A new layered nanocomposite, HTaWO6/(Pt, TiO2) was synthesized using n-type semiconductor HTaWO6 as a host material. HTaWO6 and HTaWO6/TiO2 were white, while both HTaWO6/Pt and HTaWO6/(Pt, TiO2) were yellow. The yellow color might be attributed to H1-xTaWO6-x/2 formed by the photo-induced phase transformation promoted by Pt. Although HTaWO6/Pt showed absorption in visible light region (λ > 400 nm), the hydrogen evolution activity was negligibly small. On the other hand HTaWO6/(Pt, TiO2) showed excellent photocatalytic activities even under visible light irradiation. The sample containing rutile type titania such as TiO2(P-25) also showed hydrogen evolution activity, but the activity was smaller than that of HTaWO6/(Pt, TiO2). These results suggested that rutile type titania, which can be excited by visible light of wavelength less than 413 nm, played an important role in the visible light-induced photocatalytic activity. The improvement of the hydrogen evolution activity of rutile type titania by intercalating into HTaWO6/Pt may be due to the depression of the recombination of photoinduced electrons and holes by the heterogeneous electron transfer from rutile type TiO2 to HTaWO6/Pt.
- Electron transfer
- Visible light-induced photocatalytic reaction