Optimisation of the rate of hydrogen production from the tris(2,2′-bipyridyl)ruthenium(II) photosensitised reduction of methyl viologen

Abstract

Tris(2,2′-bipyridyl)ruthenium(II) photosensitised electron transfer from EDTA to methyl viologen in aqueous solution and the reduced form of the viologen was used to reduce water to H₂. The rate of formation of H₂ was dependent upon the light intensity, the pH of the solution, the type and concentration of catalyst used for the water reduction step and the concentrations of chromophore, EDTA and methyl viologen. These factors were optimised for H₂ production and alternative types of viologen were tried but none was superior to methyl viologen. The significance of these findings towards the cyclic cleavage of water into H₂ and O₂ is described briefly.