TiO2-WO3 nanocomposites were prepared by colloidal processing in solvothermal conditions, with W:Ti nominal atomic ratio of
0.16 and 0.64. By exploiting the different chemical properties of the precursors, it was possible to separately nucleate TiO2
anatase nanocrystals and tiny species of W oxides. After heat-treatment at 500 °C, TiO2 nanocrystals with a size of about 8 nm
were obtained, among which WO3 monoclinic nanocrystals were dispersed, as ensured by X-ray diffraction, High-resolution
transmission electron microscopy and X-ray photoelectron spectroscopy. The resulting chemoresistive gas-sensors were tested
against acetone vapors as a sample target analyte. While pure TiO2 displayed very low response to acetone in all the operating
conditions, the addition of the WO3 component boosted the sensor response, which became comparable or even larger than pure
WO3. The analysis of the electrical properties of the nanocomposites showed that the response enhancement was not due to
doping effects, indicating a cooperative effect between the two materials oxide components.