Y 2 Ta 2 O 5 N 2 is presented as a novel photocatalyst with high activity for water splitting under visible-light irradiation in the presence of appropriate sacrificial reagents; the activity for reduction to H 2 is increased by the incorporation of Pt or Ru as a co-catalyst, with a significant increase in production efficiency when both Pt and Ru are present.Photocatalytic splitting of water using solar energy is a challenging and interesting topic of research with the potential to provide clean and renewable H 2 as an energy resource. To date, many mixedmetal oxides such as K 2 La 2 Ti 3 O 10 , 1 NaTaO 3 , 2 and LnTaO 4 (Ln = La, Pr, Ce, Nd, Sm) 3 have been studied for water splitting as a means of producing both H 2 and O 2 , as such oxides have excellent stability and high activity. However, these catalysts are only active under ultraviolet (UV) light, which accounts for only a small fraction (5%) of the solar spectrum at the earth's surface. Therefore, the development of visible-light responsive photocatalysts for overall water splitting is currently attracting much attention as a potentially efficient utilization of solar energy. [4][5][6] Considerable effort has been made to extend the absorption edge of semiconductors with wide bandgaps into the visible-light region. 7,8 The incorporation of non-metal atoms (C, N, F, P and S) into metal-oxide lattices is one way to narrow the bandgap of the parent oxide because of their p states mixing with O 2p states. 9-11 A number of non-oxide photocatalysts have recently been reported to be promising candidates for overall water splitting under visiblelight irradiation. 6,12,13 Oxynitrides such as TaON and LaTiO 2 N have been shown to exhibit absorption in the visible region and stable photocatalytic activity for water reduction and oxidation using appropriate sacrificial reagents. However, the range of oxynitride photocatalysts synthesized to date remains limited. Although platinum is already generally considered to be the best metal promoter for H 2 production from water due to its low overpotential, it has been recently shown to exhibit remarkably enhanced efficiency for H 2 evolution under visible light when Ru was deposited on TaON. 14 This increased efficiency has been attributed to improved contact between the TaON and Ru. However, the simultaneous use of Pt and Ru as promoters of photocatalytic water reduction has yet to be reported.This communication reports Y 2 Ta 2 O 5 N 2 as a novel visible lightdriven photocatalyst with high activity for oxidation of water in the presence of a sacrificial electron acceptor (Ag 1 ). This catalyst also reduces water to H 2 in the presence of a sacrificial electron donor (ethanol) and Pt or Ru as a co-catalyst, with a significant enhancement of H 2 production efficiency in the presence of both Pt and Ru. The photocatalytic reaction was carried out in a closed gas circulation and evacuation system under a 300 W Xe lamp equipped with a cut-off filter (l w 420 nm). Photocatalytic water reduction and oxidation were performed us...

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A novel and reversible single-material solvent-sensitive actuator was developed from poly(ionic liquid) inverse opals based on a gradient wetting/dewetting process combining the strong hydrogen bonding interaction between the solvent and polymer. This study will provide an important insight for the design and fabrication of novel-type solvent-actuator materials.