Porous WO₃ with enhanced photocatalytic and selective gas sensing properties

Pure porous WO₃ products consisting of 10-20 nm nanoparticles have been synthesized by controlling the hydrolysis of WCl₆ in ethanol solution with the assistance of polystyrene (PS) microspheres at room temperature. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area and diffuse reflectance spectroscopy. The photocatalytic and gas-sensing properties of the porous WO₃ samples were studied in detail. With large surface areas, these porous WO ₃ products exhibit both strong adsorption abilities and high degradation activities for methylene blue (MB) under visible light irradiation. And they also exhibit high sensitivity to organic gases (acetone, methanol, ethanol and formaldehyde), especially good selectivity to acetone at low concentration (0.5-5 ppm).