Structural determination of titanium-oxide nanoparticles by x-ray absorption spectroscopy

Abstract

To understand and improve the applications of titanium-oxide nanoparticles, it is extremely important to perform a detailed investigation of the surface and the interior structural properties of nanocrystalline materials, such as rutile and anatase with diameter of few nanometers. Here, x-ray absorption spectroscopy has been used to identify the local Ti environment and characterize the related electronic structure. We combine experimental results at the Ti K edge in both bulk and nanocrystal samples to determine the lattice distortion via the characteristic pre-edge features and the variation in the multiple-scattering region of the x-ray absorption near-edge structure spectra. The correlation between peak intensities and surface-to-volume ratio of nanoparticles is also discussed.

TiSi2Ox Coated N-Doped Carbon Nanotubes as Pt Catalyst Support for the Oxygen Reduction Reaction in PEMFCs

“…The characteristic feature of the Ti K edge spectra is the pre-edge weak features and the edge resonance arising from the excitation of a 1s electron into an empty bound state derived from the d and p states of Ti and O. 45,46 These pre-edge features probe the local symmetry of the Ti t 2g and E g orbitals and their behavior upon local distortion. 47 The post edge features are mainly due to the multiple scattering contribution of the ejected photoelectron from higher shell neighboring atoms.…”

“…47 The post edge features are mainly due to the multiple scattering contribution of the ejected photoelectron from higher shell neighboring atoms. 46 A number of studies have used the preedge intensity of the Ti K edge along with their positions to derive information from the Ti coordination chemistry, in compounds such as titanosilicate glass. 45,48,49 Shuji et al 49 have reported that the pre-edge features of Ti K edge XANES provide the Ti coordination number based on the plot of peak energy versus peak high.…”

“…The small differences in the peak intensity in the pre-edge region and the multiple scattering area can be attributed to the size effect, as the same trend was reported by Wu et al through comparing bulk and nanostructured TiO 2 . 46 To further characterize the composite nanostructures and investigate the effect of TiSi 2 O x coating and heat treatment on the structure of NCNTs, the nanostructures were characterized by means of Raman spectroscopy. Raman spectra of the three samples are plotted in Figure 4.…”

Nanotube diameter optimal for channeling of high-energy particle beam

“…Creating efficient channeling structures -from single crystals to epitaxial layers [2] to nanotubes -might have a significant effect onto the accelerator world. It is well known that nanotubes can be manufactured of different diameter -from a fraction of nm up to microns, of different length -from tens of microns up to millimeters, of different material -usually carbon but also others [12]. This makes nanotubes a very interesting object for channeling research.…”

Instrumental approach toward understanding nano-pollutants

“…X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure spectroscopy (EXAFS) are types of XAS in which information about atomic position of neighbors, inter-atomic distances, and bond angles can be obtained [143]. Huang et al extracted copper nano-pollutants in environmental contamination sources by room-temperature ionic liquid (RTIL) and analyzed them by XANES and EXAFS.…”