Methylviologen dichloride (MV) (1,1 '-dimethyl-4,4'-dipyridinium dichloride or paraquat) is widely used as an effective electron relay in the process of sacrificial water photoreduction,1 in conjunction with a variety of catalysts, such as colloidal platinum,2 hydrogenase enzyme,3 or ruthenium dioxide.4 We have recently reported that a system consisting of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+), MV, and a sacrificial electron donor, triethanolamine, in the presence of the clays, montmorillonite,5•6 789or hectorite,7 when illuminated by visible light, produces hydrogen, albeit in low yield. It has been shown that MV intercalates into the sheets of these expandable smectites6•8 with a basal spacing of 12.6 Á. Very recently, Ege et al.9 have reported the catalytic hydrogen production in a clay/Pt/poly(vinyl acetate) film containing propylviologen sulfonate. The luminescence of colloidal suspensions of Ru(bpy)32+ intercalated into these same smectites has been reported previously.10-13 Its fluorescence is

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