Abstract: Graphitic carbon nitride (g-C3N4) was prepared by the thermal condensation of melamine.Then, A g-C3N4/CuO nano composite materials were prepared using Cu(NO3)2 and g-C3N4 as raw material under hydrothermal method in present of amount of ammonia with deionized water and anhydrous ethanol as solvent.The obtained photocatalyst was characterized by field emission scanning electron microscope (FE-SEM), photoelectron spectrometer (XPS) and uv-vis diffuse reflection (UV-Vis-DRS) and fluorescence spectroscopy (PL).According to the XRD, SEM and XPS test result, micro spherical CuO and g-C3N4 closely together;the UV and PL spectra show that the combination of CuO and g-C3N4 composite can expand the scope of visible light absorption and slows down the compound rate of electrons and holes.The degradation of methyl orange (MO) aqueous solution was used to evaluate the photocatalytic activity of 70-g-C3N4/CuO under visible light irradiation.The results show that in the absence of hydrogen peroxide (H2O2) system, the degradation rate of MO remains 85; after 4 h of light reaction,but the existence of H2O2 system, the photodecomposition rate of MO reached 96; after 1 h light reaction.Through laboratory experiments on the trapping free radicals, hydroxyl free radical and hole played an important role in the process of degradation of MO.After four times of circulation, the basic for the degradation of MO rate still reached 90;.Thus the g-C3N4/CuO material had good photocatalytic and stability.

Key words: Graphitic carbon nitride (g-C3N4) was prepared by the thermal condensation of melamine.Then, A g-C3N4/CuO nano composite materials were prepared using Cu(NO3)2 and g-C3N4 as raw material under hydrothermal method in present of amount of ammonia with deionized water and anhydrous ethanol as solvent.The obtained photocatalyst was characterized by field emission scanning electron microscope (FE-SEM), photoelectron spectrometer (XPS) and uv-vis diffuse reflection (UV-Vis-DRS) and fluorescence spectroscopy (PL).According to the XRD, SEM and XPS test result, micro spherical CuO and g-C3N4 closely together;the UV and PL spectra show that the combination of CuO and g-C3N4 composite can expand the scope of visible light absorption and slows down the compound rate of electrons and holes.The degradation of methyl orange (MO) aqueous solution was used to evaluate the photocatalytic activity of 70-g-C3N4/CuO under visible light irradiation.The results show that in the absence of hydrogen peroxide (H2O2) system, the degradation rate of MO remains 85; after 4 h of light reaction,but the existence of H2O2 system, the photodecomposition rate of MO reached 96; after 1 h light reaction.Through laboratory experiments on the trapping free radicals, hydroxyl free radical and hole played an important role in the process of degradation of MO.After four times of circulation, the basic for the degradation of MO rate still reached 90;.Thus the g-C3N4/CuO material had good photocatalytic and stability.