Photocatalytic activity and photoinduced hydrophilicity of brookite–heteropolyacid hybrid films

After transparent hybrid films of brookite (TiO2) and 12 tungsto(VI) phosphoric acid (PW12) were prepared using layer-by-layer (LBL) processing, a comparative study of photocatalytic decomposition activity and photoinduced hydrophilicity for the films was conducted using gaseous 2-propanol (IPA) decomposition and sessile drop method. The TTP (TiO2/TiO2/PW12) film exhibited better photocatalytic activity on the decomposition of gaseous IPA than that of the TT (TiO2/TiO2) film. Moreover, the TTP film provided a higher hydrophilization rate under UV illumination, and provided better sustainability of the hydrophilicity in the dark than the TT film did. The generation of PW12− by electron transfer from TiO2 to PW12 was inferred as a key factor underpinning the overall performance of wettability conversion before and after UV illumination on this hybrid film.

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► A transparent PW12/brookite hybrid film was prepared by layer-by-layer process.
► The film exhibited better photocatalytic activity than a brookite film.
► The film also provided a higher hydrophilization rate under UV illumination.
► The electron scavenger effect of PW12 plays an important role on these results.