Preparation And Photocatalytic Properties Of Titania Hollow Nanoboxes

As one of the most promising photocatalyst, anatase TiO2has been extensivelyinvestigated for the purpose of improving its photocatalytic performance. In this thesis,strategy for fabrication of TiO2-based photocatalyst with enhanced photocatalyticactivity was studied by forming hollow nanostructured nanoboxes using high-energyTiO2nanosheets as building blocks, which were further coupled with non-metalsemiconductor. Two parts of the thesis are shown as follows.Section1: Anatase TiO2hollow nanoboxes (TiO2-HNBs) assembly fromnanosheets with exposed {001} facets was fabricated by solvothermal treatment ofcubic TiOF2in alcohols (tert-butanol and ethanol) at180oC. It was found that phasetransformation of TiOF2to anatase TiO2begins at corners and edges of TiOF2cubes dueto in situ hydrolysis of TiOF2, where water was produced by dehydration of alcoholmolecules. With extension the reaction time, TiO2-HNBs assembly from nanosheetswith exposed high-energy {001} facets were formed due to the steady inside-outsidedissolution-recrystallization process. However, the resulted hierarchical TiO2-HNBs areunstable, which can decompose to discrete high-energy TiO2nanosheets if furtherextension the reaction time. The hierarchical TiO2-HNBs show higher photocatalyticactivity than discrete high-energy TiO2nanosheets and P25TiO2due to the uniquestructures of TiO2-HNBs.Section2: g-C3N4/TiO2-HNBs semiconductor coupling materials were prepared byone-pot solvothermal treatment of the mixed solution of cubic TiOF2and g-C3N4. It wasfound that (1) the formed hydrofluoric acid facilitated the exfoliation of g-C3N4,(2) thephotocatalytic activity of TiO2-HNBs was greatly enhanced after coupling with g-C3N4.The enhanced photocatalytic activity of g-C3N4/TiO2-HNBs semiconductor couplingmaterials can be attribute to the efficient separation of photo-generated electron-holepairs and improved light harvesting ability.Section3: Mesoporous single crystal TiO2(MSC-TiO2) was synthesized bycalcining the precursor, which was synthesized by microwave-assisted method. Thismethod is completely temple free. We found that calcination temperature is the mostimportant factor to get MSC-TiO2. The sample of T600has the highest photoactivity ofRhB degradation rate due to the mesoporous structure and broad light absorption band.