Preparation Of TiO₂ Nano-composite Catalyst And Application In Photocatalytic

With the rapid development of modern industrialization,serious environmental pollution of water resources has been caused.The use of semiconductor photocatalysts for degradation and treatment of environmental pollution in water resources has become a unique method.TiO₂ semiconductors are one of the most widely studied and used photocatalysts.However,since the TiO₂ forbidden band width is more than 3.2 eV,it can only absorb wavelengths lower than 387 nm,which belongs to the ultraviolet light region and has only 5%of the total sunlight energy.At the same time,the probability of recombination of the photoelectron-hole pair generated during the photocatalytic reaction is very fast,resulting in a significant reduction in photocatalytic efficiency.In addition,the photocatalyst’s ability to adsorb pollutants is another important reason that affects the photocatalytic rate.Increasing the photocatalytic ability of the photocatalyst helps to improve the photocatalytic activity.Therefore,in view of the limitations of traditional TiO₂ photocatalysts,the preparation and photocatalytic performance of modified TiO₂ nanocomposites were investigated in this paper.The details are as follows:1.Preparation and photocatalytic performance of nonmetallic graphene/polyethyleneimine doped TiO₂ composites.Oxidation graphite（GO）was prepared by modifiedHummersmethodTitaniumdioxide/polyethylenimine/graphene（TiO₂/PEI/RGO）nanocomposite catalysts was prepared by hydrothermal method using polyethylenimine（PEI）as cross-linker and nitrogen source and titanium sulfate as titanium source.Using methylene blue（MB）as a substrate,photocatalytic function tests were performed under visible light.Studies have shown that the adsorption performance of the catalyst is significantly higher than that of pure TiO₂,the photoelectron-hole pair recombination rate is greatly reduced,and the degradation rate of MB is greatly improved.2.Synthesis and photocatalytic properties of transition metal nickel-doped TiO₂/PEI/RGO nanocomposite catalysts.Firstly,GO was prepared by modified Hummers method.Graphite oxide was used as carrier,PEI was used as cross-linker and nitrogen source,Ti（SO₄）₂ was used as precursor,and hydrothermal method was used to prepare nickel-doped TiO₂/PEI/RGO Nanocomposite Catalysts at 180°C.MB was used as degradation target to test the catalytic activity of the samples.The study showed that the activity of nickel（Ni）-doped TiO₂/PEI/RGO nanocomposite catalyst was significantly improved,the degradation rate was 98%,and it could be recycled at least10 times.3.The synthesis of platinum（Pt）-doped TiO₂/PEI/RGO composites and their photocatalytic properties.Graphene oxide was used as a carrier,PEI was used as a nitrogen source,and titanium sulfate was used as a titanium source.The Pt-doped TiO₂/PEI/RGO nanocomposite catalyst was prepared by hydrothermal method at180°C.MB was used to degrade the substrate and the catalytic activity of the sample was tested.The results showed that the activity of Pt-doped TiO₂/PEI/RGO nanocomposite catalyst was significantly improved,and the degradation rate was 98%within 28 min.By uv-vis spectrophotometer（UV-Vis）and Fourier transform infrared spectroscopy（FT-IR）,scanning electron microscope（SEM）,transmission electron microscopy（TEM）,X-ray diffraction（XRD）,Raman（Raman）,adsorption curve（BET）,such as testing method is characterized by the results.The test show that the photocatalytic electron-hole recombination probability of the modified TiO₂ is reduced,the forbidden band width is narrowed,and the photocatalytic performance is greatly improved.