Hydrothermal synthesis, characterization of h-WO3 nanowires and gas sensing of thin film sensor based on this powder

摘要

The monodisperse hexagonal WO3 (h-WO3) nanowires were synthesized using hydrothermal treatment through the acidification of Na2WO4 center dot 2H(2)O by addition of K2SO4 and Na2SO4. The obtained products were characterized using X-ray powder diffraction, field emission scanning electron microscopy and transmission electron microscopy. It showed a high crystallinity and good dispersity of nanowire structure with the exposure of < 200 > crystal facets. Based on h-WO3 products, thin film sensors were prepared. The gas-sensing properties to various concentrations (10, 20, 50, 100, and 200 ppm) of ethanol and formaldehyde were investigated. The h-WO3 nanowires exhibited high responses to both ethanol and formaldehyde gas. The sensor exhibited remarkably good response and fast response/recovery time, which were as short as 6-8 s. A possible reason for the influence of oxide structure on the sensing properties of thin film sensors is proposed. This work shows great potential for the preparation of 1D h-WO3 nanostructures and their application in the detection of toxic gases. (C) 2014 Elsevier B.V. All rights reserved.