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Title: Water-assisted synthesis of silicon oxide nanowires under supercritically hydrothermal conditions

Abstract

Large-scale amorphous silicon oxide nanowires (SiONWs) have been synthesized from silicon monoxide powder under supercritically hydrothermal conditions. The chemical bonding of amorphous SiONWs were investigated with Fourier-transform infrared (FTIR) spectrometry and near-edge x-ray absorption fine structure (NEXAFS) spectrometry. Our results show that the SiONWs are tens of microns long with a diameter from tens to hundreds of nanometers. Selected area electron diffraction (SAED) shows that the samples are amorphous. Energy dispersive x-ray spectrometry (EDX) analysis reveals that the SiONWs consist of Si and O elements in an atomic ratio approximately equal to 1:1.5. The results of FTIR and NEXAFS indicate that some OH groups are located on the surface of the SiONWs in the form of {identical_to}Si-OH. The relation between the chemical bonding and the possible growth mechanism was also discussed. During the growth process, water is an important species, which can provide H{sup +} and OH{sup -} under supercritically hydrothermal conditions. The H{sup +} and OH{sup -} block the defects of {identical_to}Si-O and {identical_to}Si, respectively, in the form of {identical_to}Si-OH and stabilize the structure. The {identical_to}Si-OH can reduce the adsorption activity of the SiONW surface which may be in favor of preventing the growth from the cross section andmore » assisting the growth along the axial direction of the SiONWs.« less

Authors:
; ; ; ; ;  [1]
  1. College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)
Publication Date:
OSTI Identifier:
20884975
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 1; Other Information: DOI: 10.1063/1.2404092; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; ABSORPTION SPECTROSCOPY; ADSORPTION; AMORPHOUS STATE; CHEMICAL ANALYSIS; CHEMICAL BONDS; CROSS SECTIONS; CRYSTAL GROWTH; ELECTRON DIFFRACTION; FINE STRUCTURE; FOURIER TRANSFORM SPECTROMETERS; HYDROGEN IONS 1 PLUS; HYDROXIDES; INFRARED SPECTRA; QUANTUM WIRES; SILICON; SILICON OXIDES; SYNTHESIS; WATER; X-RAY SPECTROSCOPY

Citation Formats

Lin, L. W., Tang, Y. H., Li, X. X., Pei, L. Z., Zhang, Y., and Guo, C.. Water-assisted synthesis of silicon oxide nanowires under supercritically hydrothermal conditions. United States: N. p., 2007. Web. doi:10.1063/1.2404092.
Lin, L. W., Tang, Y. H., Li, X. X., Pei, L. Z., Zhang, Y., & Guo, C.. Water-assisted synthesis of silicon oxide nanowires under supercritically hydrothermal conditions. United States. doi:10.1063/1.2404092.
Lin, L. W., Tang, Y. H., Li, X. X., Pei, L. Z., Zhang, Y., and Guo, C.. Mon . "Water-assisted synthesis of silicon oxide nanowires under supercritically hydrothermal conditions". United States. doi:10.1063/1.2404092.
@article{osti_20884975,
title = {Water-assisted synthesis of silicon oxide nanowires under supercritically hydrothermal conditions},
author = {Lin, L. W. and Tang, Y. H. and Li, X. X. and Pei, L. Z. and Zhang, Y. and Guo, C.},
abstractNote = {Large-scale amorphous silicon oxide nanowires (SiONWs) have been synthesized from silicon monoxide powder under supercritically hydrothermal conditions. The chemical bonding of amorphous SiONWs were investigated with Fourier-transform infrared (FTIR) spectrometry and near-edge x-ray absorption fine structure (NEXAFS) spectrometry. Our results show that the SiONWs are tens of microns long with a diameter from tens to hundreds of nanometers. Selected area electron diffraction (SAED) shows that the samples are amorphous. Energy dispersive x-ray spectrometry (EDX) analysis reveals that the SiONWs consist of Si and O elements in an atomic ratio approximately equal to 1:1.5. The results of FTIR and NEXAFS indicate that some OH groups are located on the surface of the SiONWs in the form of {identical_to}Si-OH. The relation between the chemical bonding and the possible growth mechanism was also discussed. During the growth process, water is an important species, which can provide H{sup +} and OH{sup -} under supercritically hydrothermal conditions. The H{sup +} and OH{sup -} block the defects of {identical_to}Si-O and {identical_to}Si, respectively, in the form of {identical_to}Si-OH and stabilize the structure. The {identical_to}Si-OH can reduce the adsorption activity of the SiONW surface which may be in favor of preventing the growth from the cross section and assisting the growth along the axial direction of the SiONWs.},
doi = {10.1063/1.2404092},
journal = {Journal of Applied Physics},
number = 1,
volume = 101,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Research Highlights: {yields} The increase of concentration leads to the increase of nuclei and decrease of nanorods diameter. {yields} The increase of irradiation power results in the decrease of nanorods diameter and increase their numbers. {yields} The increase of irradiation time affects more on length of nanorods.
  • With anionic surfactant LAS assisted, series of zinc cadmium sulfide semiconductor photocatalysts were synthesized by hydrothermal method. These products were characterized by X-ray diffraction (XRD), UV-Vis absorption spectra (UV-Vis) and scanning electron microscopy (FESEM). The photocatalytic activities of as-prepared samples were evaluated by photocatalytic hydrogen production from water under visible-light irradiation. The best synthesis parameters are: Composition 0.9:0.1 (Cd:Zn molar ratio), Temperature 160 deg. C, Hydrothermal Time 48 Hour, LAS Concentration 1.7 mmol/L, the maximum visible-light-catalytic hydrogen production rate is 161.25 {mu}mol/h (lambda>430 nm) which is higher than those of by coprecipitation method. The experiment results indicate that surfactant assistedmore » hydrothermal method is an effective way to get highly active CdZnS solid solution photocatalyst.« less
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  • Monodispersed aqueous ferrofluids of iron oxide nanoparticle were synthesized by hydrothermal-reduction route. They were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy and dynamic light scattering. The results showed that certain concentrations of citric acid (CA) are required to obtain only magnetic iron oxides with mean particle sizes around 8 nm. CA acts as a modulator and reducing agent in iron oxide formation which controls nanoparticle size. The XRD, magnetic and heating measurements showed that the temperature and time of hydrothermal reaction can affect the magnetic properties of obtained ferrofluids. The synthesized ferrofluids weremore » stable at pH 7. Their mean hydrodynamic size was around 80 nm with polydispersity index (PDI) of 0.158. The calculated intrinsic loss power (ILP) was 9.4 nHm{sup 2}/kg. So this clean and cheap route is an efficient way to synthesize high ILP aqueous ferrofluids applicable in magnetic hyperthermia. - Graphical abstract: Monodispersed aqueous ferrofluids of iron oxide nanoparticles were synthesized by hydrothermal-reduction method with citric acid as reductant which is an efficient way to synthesize aqueous ferrofluids applicable in magnetic hyperthermia. Highlights: Black-Right-Pointing-Pointer Aqueous iron oxide ferrofluids were synthesized by hydrothermal-reduction route. Black-Right-Pointing-Pointer Citric acid acted as reducing agent and surfactant in the route. Black-Right-Pointing-Pointer This is a facile, low energy and environmental friendly route. Black-Right-Pointing-Pointer The aqueous iron oxide ferrofluids were monodispersed and stable at pH of 7. Black-Right-Pointing-Pointer The calculated intrinsic loss power of the synthesized ferrofluids was very high.« less