Alkaline-resistant titanium dioxide thin film displaying visible-light-induced superhydrophilicity initiated by interfacial electron transfer

摘要

We synthesized a three-layer-type photocatalytic structure (TiO _2/Cu(II)SiO_2/SiO_2), consisting of TiO _2 on Cu(II)-grafted SiO_2, which was deposited on a SiO_2-coated glass substrate, and investigated its visible-light absorption and hydrophilic properties. Water contact angle measurements revealed visible-light-induced superhydrophilicity at the film surface that was initiated by interfacial electron transfer (IFET) at the interface of TiO _2 and Cu(II)SiO_2. Monitoring the oxidation state of Pb2+ ions confirmed that the IFET-initiated holes diffused to the TiO_2 surface, where they likely contributed to the hydrophilic conversion. We also demonstrated that layer-structured TiO_2/Cu(II) SiO_2/SiO_2 was stable under alkaline conditions. Thus, we successfully synthesized alkaline-resistant TiO_2 that displays visible-light-induced superhydrophilicity.