Utilization of Perovskite-Type Oxynitride La<sub>0.5</sub>Sr<sub>0.5</sub>Ta<sub>0.5</sub>Ti<sub>0.5</sub>O<sub>2</sub>N as an O<sub>2</sub>-Evolving Photocatalyst in Z-Scheme Water Splitting
Hiromu Kumagai, R. Aoyagi, Kosaku Kato, Akira Yamakata, Masato Kakihana, Hideki Kato
Abstract
The particulate Z-scheme water splitting system involving a perovskite-type oxynitride as an O2-evolving photocatalyst has been first demonstrated using La0.5Sr0.5Ta0.5Ti0.5O2N accompanied by Ru-loaded SrTiO3:Rh and [Co(bpy)3]3+/2+ (bpy = 2,2′-bipyridine) as a H2-evolving photocatalyst and an electron mediator, respectively. O2 evolution was negligible when the bare oxynitride was employed. A Pt cocatalyst deposited on La0.5Sr0.5Ta0.5Ti0.5O2N promoted the reduction of [Co(bpy)3]3+ due to capturing electrons, resulting in an enhancement of O2 evolution. It has also been discovered that the [Co(bpy)3]3+/2+ electron mediator suppresses water formation over Pt particles.