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Title: Structure of nanosized materials by high-energy x-ray diffraction : study of titanate nanotubes.

Abstract

High-energy X-ray diffraction and atomic Pair Distribution Function analysis are employed to determine the atomic-scale structure of titanate nanotubes. It is found that the nanotube walls are built of layers of Ti-O{sub 6} octahedra simular to those observed in crystalline layered titanates. In the nanotubes, however, the layers are bent and not stacked in perfect registry as in the crystal.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF)
OSTI Identifier:
920567
Report Number(s):
ANL/XSD/JA-59563
Journal ID: ISSN 0044-2968; ZKKKAJ; TRN: US200818%%5
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Z. Kristallogr.; Journal Volume: 222; Journal Issue: 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; DISTRIBUTION FUNCTIONS; NANOTUBES; TITANATES; X-RAY DIFFRACTION

Citation Formats

Gateshki, M., Chen, Q., Peng, L.-M., Chupas, P., Petkov, V., Central Michigan Univ., and Peking Univ. Structure of nanosized materials by high-energy x-ray diffraction : study of titanate nanotubes.. United States: N. p., 2007. Web. doi:10.1524/zkri.2007.222.11.612.
Gateshki, M., Chen, Q., Peng, L.-M., Chupas, P., Petkov, V., Central Michigan Univ., & Peking Univ. Structure of nanosized materials by high-energy x-ray diffraction : study of titanate nanotubes.. United States. doi:10.1524/zkri.2007.222.11.612.
Gateshki, M., Chen, Q., Peng, L.-M., Chupas, P., Petkov, V., Central Michigan Univ., and Peking Univ. Mon . "Structure of nanosized materials by high-energy x-ray diffraction : study of titanate nanotubes.". United States. doi:10.1524/zkri.2007.222.11.612.
@article{osti_920567,
title = {Structure of nanosized materials by high-energy x-ray diffraction : study of titanate nanotubes.},
author = {Gateshki, M. and Chen, Q. and Peng, L.-M. and Chupas, P. and Petkov, V. and Central Michigan Univ. and Peking Univ.},
abstractNote = {High-energy X-ray diffraction and atomic Pair Distribution Function analysis are employed to determine the atomic-scale structure of titanate nanotubes. It is found that the nanotube walls are built of layers of Ti-O{sub 6} octahedra simular to those observed in crystalline layered titanates. In the nanotubes, however, the layers are bent and not stacked in perfect registry as in the crystal.},
doi = {10.1524/zkri.2007.222.11.612},
journal = {Z. Kristallogr.},
number = 2007,
volume = 222,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • We demonstrate how high-energy resonant x-ray diffraction (XRD) and differential atomic-pair-distribution function (PDF) analysis can be used to characterize the atomic ordering in materials of limited structural coherence with both excellent spatial resolution and element specificity. First we prove that this experimental approach is feasible by probing the K-absorption edge of Au({approx}81 keV) atoms in chemically ordered and disordered bulk Cu3Au alloys. The resulting Au-differential PDFs show very clearly the different ways Au atoms are known to occupy the sites of otherwise identical cubic lattices of those materials. Next we apply it to a more complex material: PtPd alloy andmore » core-shell nanosized ({approx}2-4 nm) particles by probing the K-absorption edge of Pt({approx}78 keV). The resulting Pt-differential atomic PDFs reveal how exactly the atomic ordering of catalytically active Pt atoms is affected by the nanoparticles design, thus providing a firm structural basis for understanding their properties. The work is a step forward in expanding the limits of applicability of nontraditional XRD to the rapidly growing field of materials of unusual structural complexity.« less
  • The structure of titanate nanotubes (Ti-NTs) was studied by a combination of powder X-ray diffraction (PXRD), electron diffraction and high resolution transmission electron microscopy (HRTEM). Ti-NTs are prepared by hydrothermal treatment of TiO{sub 2} powder. The structure is identified by powder X-ray diffraction as the one based on the structure of H{sub 2}Ti{sub 2}O{sub 5}·H{sub 2}O phase. The same structure is obtained by projected potential from HRTEM through-focus image series. The structure is verified by simulated PXRD pattern with the aid of the Debye formula. The validity of the model is tested by computing Fourier transformation of a single nanotubemore » which is proportional to measured electron diffraction intensities. A good agreement of this calculation with measured precession electron diffraction data is achieved. - Highlights: • Titanate nanotubes were prepared by hydrothermal method. • X-ray powder diffraction indicated their structure based on that of H{sub 2}Ti{sub 2}O{sub 5}·H{sub 2}O. • Structural model was created with the aid of high-resolution electron microscopy. • The model was verified with electron diffraction data. • X-ray powder diffraction pattern was calculated with the aid of the Debye formula.« less
  • Knowledge of the atomic-scale structure is an important prerequisite to understanding and predicting properties of materials. With bulk crystals it is routinely obtained by X-ray diffraction. With nanocrystals, however, traditional X-ray crystallography fails because of their substantially limited length of structural coherence. Here we illustrate, step by step, how a nontraditional approach involving high-energy X-ray diffraction and atomic pair distribution function analysis is applied to determine the atomic-scale structure of a typical nanocrystalline material-Fe{sub x}Pd{sub 100-x} (x = 0, 26, 28, 48) nanoparticles exhibiting useful magnetic properties.
  • An X-ray diffraction study has been carried out on boron nitride multi-walled nanotubes up to 19.1 GPa. The fit to the unit cell volumes yields a zero pressure bulk modulus K0 = 34.9 {+-} 1 GPa and its pressure derivative K{prime}{sub 0} {+-} 0.3. The compression is highly anisotropic, with the intertube-axis being close to 19 times more compressible than the a-axis. At the highest pressure the diffraction peaks were present even though they were weak and broad, which is in contrast to previous high-pressure Raman results.