Structural investigations of TiO2–WO3–Au porous composites

• TiO2–WO3 based composites were impregnated with Au colloidal nanoparticles.
• Decrease of the anatase crystallites size of tiatania as the WO3 content increases.
• The gap energies of the TiO2–WO3 samples decrease after their impregnation with Au.
• Investigated samples have potential in photocatalytic and photovoltaic applications.

In the present study, a morpho-structural analysis of heat treated TiO2–WO3–Au aerogel composites is presented. Simultaneously, the influence of the loaded Au nanoparticles on the morphological and structural characteristics of the TiO2–WO3 aerogel is also analyzed. X-ray diffraction data (XRD) and Raman spectroscopy measurements indicated that TiO2 crystallizes mainly in anatase phase, while the WO3 structure remains amorphous. The morphological features of the samples, i.e. crystallites mean size, particle size distribution, and specific surface area of the pores, are investigated by using XRD, transmission electron microscopy (TEM), and N2 adsorption/desorption, respectively. The results indicate a decrease in size of the titania crystallites as the tungsten oxide content increases. The diffuse reflectance spectra modified by applying a Kubelka–Munk transformation reveal that the presence of gold nanoparticles improves the material’s response in the visible domain.