Preparation Of Titinium Dioxide Film With High Photocatalytic Activity By Sol-Gel Process

TiO₂feature its excellent physical-chemical properties with advantages of stable,non-toxic, low price etc., and it has great application prospects in many aspects of people’slife and work. Therefore, TiO₂has opened a new area in the degradation of pollutants,disinfection and air purification with the excellent photocatalytic properties just be introducedaround people. Tetrabutyl titanate, absolute ethyl alcohol and concentrated nitric acid are usedas main titanium source, solution and catalytic agent, and use dip-coating pulling machine toprepare TiO₂thin films. The structural and optical properties of prepared TiO₂films areanalyzed by X-ray diffraction, anning electron microscopy and UV-visible spectrophotometer.It is found that the crystalline forms of TiO₂transform from anatase to rutile at annealingtemperatures between700and800℃. As the annealing temperature rises, the anatase andrutile phase showing a different quality proportional relationship, the grain size is alsochanged. The result shows that this film annealed at800℃contains31.4%anatase and68.3%rutile shows the highest light use performance and degradation ratio. There is the highestdegradation ratio just when the initial concentration of methyl orange solution is4mg/L.Acidic and alkaline environments of the methyl orange solution are beneficial to TiO₂photocatalytic membrane for degradation of methyl orange solution.Cerium nitrate used as dopant is dissolved in the quantitative of ethanol with differentmolar ratios of1%,5%,10%,15%,20%,25%. It is found that the transition temperature ofanatase to rutile phases delay after doping process. With the increasing in Ce⁴⁺dopingconcentration, anatase decrease gradually, CeO2diffraction peak appeare and graduallyenhanced. The overall degradation ratio is higher than the undoped TiO₂film, and there is thehighest degradation ratio at10%.Under the10%content of cerium nitrate, the different molar ratios of Fe is used asanother dopant with1%,5%,10%,15%,20%,25%. The phase transition temperatureincreases after doping Fe and Ce. With the increasing in Fe³⁺doping concentration, anatase isreplaced by Fe compound, and there are several morphology characteristics as decreasing anddisappearing of crystal particles. Eventually, in the view of optical character, when Fe dopingcontent is15%, there is the best light utilization and methyl orange degradation ratio.