Polymer Chromophore-Catalyst Assembly for Solar Fuel Generation

A polystyrene-based chromophore-catalyst assembly (poly- 2 ) has been synthesized and assembled at a mesoporous metal oxide photoanode. The assembly contains water oxidation catalyst centers based on [Ru(trpy) (phenq)] 2+ (Ru-Cat) and [Ru(bpy) 3 ] 2+ derivatives (Ru-C) as chromophores (trpy= 2,2′;6,2″- terpyridine, phenq = 2-(quinol-8′-yl)-1,10-phenanthroline and bpy = 2,2′-bipyridine). The photophysical and electrochemical properties of the polychromophore-oxidation catalyst assembly were investigated in solution and at the surface of mesoporous metal oxide films. The layer-by-layer (LbL) method was utilized to construct multilayer films with cationic poly- 2 and anionic poly(acrylic acid) (PAA) for light-driven photochemical oxidations. Photocurrent measurements of (PAA/poly- 2 ) 10 LbL films on mesoporous TiO 2 demonstrate light-driven oxidation of phenol and benzyl alcohol in aqueous solution. Interestingly, illumination of (PAA/poly- 2 ) 5 LbL films on a fluorine doped SnO 2 /TiO 2 core/shell photoanode in aqueous solution gives rise to an initial photocurrent (∼18.5 μA·cm –2 ) that is in part ascribed to light driven water oxidation.