Photogeneration of hydrogen from water by a robust dye-sensitized photocathode

We report here on a photocathode with a "donor-dye-catalyst" assembly on a macro-mesoporous metal oxide for water reduction. The photoelectrocatalytic performance of the photocathode under mild conditions, with a photocurrent density of -56 μA cm^-2 and a Faradaic yield of 53%, is superior relative to other reported photocathodes with surface attached molecular catalysts. Detailed electron transfer analyses show that the successful application of this photocathode originates mainly from the slow back electron transfer following light excitation. The results also demonstrate that addition of the long-chain assembly to the macro-mesoporous electrode surface plays a fundamental role in providing sufficient catalyst for water reduction.