ELECTROCATALYSTS FOR THE 4-ELECTRON REDUCTION OF DIOXYGEN BASED ON ADSORBED COBALT TETRAPYRIDYLPORPHYRIN MOLECULES LINKED BY AQUAAMINE COMPLEXES OF RUTHENIUM(II)

Prolonged exposure of graphite electrodes coated with cobalt tetrapyri dylporphyrin to solutions of fac-Ru(NH3)(5)(OH2)(3)(2+) results in the formation of stable, apparently polymeric complexes on the surface in which the porphyrins are linked by bridging Ru centers. Electrochemic al evidence in support of this assertion is presented. The coatings ob tained endow the coated electrodes with the ability of catalyze the fo ur-electron reduction of O-2 at unusually positive potentials.