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Formation of tungsten oxide nanostructures by laser pyrolysis: stars, fibres and spheres.

Govender M, Shikwambana L, Mwakikunga BW, Sideras-Haddad E, Erasmus RM, Forbes A - Nanoscale Res Lett (2011)

Bottom Line: In this letter, the production of multi-phase WO3 and WO3-x (where x could vary between 0.1 and 0.3) nanostructures synthesized by CO2-laser pyrolysis technique at varying laser wavelengths (9.22-10.82 mm) and power densities (17-110 W/cm2) is reported.The average spherical particle sizes for the wavelength variation samples ranged between 113 and 560 nm, and the average spherical particle sizes for power density variation samples ranged between 108 and 205 nm.It was found that more concentrated starting precursors result in the growth of hierarchical structures such as stars, whereas dilute starting precursors result in the growth of simpler structures such as wires.

View Article: PubMed Central - HTML - PubMed

Affiliation: CSIR National Laser Centre, P, O, Box 395, Pretoria 0001, South Africa. BMwakikunga@csir.co.za.

ABSTRACT
In this letter, the production of multi-phase WO3 and WO3-x (where x could vary between 0.1 and 0.3) nanostructures synthesized by CO2-laser pyrolysis technique at varying laser wavelengths (9.22-10.82 mm) and power densities (17-110 W/cm2) is reported. The average spherical particle sizes for the wavelength variation samples ranged between 113 and 560 nm, and the average spherical particle sizes for power density variation samples ranged between 108 and 205 nm. Synthesis of W18O49 (= WO2.72) stars by this method is reported for the first time at a power density and wavelength of 2.2 kW/cm2 and 10.6 μm, respectively. It was found that more concentrated starting precursors result in the growth of hierarchical structures such as stars, whereas dilute starting precursors result in the growth of simpler structures such as wires.

No MeSH data available.


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A schematic of laser pyrolysis within the reaction chamber during laser-precursor interaction.
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Figure 1: A schematic of laser pyrolysis within the reaction chamber during laser-precursor interaction.

Mentions: The laser pyrolysis experimental setup was discussed in detail in [10], and a schematic description of the experiment during laser-precursor interaction is depicted in Figure 1. The laser pyrolysis method is carried out within a custom-made stainless steel chamber at atmospheric pressure. A wavelength tunable Continuous Wave CO2 laser was used in the experiments (Edinburgh Instruments, model PL6, 2 Bain Square, Kirkton Campus, Livingston, UK) and the beam was focused into the reaction chamber with a 1-m radius of curvature concave mirror which is effectively a lens with a focal length of 500 mm. For low power densities, an unfocused beam was used by replacing the concave mirror with a flat mirror. An IR-detector (Ophir-Spiricon, model PY-III-C-A, Ophir Distribution Center, Science-Based Industrial Park, Har Hotzvim, Jerusalem, Israel) was used to trace out the laser beam profile at various propagation distances from the flat or concave mirror to determine the beam properties.


Formation of tungsten oxide nanostructures by laser pyrolysis: stars, fibres and spheres.

Govender M, Shikwambana L, Mwakikunga BW, Sideras-Haddad E, Erasmus RM, Forbes A - Nanoscale Res Lett (2011)

A schematic of laser pyrolysis within the reaction chamber during laser-precursor interaction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211218&req=5

Figure 1: A schematic of laser pyrolysis within the reaction chamber during laser-precursor interaction.
Mentions: The laser pyrolysis experimental setup was discussed in detail in [10], and a schematic description of the experiment during laser-precursor interaction is depicted in Figure 1. The laser pyrolysis method is carried out within a custom-made stainless steel chamber at atmospheric pressure. A wavelength tunable Continuous Wave CO2 laser was used in the experiments (Edinburgh Instruments, model PL6, 2 Bain Square, Kirkton Campus, Livingston, UK) and the beam was focused into the reaction chamber with a 1-m radius of curvature concave mirror which is effectively a lens with a focal length of 500 mm. For low power densities, an unfocused beam was used by replacing the concave mirror with a flat mirror. An IR-detector (Ophir-Spiricon, model PY-III-C-A, Ophir Distribution Center, Science-Based Industrial Park, Har Hotzvim, Jerusalem, Israel) was used to trace out the laser beam profile at various propagation distances from the flat or concave mirror to determine the beam properties.

Bottom Line: In this letter, the production of multi-phase WO3 and WO3-x (where x could vary between 0.1 and 0.3) nanostructures synthesized by CO2-laser pyrolysis technique at varying laser wavelengths (9.22-10.82 mm) and power densities (17-110 W/cm2) is reported.The average spherical particle sizes for the wavelength variation samples ranged between 113 and 560 nm, and the average spherical particle sizes for power density variation samples ranged between 108 and 205 nm.It was found that more concentrated starting precursors result in the growth of hierarchical structures such as stars, whereas dilute starting precursors result in the growth of simpler structures such as wires.

View Article: PubMed Central - HTML - PubMed

Affiliation: CSIR National Laser Centre, P, O, Box 395, Pretoria 0001, South Africa. BMwakikunga@csir.co.za.

ABSTRACT
In this letter, the production of multi-phase WO3 and WO3-x (where x could vary between 0.1 and 0.3) nanostructures synthesized by CO2-laser pyrolysis technique at varying laser wavelengths (9.22-10.82 mm) and power densities (17-110 W/cm2) is reported. The average spherical particle sizes for the wavelength variation samples ranged between 113 and 560 nm, and the average spherical particle sizes for power density variation samples ranged between 108 and 205 nm. Synthesis of W18O49 (= WO2.72) stars by this method is reported for the first time at a power density and wavelength of 2.2 kW/cm2 and 10.6 μm, respectively. It was found that more concentrated starting precursors result in the growth of hierarchical structures such as stars, whereas dilute starting precursors result in the growth of simpler structures such as wires.

No MeSH data available.


Related in: MedlinePlus