Large-scale, hot-filament-assisted synthesis of tungsten oxide and related transition metal oxide nanowires
| Autor: | Ryan Thurman, Mahendra K. Sunkara, Rahel Bogale, Sreeram Vaddiraju, Trevor Powers, Jyothish Thangala, Biswapriya Deb |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Suboxide
Materials science Hot Temperature Macromolecular Substances Surface Properties Inorganic chemistry Nanowire Oxide Nucleation Molecular Conformation Tungsten Biomaterials chemistry.chemical_compound Materials Testing Transition Elements Nanotechnology General Materials Science Vapor–liquid–solid method Particle Size Titanium Nanotubes Condensation Oxides General Chemistry Tin oxide Tungsten trioxide chemistry Chemical engineering Crystallization Biotechnology |
| Zdroj: | Small (Weinheim an der Bergstrasse, Germany). 3(5) |
| ISSN: | 1613-6829 |
| Popis: | A scalable and versatile method for the large-scale synthesis of tungsten trioxide nanowires and their arrays on a variety of substrates, including amorphous quartz and fluorinated tin oxide, is reported. The synthesis involves the chemical-vapor transport of metal oxide vapor-phase species using air or oxygen flow over hot filaments onto substrates kept at a distance. The results show that the density of the nanowires can be varied from 10(6)-10(10) cm(-2) by varying the substrate temperature. The diameter of the nanowires ranges from 100-20 nm. The results also show that variations in oxygen flow and substrate temperature affect the nanowire morphology from straight to bundled to branched nanowires. A thermodynamic model is proposed to show that the condensation of WO(2) species primarily accounts for the nucleation and subsequent growth of the nanowires, which supports the hypothesis that the nucleation of nanowires occurs through condensation of suboxide WO(2) vapor-phase species. This is in contrast to the expected WO(3) vapor-phase species condensation into WO(3) solid phase for nanoparticle formation. The as-synthesized nanowires are shown to form stable dispersions compared to nanoparticles in various organic and inorganic solvents. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text