Preparation And Photocatalytic Properties Of TiO₂-Graphene Composites

As the industrialization process forward, the contradiction of the environmental pollution is increasingly intensified, water pollution is very serious in our country. Photocatalytic oxidation technology has attracted much attention in the field of governance environment pollution for it is of safety, green environmental protection and decomposition of pollutants thoroughly characteristics. Due to its low price, nontoxic and stable chemical properties, nanometer TiO₂ has become a broad application prospect photo catalyst among many photocatalytic materials. TiO₂ semiconductor photocatalytic technology as an important technology in catalytic oxidation, therefore it becomes more and more attractive in the water pollution control. Graphene is a 2D material only with one carbon atom thickness periodically arranged by a six-member ring formed by a kind of carbon atoms in the form of sp2 hybridization. Because of its large specific surface area, good thermal and chemical stability, strong hydrophobicity, the advantages of easy for chemical modification, Graphene as a new type of carbon nanomaterials, has been widely used in the materials, catalysis, adsorption, separation, and many other fields. So that graphene and the TiO₂ composites can also show the excellent performance in the field of photocatalysis. This article main research content is as follows:（1）Using oxygen titanium sulfate bamboo charcoal, soluble phenolic resin in low molecular weight as the raw material, prepared TiO₂ and TiO₂ /graphene-like /bamboo charcoal（TiO₂-GC） composite material, through methods such as hydrothermal method and the step carbonization method, Analysist its structure by the methods of TEM（ Transmission electron microscope）, XRD（ X-ray diffraction）, PL（Photoluminescence）, UV-Vis-NIR diffuse reflectance spectrum. With methylene blue as the goal pollutant, looked at the amount of graphene in the raw material ratio, solution pH, and catalyst dosage on the properties of TiO₂- GC photocatalytic degradation effects. Experimental results show that TiO₂ prepared by the method of hydrothermal is spindle, and its particle size is from 8 to 15 nm. TiO₂ evenly distributed in the surface of GC, the compound of light electrons of titanium dioxide with holes was effectively inhibited by the composition of TiO₂.GC, that can improve the efficiency of photocatalytic reaction of the catalyst. In addition, the class of graphene content in compound, the dosage of the compound and the pH make differences to the efficiency of catalyst in the photo-degradation of methylene blue. When the pH of methylene blue solution is 8, the GC content is 6%, the catalyst inventory is 50 mg, after illuminated 90 min with ultraviolet light, photo-degradation reaction rate is 0.0509 min-1 which is three times as many as industrial photo-catalyst P25 light reaction rate 0.0170 min-1.With the agent that can eliminate free radical to explore the study of photocatalytic reaction mechanism in the photocatalytic reaction, three oxide as the main photocatalytic antioxidant are h+, ·OH and O₂-· and O₂-·is the main function（2）With oxygen titanium sulfate, flake graphite and urea as raw materials, TiO₂, C₃N₄ and TiO₂- RGO- C₃N₄ composite materials were prepared by liquid phase precipitation method. Respectively using characterization methods such as transmission electron microscopy（TEM）, X-ray diffraction（XRD）, Raman spectroscopy（Raman） and X-ray photoelectron spectroscopy（XPS） investigated the state of the structure and elements of crystal. Through the analysis methods such as XRD, TEM, the products were characterized and photocatalytic degradation of methylene blue dye performance of the composite photo-catalyst were tested under 300 w xenon lamp. Results indicate that the C₃N₄, TiO₂ and graphene composite, promotes the separation of electronic holes, accelerate the electron transfer rate, increase the utilization ratio of light and improve the photocatalytic efficiency. Graphene doping could improve the ability of adsorption of photo catalyst and conducive to the enrichment of contaminants on the surface of the semiconductor.With the agent that can eliminate free radical to explore the study of photocatalytic reaction mechanism in the photocatalytic reaction, three oxide as the main photocatalytic antioxidant are h+, ·OH and O₂-· and ·OH is the main function...