Investigation On The Hydrothermal Cryllization Process Of TiO₂ Catalyst

With the rapid development of science and technology,people’s living standards generated an unprecedented leap,then more and more of the energy consumption and pollution damage to the environment is getting worse.TiO2 has excellent electrical properties,high stability,safe non-toxic,low cost of these advantages,after modification in dye-sensitized solar cell,light degradation of pollutants,photocatalytic hydrogen production and other areas showing a broad prospect,and TiO2 provides a new way for solving energy and environmental issues.In recent years,studies for titanium dioxide has been mostly concentrated in the synthesis of the material or exhibit potential applications,and the crystallization process and its mechanism has been analyzed little.In this paper,tetrabutyl titanate as titanium source and ammonia as a mineralizing agent prepared by hydrothermal anatase titanium dioxide.By changing the initial carbon source concentration,reaction temperature,stirring rate conditions,the samples were characterized XRD,Raman,SEM,TEM,then the hydrothermal crystallization process and discovery mechanism were researched.Details are as follows:(1)In ammonia systems butyl titanate reacting anatase TiO2 process is divided into two steps:butyl titanate hydrolyzes precursor H2Ti2O5·H2O;H2Ti2O5·H2O hydrothermal crystallization was generating anatase TiO2 and anatase TiO2 crystal phase was to complete development support and reduce grain defects.(2)Changing the reaction conditions do not change the final morphology of the anatase TiO2.Anatase TiO2 was mainly into a rod shape,massive,focused on the length of 150～200nm,and width or height was about 50nm.The morphology of Agglomeration H2Ti2O5·H2O is massive particle and internal layered arrangement.H2Ti2O5·H2O length or width was about 200nm,then the thickness was about 5nm.Prolonged reaction time can reduce the H2Ti2O5·H2O aggregate level.Stirring exacerbates titanate reunion.(3)H2Ti2O5.H2O dissolves in the system to generate growth unit.In 0.16～0.32 mol/L concentration range,polymerizable group contains the number of growth units monomer increasing with concentration increasing,and the number of growth units is reacted increasing with concentration increasing in unit time.In the range of 150～180℃ the transmission rate of growth unit increases with increasing temperature.When the reaction temperature is 150℃ or 160℃,the rate of migration growth unit is approximately equal to the rate of reaction.When the reaction temperature is 170℃ or 180℃ growth unit reaction stage is controlled steps.The reaction activation energy is 89.55kJ · mol-1 by using the Arrhenius equation when the temperature is 150～160℃.The reaction activation energy is 270.26kJ · mol-1 when the temperature is 170～180℃.Stirring accelerates the process of growth units generate H2Ti2O·H2O and inhibits the process of generating its anatase TiO2.