Preparation And Photocatalytic Properties Of G-C₃N₄/ZnO Photocatalysts

In this thesis,the photocatalytic properties of the composite photocatalysts were improved by doping the 2D-g-C₃N₄.The g-C₃N₄ could improve the separation and migration efficiency of photogenerated carriers of g-C₃N₄/ZnO photocatalysts.On the basis of previous research,three different morphological composite photocatalysts were prepared.The linear of composite photocatalysts exhibited the highest photocatalytic activity.On the basis of the above two systems.The new H⁺-g-C₃N₄were produced and doped in the rod g-C₃N₄/ZnO photocatalysts.the sunlight absorption range were broadened.The rod of H⁺-g-C₃N₄/ZnO photocatalysts could absorb the visible light without precious metal.The photocatalysts were characterized by XRD,scanning electron microscopy,UV-Vis solid diffuse reflection,fluorescence spectroscopy,hydrogen production by photolysis,and photoelectrochemical properties.?1?H⁺-g-C₃N₄ were displaced to the edge of the grain boundary because of recrystallization of NH₄Cl.Then H⁺-g-C₃N₄ were doped in the g-C₃N₄/ZnO photocatalysts.The separation and migration efficiency of photogenerated carriers of H⁺-g-C₃N₄/ZnO photocatalysts were improved.The optimal incorporation of two-dimensional flake carbon nitride?H⁺-g-C₃N₄?was investigated,and the sample of1-1-5-0.2 was obtained and performed the highest photocatalytic water splitting efficiency.Under the full light,the amount of H₂ evolution were 12.32 mmol/g,and the rate of H₂ production were 1.44 mmol/?g·h?.It was 54 times the amount of H₂production of ZnO,and the photogenerated current was 10 times of ZnO.?2?Three different morphologies of g-C₃N₄/ZnO were prepared.The purpose was to find the most exposed reaction center.Then the liner of H⁺-g-C₃N₄/ZnO photocatalysts had the most reaction center.Because two-dimensional H⁺-g-C₃N₄ can be better combined with zinc oxide.Under the full light,the amount of H₂ evolution was 15.139 mmol/g,and the rate of H₂ production was 1.815 mmol/?g·h?.?3?The layer of carbon nitride was prepared and the H⁺-g-C₃N₄/ZnO photocatalysts were broadened the spectral absorption range.In this system,the linear H⁺-g-C₃N₄/ZnO photocatalysts could absorb the visible light.Under the full light the amount of H₂ evolution was 7.81 mmol/g,and the rate of H₂ production was 1.30mmol/?g·h?.The photocatalytic water splitting hydrogen production under the visible light without the presence of a precious metal promoter.The amount of H₂ evolution was 40?mol/g within 6h.