Characterization of the Structures of Size-Selected TiO2 Nanoparticles Using X-Ray Absorption Spectroscopy

• Published in: Applied spectroscopy 2004-05, Vol.58 (5), p.598-602
• Main Authors: Choi, Hyun Chul, Ahn, Hyo-Jin, Jung, Young Mee, Lee, Min Kyu, Shin, Hyun Joon, Kim, Seung Bin, Sung, Yung-Eun
• Format: Article
• Language: English
• Subjects: Macromolecular Substances; Microscopy, Electron; Molecular Conformation; Nanotubes - analysis; Nanotubes - chemistry; Particle Size; Spectrometry, X-Ray Emission; Surface Properties; Titanium - analysis; Titanium - chemistry; X-Ray Diffraction
• ISSN: 0003-7028; 1943-3530
• DOI: 10.1366/000370204774103435

To investigate the relationship between the size and structure of TiO2 nanoparticles, three size-selected samples of TiO2 nanoparticles were prepared via a hydrolysis method that uses Ti[OCH(CH3)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 ∼30 nm (sample A), ∼12 nm (sample B), and ∼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 TiO2 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 TiO2 nanoparticles in sample C.