A novel oxynitride photocatalyst system for water splitting : La 2 Zn 1-x Ti 1+x (O,N) 6

The use of solar energy is of highest interest from a low environmental impact viewpoint, and nowadays the photocatalytic splitting of water under solar radiations is a challenging and promising domain of research to provide clean and renewable H 2 as an alternative energy resource [1]. Current oxide photocatalysts (TiO 2 , ZnO, SrTiO 3 , NaTaO 3 ...) are wide-gap semiconductors for which UV-light is necessary to produce electron-hole pairs by photoexcitation. Therefore, the development of visible-light-driven photocatalysts for overall water splitting is currently attracting much attention as a potential efficient utilization of solar energy. So far the (oxy)nitride approach become attractive and promising for this specific issue as a consequence of the anionic N 3- /O 2- substitution results in an increase of the covalent character which is illustrated by a shift of the absorption edge towards higher wavelength values (band gap 2 Zn 1-x Ti 1+x (O,N) 6 . It is expected that the expanded nature of the Zn 4s band improves the mobility of the photogenerated carriers thus enhancing the photocatalytic activity of the material [2]. The effect of the Zn/Ti ratio on the photocatylic behavior of the oxynitride is investigated and the performance of this new photocatalyst will be compared to the reference material LaTiO 2 N. REFERENCES 1. K. Maeda, J. Photochem. Photobiol. C: Photochem. Reviews 58-59 (2011) p. 443-446 2. J. Yin, Z. Zou, J. Ye, J. Phys. Chem. B 108 (2004) p. 12790-12794