Fabrication and characterization of WO3 flocky microspheres induced by ethanol

The novel tungsten trioxide flocky microspheres induced by ethanol were successfully obtained via a simple and convenient hydrothermal route. The as-prepared products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, BET surface area measurement and UV–Vis diffuse reflectance spectroscopy. WO3 powder prepared with volume ratio (vethanol/vwater) of 40% revealed a complete flocky microsphere structure with particle size of 3.0–4.0 μm and exhibited good photochromic property. The possible formation mechanism of the flocky microspheres was proposed and the improved photochromic properties were also investigated.