Increased Water Reduction Efficiency of Polyelectrolyte-Bound Trimetallic Ru, Rh, Ru Photocatalysts in Air-Saturated Aqueous Solutions

摘要

The groundbreaking use of polyelectrolytes to increase the efficiency of supramolecular photocatalysts in solar H-2 production schemes under aqueous aerobic conditions is reported. Supramolecular photocatalysts of the architecture {(TL)(2)Ru(BL)}(2)RhX2(5+) (BL = bridging ligand, TL = terminal ligand, X = halide) demonstrate high efficiencies in deoxygenated organic solvents but do not function in air-saturated aqueous solution because of the quenching of the metal-to-ligand charge-transfer (MLCT) excited state under these conditions. The new photocatalytic system incorporates poly(4-styrenesulfonate) (PSS) into aqueous solutions containing {(bpy) 2Ru(dpp)}(2)RhCl2(5+) (bpy = 2,2'-bipyridine, dpp = 2,3-bis(2-pyridyl) pyrazine). PSS has a profound impact on the photocatalyst efficiency, increasing H-2 production over three times that of deoxygenated aqueous solutions alone. H-2 photocatalysis proceeds even under aerobic conditions for PSS-containing solutions, an exciting consequence for solar hydrogen-production research.