Dioxygen evolution induced by visible light atlayered sensitizer/water oxidationcatalyst

Abstract

Photoelectrocatalytic water oxidation was investigated using a multilayer-modified electrode composed of a Nafion (Nf) membrane incorporating tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy) 3 ] 2+ ) sensitizer and an electrodeposited platinum black (Pt-black) adsorbing trinuclear ruthenium complex (Ru-red) ([(NH 3 ) 5 Ru(µ-O)Ru (NH 3 ) 4 (µ-O)Ru(NH 3 ) 5 ] 6+ ) as a water oxidation catalyst. In this multilayered indium tin oxide (ITO)/Nf [Ru(bpy) 3 2+ ]/Pt-black[Ru-red] system, an anodic photocurrent was generated induced by photoexcitation of [Ru(bpy) 3 ] 2+ . This anodic photocurrent was much higher than that generated without Ru-red. Dioxygen evolution was also induced by visible light at anodic applied potentials, which was ascribed to rapid transfer of positive charge from [Ru(bpy) 3 ] 3+ to Ru-red where water oxidation takes place.