Preparation And Photocatalysic Performance Of G-C₃N₄-based Nanocomposites

The environment and energy problems have become the main factors that restain the development of the society.Photocatalysis technique as a promising and green technology,it has received extensive attention in the energy and environment field.Graphitic carbon nitride（g-C₃N₄）has some merits.For example,g-C₃N₄ possesses the low band gap,low price,high chemical and physical stability.Therefore,g-C₃N₄ is considered a potential free-metal photocatalyst.However,the photocatalytic activity and the practice application of g-C₃N₄ are restrained owing to the low electrical conductivity,small specific surface area and high recombination rate of charge carriers.Based on those facts,the shortages of g-C₃N₄ may be resolved by constructing the heterojunction with other materials（semiconductor photocatalyst,graphene,noble metal and so on）.So,we use the g-C₃N₄,graphene and noble metal as the reactant to construct the heterojunction.The g-C₃N₄ was prepared by pyrolysing the urea at 550 ℃ for 3 hours.Then the g-C₃N₄/grapnene（rGO）was prepared by the simple hydrothermal method.The structure of g-C₃N₄/rGO was stackable.The ptotocatalytic performance of g-C₃N₄/rGO that contained the different content graphene was studied by degrading the Rhodamine B（RhB）under visible-light irradiation.Under the illumination of visible-light,g-C₃N₄/rGO nanocomposites with 10% graphene can degrade 92% RhB in 120 min.The degradation efficiency of 4-CP could reached 91% in 80 min.Furthermore,The recycling test indicated that g-C₃N₄/rGO sample does not significantly decrease through the four cycles and had a better stability.The three dimensional g-C₃N₄/graphene（rGO）/Palladium（Pd）nanocomposites were prepared by the pyrolysis-hydrothermal two step method.Pd nanoparticles were uniformly distributed in the surface of graphene and g-C₃N₄ with the diameters of ¹0 nm.The photocatalytic activity of g-C₃N₄/（rGO）/Pd nanocomposites was measured by the degradation of RhB solution under visible-light irradiation（λ>400 nm）.The results indicated that g-C₃N₄/rGO/Pd nanocomposites can degrade 90% RhB in 140 min under the visible-light irradiation.In addition,the recycling experiment demonstrated that the nanocomposite still remains good photocatalytic stability after four cycle experiments.