Photogeneration of dihydrogen from water using solid hydrocarbon dispersions as support for tris(bipyridine)ruthenium(II) catalysts

Abstract

Mixtures of octadecane and tris(bipyridine)ruthenium(II) surface-active compounds were dispersed in water to give a suspension of solid particles. Upon irradiation of such dispersions with u.v.–visible light, dihydrogen gas was evolved. Dissolved dioxygen was depleted from the photolyte and carbon monoxide was detected in the gaseous products. Irradiation of deoxygenated photolytes resulted in increased yields of dihydrogen. Evidence that water is the source of the hydrogen was obtained from experiments using deuterium oxide as the dispersive medium. Irradiation of two dispersions in particular resulted in unusually high yields of dihydrogen and methane. Turnover numbers (H/Ru) in excess of 1000 have been achieved after 40 h irradiation. Attempts to duplicate these experiments are described.