Synthesis And Representation Of Fe₃O₄/C-g-C₃N₄ Complexes For Visible Light Catalysis

Photocatalysis has attracted extensive attention because of its non-pollution and using sunlight.Among them,as a result of graphite carbon nitride?g-C₃N₄?has the characteristics of visible light response,physically and chemically stable,easy preparation and so on,it has become research hotspot in the field of photocatalytic materials.However,pure g-C₃N₄ has the disadvantages of small specific surface area and high recombination rate of photogenerated electron-hole,the photocatalytic efficiency of pure g-C₃N₄ is not satisfying.In recent years many,researcher used different methods to modify g-C₃N₄ in order to improve its photocatalytic activity,including element doping,semiconductor recombination,structure regulation and so on.In this paper,mesoporous carbon-graphite carbon nitride composites?meso-C/CN?with large specific surface area have been fabricated using partial hydroxymethylated dicyandiamide as precursor and gas phase silica as hard template,Then,Fe₃O₄/C-g-C₃N₄ composites were prepared by the construction of Fe₃O₄ and meso-C/CN heterojunction,which endow the material with magnetic separation properties and improve the photocatalysis of the composites.The specific research contents are as follows:?1?meso-C/CN were prepared by high temperature thermal polymerization method using partial hydroxymethylated dicyandiamide as precursor and gas phase silica as hard template,The products were characterized by Fourier Transform Infrared Spectrometer?FT-IR?,BET surface analysis,wide-angle X-ray powder diffraction?XRD?,elemental analysis.The photocatalytic activity of meso-C/CN was tested by photocatalytic degradation of methylene blue?MB?.The results show that Meso-C/CN has mesoporous structure and the introduction of C element is successful.The specific surface area of meso-C/CN is up to 117.6 m²/g,while that of pure g-C₃N₄ is 10.99 m²/g,the specific surface area is greatly improved.The photocatalytic activity of meso-C/CN is 5.6 times higher than that of pure g-C₃N₄.The photocatalysis mechanism of the material was verified by adding free radical trapping agent.The hole and hydroxyl radical were the main active groups in the photocatalysis.?2?Fe₃O₄/C-g-C₃N₄ composites?Fe/C-g-C₃N₄-x?with heterogeneous structure were prepared by coprecipitation using meso-C/CN as raw material.The products were characterized by high-resolution transmission electron microscopy,X-ray photoelectron spectroscopy?XPS?,Magnetic performance analysis,BET surface analysis,wide-angle X-ray powder diffraction.The results show that formation of heterostructures between Fe₃O₄ and C-g-C₃N₄,The specific surface area of Fe/C-g-C₃N₄-8 is 85.36 m²/g.However,photocatalytic experiments show that the photocatalytic activity of the material is higher than that of meso-C/CN,and the photocatalytic rate constant is 6.6 times that of pure g-C₃N₄,which indicates that the heterostructure promotes the separation efficiency of photogenerated electron hole pairs.The magnetic properties of the materials were tested by magnetic separation experiments,and the results showed that the materials had good magnetic properties,and the reuse performance of the materials was tested by five consecutive photocatalysis experiments,and the removal rate of the materials could reach more than 90%,The results show that the reuse performance of the material is better.