Stabilized photoanodes for water oxidation by integration of organic dyes, water oxidation catalysts, and electron-transfer mediators

Abstract

Stabilized photoanodes for light-driven water oxidation have been prepared on nanoparticle core/shell electrodes with surface-stabilized donor–acceptor chromophores, a water oxidation catalyst, and an electron-transfer mediator. For the electrode, fluorine-doped tin oxide FTOjSnO 2 /TiO 2 j-Org1-j1.1 nm Al 2 O 3 j-RuP 2+ -WOC (water oxidation catalyst) with Org1 (1-cyano-2-(4-(diphenylamino)phenyl)vinyl)phosphonic acid), the mediator RuP 2+ ([Ru(4,4-(PO 3 H 2 ) 2 -2,2-bipyridine)(2,2bipyridine) 2 ] 2+ ), and the WOC, Ru(bda)(py(CH 2 ) (3or10) P(O 3 H) 2 ) 2 (bda is 2,2-bipyridine-6,6-dicarboxylate with x = 3 or 10), solar excitation resulted in photocurrents of ∼500 μA/cm 2 and quantitative O 2 evolution at pH 4.65. Related results were obtained for other Ru(II) polypyridyl mediators. For the organic dye PP (5-(4-(dihydroxyphosphoryl) phenyl)-10,15,20-Tris(mesityl)porphyrin), solar water oxidation occurred with a driving force near 0 V.