregnation route, and performed for the UV-light driven photodegredation performance in methylene blue.The as-obtained Ni/g-C3N4 samples were characterized by several techniques, including XRD, FT-IR, SEM, TEM, XPS, N2-adsorption, and ICP-OES.The results suggest that the photocatalytic activity of Ni/g-C3N4 catalysts increase with the increasing doping content of metallic nickel nanoparticles while decease with the increasing concentration of methylene blue.The 4-Ni/g-C3N4 sample with Ni-doped dosage of 4.0wt; presented the excellent photocatalytic activity and photodegradation stability.It's ascribe to the active species of superoxide radical (O2·-), hole (h+), and hydroxyl radical (·OH) produced by 4-Ni/g-C3N4 sample in photocatalytic degradation system, of which the superoxide radical is the most important material.Metallic Ni0 species and O2 molecules are converted to the active Ni2+ ions and O2·-radicals under photoproduced ions, respectively.These excited species facilitate the separation of photogenerated electron-hole pairs and reduce the electron-hole recombination, leading to the enhanced in phtocatalytic degradation of methylene blue under visible light irradiation.

Key words: The supported catalysts Ni/g-C3N4 with different Ni-doped contents were prepared by impregnation route, and performed for the UV-light driven photodegredation performance in methylene blue.The as-obtained Ni/g-C3N4 samples were characterized by several techniques, including XRD, FT-IR, SEM, TEM, XPS, N2-adsorption, and ICP-OES.The results suggest that the photocatalytic activity of Ni/g-C3N4 catalysts increase with the increasing doping content of metallic nickel nanoparticles while decease with the increasing concentration of methylene blue.The 4-Ni/g-C3N4 sample with Ni-doped dosage of 4.0wt; presented the excellent photocatalytic activity and photodegradation stability.It's ascribe to the active species of superoxide radical (O2·-), hole (h+), and hydroxyl radical (·OH) produced by 4-Ni/g-C3N4 sample in photocatalytic degradation system, of which the superoxide radical is the most important material.Metallic Ni0 species and O2 molecules are converted to the active Ni2+ ions and O2·-radicals under photoproduced ions, respectively.These excited species facilitate the separation of photogenerated electron-hole pairs and reduce the electron-hole recombination, leading to the enhanced in phtocatalytic degradation of methylene blue under visible light irradiation.