title: Overall Water Splitting on the Transition-Metal Oxynitride Photocatalyst LaMg1/3Ta2/3O2N over a Large Portion of the Visible-Light Spectrum.
abstract: One of the main targets of studies on water splitting photocatalysts is to develop semiconductor materials with narrower bandgaps capable of overall water splitting for efficient harvesting of solar energy. A series of transition-metal oxynitrides, LaMgx Ta1-xO1+3xN2-3x(x ≥ 1/3), with a complex perovskite structure was reported as the first example of overall water splitting operable at up to 600 nm. The photocatalytic behavior of LaMg1/3Ta2/3O2N was investigated in detail in order to optimize photocatalyst preparation and water-splitting activity. Various attempts exploring photocatalyst preparation steps, that is, cocatalyst selection, coating material and method, and synthesis method for the oxide precursor, revealed photocatalyst structures necessary for achieving overall water splitting. Careful examination of photocatalyst preparation procedures likely enhanced the quality of the produced photocatalyst, leading to a more homogeneous coating quality and semiconductor particles with fewer defects. Thus, the photocatalytic activity for water splitting on LaMg1/3Ta2/3O2N was largely enhanced.
authors.affiliation: Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba-city, Ibaraki, 305-0044, Japan.
authors.forename: Chengsi
authors.initials: C
authors.lastname: Pan
authors.affiliation: Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba-city, Ibaraki, 305-0044, Japan. TAKATA.Tsuyoshi@nims.go.jp.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takata
authors.affiliation: Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba-city, Ibaraki, 305-0044, Japan. domen@chemsys.t.u-tokyo.ac.jp.|Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, 113-8656, Japan. domen@chemsys.t.u-tokyo.ac.jp.|Japan Technological Research Association of Artificial Photosynthetic, Chemical Process (ARPChem), 5-1-5 Kashiwanoha, Kashiwa-city, Chiba, 227-8589, Japan. domen@chemsys.t.u-tokyo.ac.jp.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Domen
keywords: oxynitride; perovskite phases; photocatalysis; visible light; water splitting