Preparation And Photocatalytic Performance Of Graphite Phase Carbon Nitride Hybrid Photocatalysts

In recent years,with the gradual aggravation of environmental pollution,photocatalysis as a green environmental treatment method has gradually attracted people's attention.Graphite carbon nitride?g-C₃N₄?has been widely used in photocatalytic reaction because of its suitable valence band structure?Eg=2.7 eV?,excellent thermal and chemical stability,facile preparation process and non-toxicity.However,the g-C₃N₄ prepared by traditional thermal polymerization method still has the shortcomings such as the small specific surface area,the high photogenerated electron and photogenerated hole recombination rate,which seriously restricts the wide application of g-C₃N₄.In order to overcome these shortcomings,a series of g-C₃N₄/ZnO composite photocatalysts were synthesized by the combination of g-C₃N₄ prepared by traditional polymerization method with different content of ZnO.Then,the oxygen-doped mesoporous graphite phase carbon nitride?O-mpg-C₃N₄?with large specific surface area was prepared by using the bubble soft template method after solvent heat treatment with H₂O₂.?1?The pompon g-C₃N₄/ZnO composite photocatalyst was prepared by two-step method,and its physicochemical properties were investigated by various characterizations.The results show that the pompon g-C₃N₄/ZnO is a heterogeneous structure formed by flake-wrapped pompon ZnO.Among the composite photocatalyst,the pompon ZnO has a larger specific surface area?41.81m²/g?and can provide more reactive sites for the composite photocatalyst.The introduction of g-C₃N₄ can effectively expand the absorption range of the composite photocatalyst.At the same time,the heterostructure formed between g-C₃N₄ and ZnO can effectively reduce the photogenerated electron and photogenerated hole recombination rate.The photocatalytic performance of the composite photocatalyst was determined by the degradation of Rhodamine B?RhB?in visible light and the stability of the composite photocatalyst was determined by cycling five times under visible light.The optimum doping amount of carbon nitride is 10%.?2?O-mpg-C₃N₄ was prepared by simple thermal polymerization-solvothermal method for the first time and its physical and chemical properties were measured by various characterization methods.The results show that the prepared samples are flake structures with many holes,and the doped oxygen in the lattice comes from C-O or N-C-O chemical bonds.Based on the photocatalytic degradation of Rhodamine B?RhB?and Methyl Orange?MO?under visible light,the photocatalytic performance of O-mpg-C₃N₄ is much better than that of g-C₃N₄ and mpg-C₃N₄.The improvement of photocatalytic activity is mainly due to the increase of active sites,the shorter electron migration distance and the wider light absorption range.