A low cost preparation of WO3 nanospheres film with improved thermal stability of gasochromic and its application in smart windows

Porous WO3 nanospheres film was successfully synthesized by employing a low-cost and facile template-assisted sol–gel method. The effects of template agent (Pluronic F127) on structure, morphology and specific surface area were systematically studied by Fourier transform infrared (FTIR), x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and N2 physisorption. It was found that F127 played a significant role in governing the morphology of WO3 sol clusters, and the optimal post-processing for 'naked' WO3 nanospheres film is acetone extraction and subsequent annealing treatment at 350 °C. As anticipated, the relative fast coloring/bleaching rates of WO3 nanospheres film are believed to be the results of porous microstructure and nanocrystalline, where provides much surface active position (166 m2 g−1) and shortens the proton diffusion distance. We believe that this unique approach to synthesize nanospheres structure may has beneficial effects on applications which also are based on insertion/extraction and diffusion abilities, such as supercapacitor, batteries and gas sensors.