One-Dimensional TiO2-B Crystals Synthesised by Hydrothermal Process and Their Antibacterial Behaviour onEscherichia coli

We have successfully synthesised one-dimensional single crystals of monoclinic phase titanium dioxide nanostructures (TiO2-B), prepared by a hydrothermal process. Morphological characterization was carried out by atomic force and scanning and transmission electron microscopy techniques. In order to study the crystalline structure, samples were calcined at 500°C in an air-filled chamber. X-ray diffraction results indicated that as-prepared samples presented diffraction patterns of hydrate hydrogen titanate and those calcined at 500°C exhibited the TiO2-B and anatase phases, confirmed by Raman spectroscopy. Scanning electron microscopy results showed that the one-dimensional nanostructures had high contrast and uniform widths for those synthesised and calcined, indicating the formation of a phase of monocrystals. Besides, a proof of the antibacterial effect was carried out of the monoclinic phase of TiO2-B onEscherichia colipure cultures, where the viability of the bacterium decreases in presence of TiO2-B nanostructures plus UV illumination. Monocrystals did not change after photocatalytic tests, suggesting a possible application as long-term antibacterial protection.

Download Full-text

Microstructural properties and formation mechanisms of GaN nanorods grown on Al2O3 (0001) substrates

Journal of Materials Research ◽

10.1557/jmr.2009.0298 ◽

2009 ◽

Vol 24 (8) ◽

pp. 2476-2482

Author(s):

Kyu H. Lee ◽

Jeong Y. Lee ◽

Y.H. Kwon ◽

Tae W. Kang ◽

Dong H. Kim ◽

...

Keyword(s):

Electron Microscopy ◽

Hydride Vapor Phase Epitaxy ◽

Formation Mechanisms ◽

Gas Mixing ◽

X Ray Diffraction ◽

One Dimensional ◽

Transmission Electron ◽

Diffraction Patterns ◽

Increasing Temperature ◽

Microscopy Images

X-ray diffraction patterns, scanning electron microscopy images, and transmission electron microscopy images showed that one-dimensional GaN nanorods with [0001]-oriented single-crystalline wurtzite structures were grown on Al2O3 (0001) substrates by hydride vapor-phase epitaxy without a catalyst. The tip morphology of the GaN nanorods became flat with increasing temperature difference between the gas mixing and the substrate zones. The gas mixing temperature significantly affected the formation of the nanorods, and the substrate temperature influenced the morphology and the strain of the GaN nanorods near the GaN/Al2O3 heterointerface. The strain and the stress existing in the GaN layer near the heterointerface were decreased with increasing growth rate. The formation mechanisms of the GaN nanorods grown on the Al2O3 (0001) substrates are described on the basis of the experimental results.

Download Full-text

Measuring Electrostatic Potential Profiles across Amorphous Intergranular Films by Electron Diffraction

Microscopy and Microanalysis ◽

10.1017/s1431927606060132 ◽

2005 ◽

Vol 12 (2) ◽

pp. 160-169 ◽

Cited By ~ 4

Author(s):

Christoph T. Koch ◽

Somnath Bhattacharyya ◽

Manfred Rühle ◽

Raphaëlle L. Satet ◽

Michael J. Hoffmann

Keyword(s):

Electron Diffraction ◽

Laboratory Frame ◽

Potential Profile ◽

Specimen Thickness ◽

One Dimensional ◽

Intergranular Films ◽

Transmission Electron ◽

Specimen Orientation ◽

Diffraction Patterns ◽

The One

Amorphous 1–2-nm-wide intergranular films in ceramics dictate many of their properties. The detailed investigation of structure and chemistry of these films pushes the limits of today's transmission electron microscopy. We report on the reconstruction of the one-dimensional potential profile across the film from an experimentally acquired tilt series of energy-filtered electron diffraction patterns. Along with the potential profile, the specimen thickness, film orientation with respect to the grain lattice and specimen surface, and the absolute specimen orientation with respect to the laboratory frame of reference are retrieved.

Download Full-text

Electrospun single-crystal MoO3 nanowires for biochemistry sensing probes

Journal of Materials Research ◽

10.1557/jmr.2006.0353 ◽

2006 ◽

Vol 21 (11) ◽

pp. 2904-2910 ◽

Cited By ~ 31

Author(s):

P. Gouma ◽

K. Kalyanasundaram ◽

A. Bishop

Keyword(s):

Electron Microscopy ◽

Single Crystal ◽

Sol Gel ◽

Electrospinning Technique ◽

One Dimensional ◽

Transmission Electron ◽

Order Of Magnitude ◽

The One ◽

One Dimensional Nanostructures ◽

Higher Sensitivity

Single-crystal MoO3 nanowires were produced using the electrospinning technique. High-resolution transmission electron microscopy revealed that the one-dimensional nanostructures are 10–50 nm in diameter, on the order of 1–2 μm in length, and have the orthorhombic MoO3 structure. The structure, crystallinity, and sensoric character of these electrostatically processed nanowires are discussed. It has been demonstrated that the nonwoven network of MoO3 nanowires exhibits an order of magnitude higher sensitivity compared with that of a sol-gel based sensor. This is promising for use of the nanowire sensors in nanomedicine.

Download Full-text

Hydrothermal Synthesis of PbS Hollow Spheres with Single Crystal-Like Electron Diffraction Patterns

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.18143 ◽

2008 ◽

Vol 8 (1) ◽

pp. 379-385

Author(s):

Pingtang Zhao ◽

Jinmin Wang ◽

Guoe Chen ◽

Zhou Xiao ◽

Jing Zhou ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Diffraction ◽

Single Crystal ◽

Sodium Citrate ◽

Near Infrared ◽

Hydrothermal Process ◽

Hollow Spheres ◽

Transmission Electron ◽

Diffraction Patterns

PbS hollow spheres were successfully prepared by a sodium citrate-assisted hydrothermal process at 120 °C for 12 h, employing lead acetate trihydrate, thiourea and sodium citrate as precursors. The diameter of PbS hollow spheres is 200–400 nm, which is composed of about 50–80 nm nanoparticles. The synthesized product was characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), Fourier transform-infrared (FT-IR) spectroscopy, ultraviolet-visible spectrometer (UV-vis) and near-infrared absorption spectrometer (NIR). The effects of the reaction conditions on morphologies of PbS structures were investigated. Star-shaped and flat PbS crystals were obtained by changing some experiment conditions. The results show that temperature, sodium citrate concentration, sulfur sources and solvent play key roles on the final morphologies formation of PbS crystals. Especially, ED result indicates that PbS hollow spheres hold single crystal-like electron diffraction patterns. And the possible formation mechanism of hollow spheres was proposed.

Download Full-text

Control of the Morphology of Molybdenum Dioxide Nanoparticles

E-Journal of Chemistry ◽

10.1155/2012/506572 ◽

2012 ◽

Vol 9 (1) ◽

pp. 233-239 ◽

Cited By ~ 3

Author(s):

R. Naouel ◽

F. Touati ◽

N. Gharbi

Keyword(s):

Electron Microscopy ◽

Thermal Analysis ◽

Scanning Electron Microscopy ◽

Hydrothermal Process ◽

X Ray Diffraction ◽

Molybdenum Dioxide ◽

One Dimensional ◽

X Ray ◽

Transmission Electron ◽

Scanning Electron

Synthesis of MoO2nanoparticles with one-dimensional (1D) and spherical morphologies in aqueous solutions, through hydrothermal process was investigated. The materials were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Infrared spectroscopy (FTIR) and thermal analysis (TG). It was found that the quantity of organic compound influenced the size and shape of the final product. The possible formation mechanism of MoO2microspheres and nanowires was also discussed. The conductivity of MoO2nanowires was explained by the presence of two protons types in the material.

Download Full-text

Nucleation of Disorder in Fe3Al Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061574 ◽

1967 ◽

Vol 25 ◽

pp. 312-313

Author(s):

P. R. Swann ◽

W. R. Duff ◽

R. M. Fisher

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Annealing Temperature ◽

Antiphase Domain ◽

Effect Of Temperature ◽

Domain Structures ◽

Transmission Electron ◽

Domain Boundaries ◽

Higher Temperature ◽

The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

Download Full-text

Effects of High-Energy Ions on Synthetic Quartz

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095972 ◽

1972 ◽

Vol 30 ◽

pp. 544-545

Author(s):

Joseph J. Comer ◽

Charles Bergeron ◽

Lester F. Lowe

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Beam ◽

High Energy ◽

Transmission Electron ◽

Kikuchi Lines ◽

High Energy Ions ◽

Diffraction Patterns ◽

Dauphiné Twinning ◽

Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

Download Full-text

Examination of Extra Electron Diffraction Spots Observed in Deuterium-Irradiated Silicon by Using Parallel Electron Beam Illumination

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136052 ◽

1990 ◽

Vol 48 (2) ◽

pp. 490-491

Author(s):

Ryuichiro Oshima ◽

Shoichiro Honda ◽

Tetsuo Tanabe

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Silicon Single Crystal ◽

Mixed Solution ◽

Parallel Beam ◽

Defect Clusters ◽

Float Zone ◽

Transmission Electron ◽

Extra Electron ◽

Diffraction Patterns

In order to examine the origin of extra diffraction spots and streaks observed in selected area diffraction patterns of deuterium irradiated silicon, systematic diffraction experiments have been carried out by using parallel beam illumination.Disc specimens 3mm in diameter and 0.5mm thick were prepared from a float zone silicon single crystal(B doped, 7kΩm), and were chemically thinned in a mixed solution of nitric acid and hydrogen fluoride to make a small hole at the center for transmission electron microscopy. The pre-thinned samples were irradiated with deuterium ions at temperatures between 300-673K at 20keV to a dose of 1022ions/m2, and induced lattice defects were examined under a JEOL 200CX electron microscope operated at 160kV.No indication of formation of amorphous was obtained in the present experiments. Figure 1 shows an example of defects induced by irradiation at 300K with a dose of 2xl021ions/m2. A large number of defect clusters are seen in the micrograph.

Download Full-text

ZnO Nanoparticles with Controllable Ce Content for Efficient Photocatalytic Degradation of MB Synthesized by the Polyol Method

Catalysts ◽

10.3390/catal11010071 ◽

2021 ◽

Vol 11 (1) ◽

pp. 71

Author(s):

Gregorio Flores-Carrasco ◽

Micaela Rodríguez-Peña ◽

Ana Urbieta ◽

Paloma Fernández ◽

María Eugenia Rabanal

Keyword(s):

Electron Microscopy ◽

Photocatalytic Degradation ◽

Doping Concentration ◽

Polyol Method ◽

Transmission Microscopy ◽

Uv Illumination ◽

Transmission Electron ◽

Optical Luminescence ◽

Pl Emission ◽

Ce Content

This paper reports on the synthesis of Ce-doped ZnO (CZO) nanoparticles (NPs) by an alternative polyol method at low temperature. The method, facile and rapid, uses acetate-based precursors, ethylene glycol as solvent, and polyvinylpyrrolidone as capping agent. The effects of the Ce-doping concentration (ranging from 0 to 8.24 atomic%) on the structural, morphological, compositional, optical, luminescence, and photocatalytic properties of the NPs were investigated by several techniques. The structural findings confirmed that the CZO NPs have a typical hexagonal wurtzite-type structure with a preferred orientation along the (101) plane. The results obtained by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) revealed that the NPs size decreased (from ~30 to ~16 nm) with an increase in the Ce-doping concentration. Energy Dispersive X-Ray Spectroscopy (EDS) and High Resolution Transmission Microscopy (HRTEM) results confirmed the incorporation of Ce ions into the ZnO lattice. Ce-doping influences the photoluminescence (PL) emission compared to that of pure ZnO. The PL emission is related to the presence of different kinds of defects, which could take part in charge transfer and/or trapping mechanisms, hence playing an essential role in the photocatalytic activity (PCA). In fact, in this work we report an enhancement of PCA as a consequence of Ce-doping. In this sense, the best results were obtained for samples doped with 3.24 atomic%, that exhibited a photocatalytic degradation efficiency close to 99% after 60 min ultraviolet (UV) illumination, thus confirming the viability of Ce-doping for environmental applications.

Download Full-text

One-step synthesis of OH-TiO 2 /TiOF 2 nanohybrids and their enhanced solar light photocatalytic performance

Royal Society Open Science ◽

10.1098/rsos.172005 ◽

2018 ◽

Vol 5 (6) ◽

pp. 172005 ◽

Cited By ~ 6

Author(s):

Chentao Hou ◽

Wenli Liu

Keyword(s):

Electron Microscopy ◽

Photocatalytic Performance ◽

Performance Enhancement ◽

Hydrothermal Process ◽

Emission Spectra ◽

Solar Light ◽

Dominant Factor ◽

Simulated Solar Light ◽

Transmission Electron ◽

Naoh Treatment

TiO 2 /TiOF 2 nanohybrids were quickly synthesized through a hydrothermal process using titanium n-butoxide (TBOT), ethanol (C 2 H 5 OH) and hydrofluoric acid as precursors. The prepared nanohybrids underwent additional NaOH treatment (OH-TiO 2 /TiOF 2 ) to enhance their photocatalytic performance. In this paper, the mechanism of NaOH affecting the pathway of transformation from TBOT (Ti precursor) to TiO 2 nanosheets was discussed. The synthesized TiO 2 /TiOF 2 and OH-TiO 2 /TiOF 2 were characterized by field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction pattern (XRD), Fourier infrared spectroscopic analysis (FT-IR), Photoluminescence (PL) emission spectra and UV–visible diffuse reflection spectra (UV–vis DRS). The photocatalytic activity and stability of synthesized samples were evaluated by degradation of methylene blue (MB) under the simulated solar light. The results showed that a larger ratio of TiO 2 to TiOF 2 in TiO 2 /TiOF 2 and OH-TiO 2 /TiOF 2 nanohybrids could allow for even higher MB conversion compared with only TiO 2 nanosheets. NaOH treatment can wash off the F ions from TiOF 2 and induce this larger ratio. The highest efficiency of MB removal was just above 90% in 1 h. Lower electron–hole pairs recombination rate is the dominant factor that induces the photocatalytic performance enhancement of TiO 2 /TiOF 2 nanohybrids. The synthesized OH-TiO 2 /TiOF 2 nanohybrids exhibit great potential in the abatement of organic pollutants.

Download Full-text