Preparation, Modification And Photocatalytic Performance Research Of Titanium Dioxide Semiconductor Photocatalyst

With the development of society,people pay more and more attention to the protection of the environment and the development of clean energy.The problem of sewage treatment has become one of the major issues for the environment today.Photocatalytic technology has a broad application prospect in the field of environmental pollution control,and has been widely concerned because of its high efficiency,energy conservation and environme nta l protection.The first generation of semiconductor photocatalyst titanium dioxide is considered to be the most promising photocatalyst due to its safety,non-toxicity,high stability,low cost,and strong oxidation ability.However,titanium dioxide has low utilization rate of sunlight and easy recombination of photo-generated carriers,resulting in low photocatalytic activity.These limitations limit its wide application in the fields of energy and environment.In this paper,titanium dioxide is modified by surfactant?polyethylene glycol?,ion doping?nitrogen doping?and morphology modifiers?potassium hydroxide?to achieve the purpose of improving its photocatalytic performance.Via single-factor experiments,exploring the effects of various process parameters on the photocatalytic performance of titanium dioxide.The optimal process parameters were confirmed,and the mechanism analysis of modified titanium dioxide was performed.The specific work is as follows:?1?polyethylene glycol-modified titanium dioxide was prepared by sol-solvother ma l method and calcination,using tetrabutyl titanate as the titanium source,polyethylene glycol?molecular weights of 4000 and 10000?as the surfactant,absolute ethanol as the solvent,glacial acetic acid as the inhibitor.Comparative analysis of polyethylene glycol?molecular weight of 4000 and 10000?modified titanium dioxide and titanium dioxide?pure titanium dioxide?without polyethylene glycol added in terms of grain size,specific surface area,morphology,photocatalytic performance and other aspects.Via single-factor experiments,the effects of the amount of polyethylene glycol with different molecular weights,reaction temperature,reaction time,calcination temperature and calcination time on the photocatalytic performance of samples were explored,and the optimal process parameters were confirmed.The polyethylene glycol-modified titanium dioxide was prepared by the optimal process,its crystal form was anatase,grain size was 7.6 nm,specific surface area was 93 m² g^-1 and it has better dispersion.The degradation of methyl orange solution under simulated visible light for120 min,the final degradation rate was 99.6%,which was 1.06 times that of pure titanium dioxide?the final degradation rate was 94%?.?2?Nitrogen-doped titanium dioxide was prepared by hydrothermal method,using pure titanium dioxide prepared by a sol-solvothermal method as a precursor,and hydrazine hydrate as a nitrogen source.Comparative analysis of nitrogen-doped titanium dioxide and pure titanium dioxide in terms of grain size,specific surface area,morphology,photocatalytic performance and other aspects.Via single-factor experiments,exploring the effects of the amount of hydrazine hydrate,hydrothermal time and hydrothermal temperature on the photocatalytic performance of samples,and the optimal process parameters were confirmed.The nitrogen-doped titanium dioxide was prepared by the optimal process,its crystal form was anatase,grain size was 10 nm,the specific surface area was 94.4 m² g^-1 and it has better dispersion.The degradation of methyl orange solution under simulated visible light for 120min,the final degradation rate was 98.9%,which was 1.05 times that of pure titanium dioxide?the final degradation rate was 94%?.?3?One-dimensional titanium dioxide nanoribbons were prepared by co-precipitatio n method combined with hydrothermal method and calcination,using titanium sulfate as the titanium source,titanium hydroxide obtained by the reaction of titanium sulfate and sodium hydroxide as the precursor,and potassium hydroxide solution as morphology regulator.Comparative analysis of titanium dioxide with and without potassium hydroxide solution in terms of grain size,specific surface area,morphology,photocatalytic performance and other aspects.Via single-factor experiments,researching the effects of potassium hydroxide concentration,hydrothermal time,and hydrothermal temperature on the photocatalytic performance of samples,and the optimal process parameters were confirmed.The titanium dioxide nanoribbons obtained by the optimal preparation process,its crystal form was anatase,length was more than 1?m,width was about 20-60 nm and its specific surface area was about78 m² g^-1.The degradation of methyl orange solution under ultraviolet light for 60 min,the final degradation rate was 98.2%,which is 1.18 times that of titanium dioxide without potassium hydroxide solution?the final degradation rate was 82.9%?.The degradation of methyl orange solution under simulated visible light for 120 min,the final degradation rate was 78.56%,which is 1.29 times that of titanium dioxide without potassium hydroxide solution?the final degradation rate was 60.77%?.