Generation of anodic and cathodic currents based on photoexcited tris(2,2′-bipyrazine)ruthenium(II) in aqueous solutions
Abstract
Anodic and cathodic currents have been induced at an indium–tin oxide electrode by irradiation of aqueous solutions of tris(2,2′-bipyrazine)ruthenium(II)[Ru(bipyz)3]2+ containing ethylene-diaminetetraacetic acid (H4edta) and S2O82–, respectively. The anodic photocurrent is ascribed to reductive quenching of the photoexcited species [*Ru(bipyz)3]2+ due to edta, as with C2O42–. On the other hand, the cathodic photocurrent is explained in terms of the oxidative quenching of [*Ru(bipyz)3]2+ by S2O82–. A theoretical analysis is developed to account for the dependences of the photocurrents on applied potential, concentrations of [Ru(bipyz)3]2+, edta and S2O82–, pH and light intensity.