title: Cobalt Oxide Nanoclusters on Rutile Titania as Bifunctional Units for Water Oxidation Catalysis and Visible Light Absorption: Understanding the Structure-Activity Relationship.
abstract: The structure of cobalt oxide (CoOx) nanoparticles dispersed on rutile TiO2(R-TiO2) was characterized by X-ray diffraction, UV-vis-NIR diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, X-ray absorption fine-structure spectroscopy, and X-ray photoelectron spectroscopy. The CoOxnanoparticles were loaded onto R-TiO2by an impregnation method from an aqueous solution containing Co(NO3)2·6H2O followed by heating in air. Modification of the R-TiO2with 2.0 wt % Co followed by heating at 423 K for 1 h resulted in the highest photocatalytic activity with good reproducibility. Structural analyses revealed that the activity of this photocatalyst depended strongly on the generation of Co3O4nanoclusters with an optimal distribution. These nanoclusters are thought to interact with the R-TiO2surface, resulting in visible light absorption and active sites for water oxidation.
authors.affiliation: Department of Chemistry, School of Science, Tokyo Institute of Technology , 2-12-1-NE-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.forename: Kazuhiko
authors.identifier: http://orcid.org/0000-0001-7245-8318
authors.initials: K
authors.lastname: Maeda
authors.affiliation: Department of Chemistry, School of Science, Tokyo Institute of Technology , 2-12-1-NE-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Ishimaki
authors.affiliation: Department of Chemistry, School of Science, Tokyo Institute of Technology , 2-12-1-NE-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Okazaki
authors.affiliation: Department of Chemistry, School of Science, Tokyo Institute of Technology , 2-12-1-NE-2 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kanazawa
authors.affiliation: Suzukakedai Materials Analysis Division, Technical Department, Tokyo Institute of Technology , 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan.
authors.forename: Daling
authors.initials: D
authors.lastname: Lu
authors.affiliation: Institute of Materials Structure Science, High Energy Accelerator Research Organization , 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Nozawa
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kato
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Kakihana
keywords: artificial photosynthesis; cobalt; photocatalyst; solar energy conversion; water splitting