Coadsorption of bulky ions by surfactants. Monomolecular layers of tris(2,2'-bipyridyl)ruthenium(II) complex with sodium lauryl sulphate on glassy carbon, platinium, n-SnO2, and n-Si electrodes

Abstract

The electrochemical and photochemical behaviour of tris(2,2'-bipyridyl)ruthenium(II) complex (I) on glassy carbon, platinium, n-SnO2, and n-Si electrodes in the presence of sodium lauryl sulphate (II) was investigated. The surfactant in low concentrations induces self-association of the complex cation and its accumulation in the electrode-solution interface. At the optimum concentrations of sodium lauryl sulphate (cII ~0.6 mmol l-1) and of the complex (cI < 0.1 mmol l-1), monomolecular layers composed of I, II counterions are formed on the electrodes. The formation of the surface films does not depend on the kind of the electrode and improves the sensitivity of the voltammetric determination of I by as much as an order of magnitude. For the semiconductor electrodes, the surface films enhance the efficiency of conversion of radiant energy into electric energy. The effect under study may participate in the photosynthesis of green plants.