title: Characterization of the structures of size-selected TiO2 nanoparticles using X-ray absorption spectroscopy.
abstract: To investigate the relationship between the size and structure of TiO(2) nanoparticles, three size-selected samples of TiO(2) nanoparticles were prepared via a hydrolysis method that uses Ti[OCH(CH(3))(2)](4) as the starting material. The structures of the nanoparticles were characterized using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS). Analysis of the XRD patterns and of the TEM images showed that the samples were dispersed, with an average particle size of approximately 30 nm (sample A), approximately 12 nm (sample B), and approximately 7 nm (sample C). Their X-ray absorption spectra indicate that samples A and B have an anatase structure, whereas sample C has a structure very similar to that of the TiO( 2) II phase, which generally arises only under high-pressure conditions. This difference can be attributed to size-induced radial pressure within the smaller nanoparticles, which plays an important role in the phase of TiO(2) nanoparticles in sample C.
authors.affiliation: Department of Chemistry, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Namgu, Pohang 790784, Republic of Korea.
authors.forename: Hyun Chul
authors.initials: HC
authors.lastname: Choi
authors.forename: Hyo-Jin
authors.initials: HJ
authors.lastname: Ahn
authors.forename: Young Mee
authors.initials: YM
authors.lastname: Jung
authors.forename: Min Kyu
authors.initials: MK
authors.lastname: Lee
authors.forename: Hyun Joon
authors.initials: HJ
authors.lastname: Shin
authors.forename: Seung Bin
authors.initials: SB
authors.lastname: Kim
authors.forename: Yung-Eun
authors.initials: YE
authors.lastname: Sung
mesh_terms: D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008968:Molecular Conformation; D043942:Nanotubes / Q000032:analysis* / Q000737:chemistry*; D010316:Particle Size; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D014025:Titanium / Q000032:analysis* / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D046911:Macromolecular Substances; C009495:titanium dioxide; D014025:Titanium