In this study, SnO₂ nanowires (NWs) were synthesized by two different thermal evaporation processes and hierarchical SnO₂ nanostructures were prepared through a combination of the two processes without reseeding of Au catalyst. Field emission scanning electron microscopy studies showed that the shape of the core NWs become distorted and attached to large quantities of quasi-one-dimensional nanostructures, mostly NWs and nanobelts. The crystal structure of these as-prepared hierarchical SnO₂ nanostructures was identified to coincide to the normal rutile structure. Photoluminescence properties are similar among the samples with a strong peak emission band centered at 620 nm that is attributed to a defect-state-related emission. The gas sensing performance of SnO₂ NWs and their hierarchical nanostructures were simultaneously investigated by testing with liquefied petroleum gas and NH₃ gas at different concentrations and operating temperatures. Results reveal that hierarchical SnO₂ nanostructures have enhanced gas sensing performance in comparison with SnO ₂ NWs materials. The gas sensing mechanism of SnO₂ hierarchical nanostructures was also discussed. Results indicate that hierarchically porous SnO₂ architectures are highly promising for gas sensor applications. © 2010 Published by Elsevier B.V.

Thong L.V., Loan L.T.N., Van Hieu N.

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Từ khóa : AU catalysts; Comparative studies; Field emission scanning electron microscopy; Gas sensing; Gas sensing mechanism; Gas sensors; Hierarchical; Hierarchical Nanostructures; Hierarchical SnO; Operating temperature; Peak emissions; Photoluminescence properties; Quasi-one-dimensional; Rutile structure; Thermal evaporation process; Chemical detection; Chemical sensors; Crystal structure; Field emission; Field emission microscopes; Gas detectors; Gas industry; Gas sensing electrodes; Gases; Liquefied petroleum gas; Nanowires; Oxide minerals; Scanning electron microscopy; Thermal evaporation; Tin; Tin oxides; Titanium compounds; Nanobelts