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 UP (TiO2/TiO2/PW12) film exhibited better photocatalytic activity on the decomposition of gaseous IPA than that of the TT (TiO2/TiO2) film. Moreover, the UP 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. (C) 2012 Elsevier B.V. All rights reserved.