Preparation And Performance Study Of Titanium Dioxide Photocatalyst

With the energy crisis and environmental pollution becoming more and more serious,the use of clean solar energy to solve environmental pollution and energy shortage has become one of the global research hotspots.Semiconductor photocatalytic technology can convert the abundant solar energy into chemical energy,with green,no secondary pollution and energy saving advantages,thus is considered to be one of the effective way to solve the issues of energy crisis and environmental pollution.The core problem of photocatalytic technology is the development of efficient photocatalytic materials.As a kind of traditional semiconductor,TiO₂photocatalyst has become the researchers are most interested in semiconductor materials owing to the advantages of chemical stability and cheap.However,titanium dioxide is a kind of wide band gap semiconductor materials?3.2 eV?,its utilization of sunlight is very small,and the light electrons and holes can't be effectively separated,which greatly reduces the photocatalytic performance of TiO₂.In this work TiO₂ is modified by carbon doping and the construction of g-C₃N₄/TiO₂ composite material,and the effects of the morphology,structure and composition of the samples on the optical properties and photocatalytic properties of the samples are analyzed.The main results are as follows:?1?TiO₂ nanoparticles were prepared by hydrolysis method.The carbon-doping level was controlled by adding different concentration of glucose.All the synthesized samples are confirmed to anatase crystalline phase of TiO₂.However,the diffraction peak?101?of C-doped TiO₂ shifts slightly to lower angle in comparison to pure TiO₂,which indicates that carbon is doped into the lattice of TiO₂.It is found that carbon doping causes the increase of photoelectric current,indicating that it can effectively promote photogenic electron-hole pair separation and inhibit its recombination.Moreover,with appropriate carbon doping shows enhanced photocatalytic activity under UV and visible light irradiation,which can introduced defects and doping level,offer more pollutants adsorption and catalytic reaction of the active site,and effectively separate the light electronic-hole.This work provides a simple and effective method for the large-scale synthesis of high-efficiency photocatalytic materials.?2?The composite materials of TiO₂ and g-C₃N₄ were prepared by oil bath.The SEM morphology analysis shows that the sample surface is wrapped with a layer of curly layer,and the Raman peaks obviously shift,indicating the strong interaction between g-C₃N₄ with TiO₂ and the formation of TiO₂/g-C₃N₄ composites.It is found that the photocatalytic activity is greatly enhanced in the degradation of MB.The photocatalytic activity is highest,when the mass ratio of urea and TiO₂ is 1:14.The experimental results of free radical capture show that h⁺and·OH are the main active species.The enhanced mechanism of g-C₃N₄/TiO₂ composite can be attributed to ?-style mechanism.The enhanced photocatalytic activity is derived from the increase of reactive sites and the effective separation of photogenic carriers.This work provides an effective way for the realization of visible photocatalysis and improves the utilization of solar energy.