An investigation on the assembling of WO₃ particles on the matrix of silica solution

A facile way to prepare modified WO₃ structure by silica support through sol–gel method is reported. The WO₃/SiO₂ complex film was synthesized from a two steps process and dip-coating method. The films were characterized with laser particle analyzer, IR, Raman. The studies of gelation time and particle size distribution of WO₃/SiO₂ sol indicate that the silica addition could largely reduce the polycondensation of WO₃ clusters. The reaction between WO₃ and SiO₂ were further systematically investigated using IR spectra, and an insight of this reaction was illuminated. Results reveal that Si–OH in SiO₂ sols tended to crosslink with WO₃ at the corner-sharing W–O sites, by which only edge-sharing WO_x clusters could be detected. This modified the WO₃ structure was also approved by the Raman spectra, TEM and AFM images. Moreover, gas sensing properties of the WO₃/SiO₂ films were tested. The assembled WO₃ films exhibited more stable gas sensing stability than pure WO₃ films.