title: Titanium complex formation of organic ligands in titania gels.
abstract: Thin films of organic ligand-dispersing titania gels were prepared from titanium alkoxide sols containing ligand molecules by steam treatment without heating. The formation of the ligand-titanium complex and the photoinduced electron transfer process in the systems were investigated by photoelectrochemical measurements. The complex was formed between the 8-hydroxyquinoline (HQ) and titanium species, such as the titanium ion, on the titania nanoparticle surface through the oxygen and nitrogen atoms of the quinolate. A photocurrent was observed in the electrodes containing the complex due to the electron injection from the LUMO of the complex into the titania conduction band. A bidentate ligand, 2,3-dihydroxynaphthalene (DHN), formed the complex on the titania surface through dehydration between its two hydroxyl groups of DHN and two TiOH groups of the titania. The electron injection from the HOMO of DHN to the titania conduction band was observed during light irradiation. This direct electron injection was more effective than the two-step electron injection.
authors.affiliation: Department of Environmental Science and Technology, Graduate School of Science and Technology, Shinshu University , 4-17-1 Wakasato, Nagano 380-8553, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Nishikiori
authors.forename: Kenta
authors.initials: K
authors.lastname: Todoroki
authors.forename: Rudi Agus
authors.initials: RA
authors.lastname: Setiawan
authors.forename: Katsuya
authors.initials: K
authors.lastname: Teshima
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Fujii
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Satozono