Synthesis And Photocatalytic Performance Of The G-C₃N₄ And G-C₃N₄ Nanosheets-based Composite Materials

The environmental pollution control based photocatalysis was faced with technological problem,such as low visible-light quantum efficiency,bad utilization rate of solar energy,catalytic activity and short lifetime.These problems limit the development of photocatalytic materials in environmental governance field.In order to solve these problems,this paper takes organic semiconductor g-C₃N₄ as the main research object,design and synthesis of different nano-morphologies of g-O3N4 materials.Firstly,bulk g-C3N was synthesised through thermal oxidation,then modified g-C₃N₄ by creating nano-morphology and recombinating with CdS semiconductor materials,and the photocatalytic efficiency of the g-C₃N₄ material under visible light was improved.The main contents are as follows:1)Preparation of bulk g-C₃N₄,study the physicochemical property and photocatalytic performance of bulk g-C₃N₄:through thermal polymerization of the organic precursors to prepare bulk g-C₃N₄.The experimental results show that the bulk g-C₃N₄ with poor block structure and low photocatalytic performance.To improve the photocatalytic activity of the bulk g-C₃N₄,high temperature oxidation operation was applied;and the modified g-C₃N₄ showed the decreased of material size and improved photocatalytic performance.2)Design and synthesis of different nano-morphology g-C₃N₄ and characterization and photocatalytic tests on the corresponding g-C₃N₄:nano-casting of cyanoguanidine precursor to prepare mesoporous morphology g-C₃N₄.Choosing urea as precursor and manipulation of polycondensation process to prepare the honeycomb porous morphology of g-C₃N₄?HP-CN?,then using liquid-phase exfoliation technology to delaminate HP-CN into curly leaf-like morphology of g-O3N4 nanosheets?CL-CN?.The photocatalytic results show that the mesoporous g-C₃N₄ and CL-CN can degrade the dye completely within 30 min under UV irradiation,and exhibit high efficiency and stable photocatalytic performance under visible light.3)The preparation of CNNS/CdS QDs composite photocatalyst and study its photocatalytic performance:copolymerization urea and 2,4,6-triaminopyrimidine to prepare the g-C₃N₄ nanosheets?CNNS?;then choosing CNNS as the substrate material,using simple solvothermal method to synthesize CNNS/CdS QDs composite photocatalyst and characterized it by different chemical instrument.The photocatalytic performance of composite materials was evaluated by photocatalytic degradation test.The results show that the method to prepare CNNS based composite materials is simple and efficient,the CNNS/CdS QDs-2 photacatalyst has efficient and stable photocatalytic performance.