Hierarchical structured tungsten oxide nanocrystals via hydrothermal route: microstructure, formation mechanism and humidity sensing

Pang, Hua-Feng, Li, Zhi-Jie, Xiang, Xia, Fu, Yong Qing, Placido, Frank and Zu, Xiao-Tao (2013) Hierarchical structured tungsten oxide nanocrystals via hydrothermal route: microstructure, formation mechanism and humidity sensing. Applied Physics A, 112 (4). pp. 1033-1042. ISSN 0947-8396

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Abstract

Hierarchical structured tungsten oxide nanocrystals were synthesized via the hydrothermal route assisted by a capping agent of ammonium benzoate (AB). The products were characterized using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The experimental results show that the crystal microstructures could be changed from flower-shape to star-shape by changing the mole ratio of ammonium benzoate to sodium tungstate (AB/ST). The crystal phases were changed from orthorhombic WO3⋅0.33H2O to hexagonal WO3 with the increase in the concentration of AB. Based on the results from Fourier transform infrared spectroscopy and time-dependent growth analysis, a self-assembly growth mechanism has been proposed for the formation of flower, spherical, and star-netted microstructures at different mole ratios of the AB/ST. The star-netted WO3 nanocrystals were applied as a sensitive layer for humidity sensing performed using a Love-mode ZnO/36∘ Y-cut LiTaO3 surface acoustic wave device, and a stable and sensitive response to the change of relative humidity was obtained.

Item Type:	Article
Subjects:	F200 Materials Science
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Becky Skoyles
Date Deposited:	23 Mar 2015 12:12
Last Modified:	12 Oct 2019 19:08
URI:	http://nrl.northumbria.ac.uk/id/eprint/21709

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