Electroreduction of Hexaamminecobalt(III) Cation on Bi ( hkl ) Electrodes from Weakly Acidified LiClO4 Solutions

Abstract

The cyclic voltammetry and rotating disk electrode methods have been used for investigation of electroreduction kinetics of the hexaamminecobalt(III) cations on the electrochemically polished Bi planes. The rate constant for the heterogeneous electroreduction reaction of the cation on the Bi(001) and planes in M aqueous base electrolyte solutions has been established and the results have been compared with the data for the Ag(110), , and Hg electrodes as well as with the data for in M solutions. In the region of zero charge potential, the value of the experimental transfer coefficient is slightly higher than 0.5 and depends on the crystallographic structure of the Bi plane. For more concentrated base electrolyte solutions, the values of apparent transfer coefficient , corrected for the double-layer effect, are practically independent of the base electrolyte concentration and slightly depend on the electrode polarization. Noticeably different values of the double-layer-corrected rate constant and for the Bi(001), , Bi(111), Hg, and Ag(110) electrodes from the data for planes have been explained by the different water and adsorption energies at the metals under discussion.