The synthesis of aqueous-dispersible anatase TiO2 nanoplatelets.
Aqueous well-dispersed and phase-pure anatase TiO(2) truncated octahedron nanoplatelets (NPLs) were prepared via controlled hydrolysis of titanium tetrachloride (TiCl(4)) in ethylene glycol at 240 degrees C. Two shapes, square and hexagon, were observed by microscopy, exactly corresponding to the truncated octahedron NPLs. Ethylene glycol was found to produce water in situ that reacts with TiCl(4) to produce TiO(2) and HCl-the latter promoting TiO(2) colloid peptization. TiO(2) truncated octahedron NPLs are formed under the stabilizing action of ethylene glycol thermolysis derivatives, such as aldehydes. Crystal growth of the TiO(2) NPLs was affected by the reaction temperature that determines the water production rate and HCl-assisted peptization. TGA and FT-IR results showed approximately 1.2% ethylene glycol thermolysis derivatives are attached to the surface of the TiO(2) NPLs, which prevents their agglomeration, hence making them easily dispersible in aqueous media. HR-TEM and SAED results showed that the TiO(2) NPLs are well crystallized and that the SAED patterns of the single TiO(2) NPL changes with its size and shape. XRD patterns showed that the TiO(2) NPLs are phase-pure anatase and the percentage of the [101] plane in the TiO(2) NPLs to be only 18%-a structural feature that renders the TiO(2) NPLs with enhanced UV absorption and reactivity properties.
Shan
Guo-Bin
GB
Department of Materials Engineering, McGill University, Montreal, QC, Canada. guobin.shan@mcgill.ca
Demopoulos
George P
GP
D003102:Colloids / Q000737:chemistry; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D003102:Colloids; D046911:Macromolecular Substances; D014867:Water; C009495:titanium dioxide; D014025:Titanium