Study On Preparation And Photoestalytic Performance Of Doping TiO₂

Semiconductor photocatalysis technology has been one of the most promisingtechnologies applied to environmental cleaning to solve the problems of the currentenvironmental pollution faced by human beings. However, TiO2has a large band gapwhich making it active only in the ultraviolet range. It seriously limits the practicalapplication of the photocatalytic reaction. Therefore, how to modification thesemiconductor materials has become a research hotspot in recent years. The objectives ofthe present study were to prepare TiO2particles co-doped with boron and lanthanum(B-La-TiO2) by sol-gel method which could improve the photocatalytic activity.In Chapter I, the synthesis, application and modification methods of semiconductorphotocatalysts (mainly for the titanium dioxide) are illustrated, and the physical andchemical properties and photocatalytic mechanism of titanium dioxide are expounded.In Chapter II, the preparation processes of B-TiO2and La-TiO2have been presentated.The tetrabutyl titanate was used for precursor, and ethanol as solvent. We prepared theboron-doped TiO2(B-TiO2) and lanthanum-doped TiO2(La-TiO2) by sol-gel method.Whereafter, we discussed the photocatalytic efficiency of modified TiO2andcharacterization of these photocatalysts. At last, we evaluated the catalyst performancethrough the experiment of photocatalytic degradation of methyl orange under the visiblelight.In Chapter III, we introduced the preparation of B-La-TiO2by sol-gel method.Meanwhile, we also discussed the the possible mechanism of as-prepared B-La-TiO2.In Chapter IV, we mainly talk about the influence impacts to the photocatalyticefficiency of B-La-TiO2. Respectively, we analyzed the influence of reaction time, dryingtemperature, drying time, calcination temperature and the doping ratio of B/La. Throughthe experiment of photocatalytic degradation of methyl orange that we can ensure that thecalcination temperature and the doping ratio of B/La are the major influence factors. Whencontrolled the appropriate proportion of B/La, it could improve the photocatalyticperformance.And we determined the optimal experiment scheme for preparing the B-La-TiO2bythe orthogonal experiment: reaction time is6h, drying temperature is100℃, drying time is12h, calcination temperature is700℃and the doping ratio of B/La is1:4.We also did the validation test at the optimal scheme. The result shows that we gainedthe photocatalytic efficiency for photocatalytic degradation of methyl orange under thevisible light reached98%by using the B-La-TiO2photocatalyst.