title: Solvothermal synthesis and characterization of anatase TiO2 nanocrystals with ultrahigh surface area.
abstract: Phase-pure, ultrafine nanocrystalline anatase with high specific surface area (up to 250 m(2) g(-1)) was obtained upon injection of a titanium alkoxide precursor into ethanol with designed volume of water under mild solvothermal conditions (<200 degrees C, 2 h). Primary particle sizes were tuned by adjusting various reaction parameters, with the smallest grain sizes occurring at low temperatures (140-150 degrees C), low initial alkoxide concentrations, and intermediate hydrolysis ratios (r identical with[H2O]/[Ti(OR)4]=5-10). Additionally, variations in the reaction temperature result in changes in particle morphology and distribution, with high-temperature samples exhibiting bimodal distributions of small spherical and larger cubic particles that suggest grain growth via Ostwald ripening. A crystalline product with high thermal stability and specific surface area up to 5 times that of commercial nano-titania can be obtained at a relatively low temperature of 150 degrees C. The physical properties of the titania samples obtained in this study suggest they might be well suited for catalytic applications.
authors.affiliation: Chemistry Department, MS-60, Center for Biological and Environmental Nanotechnology, Rice University, Houston, TX 77005-1892, USA.
authors.forename: Rajeev K
authors.initials: RK
authors.lastname: Wahi
authors.forename: Yunping
authors.initials: Y
authors.lastname: Liu
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Falkner
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Colvin
mesh_terms: D000327:Adsorption; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry*
chemical_list: D012997:Solvents; C009495:titanium dioxide; D014025:Titanium