Electric double layer structure and adsorption of cyclohexanol on single crystal cadmium, antimony and bismuth electrodes

The electric double layer structure in aqueous and non-aqueous surface inactive electrolyte solutions and the adsorption of cyclohexanol on the electrochemically polished Sb, Bi and Cd electrodes were studied by using cyclic voltammetry, impedance and chronocoulometry. The limits of ideal polarizability, the potentials of zero charge and the values of capacity of inner layer were established. As found, the differences between the zero charge potential for various planes depend on the chemical nature and crystallographic structure of the electrode surface, as well as on the chemical nature of the solvent studied. The inner layer capacity at negative surface charges depends on the crystallographic orientation of the single crystal planes and on the electronic properties of the electrode metal. The inner layer capacity increases in the sequence of metals Sb < Bi < Hg < Cd < Zn, as the hydrophility of electrodes increases and as the contribution of metal phase decreases. The values of capacity of metal phase and the effective thickness of the thin metal surface layer were calculated by using various theoretical approximations. The effective thickness of the thin layer of metal surface increases in the sequence of metals Ga < Zn < Ca < Hg < Bi < Sb as the metallic properties of electrodes decrease. The adsorption parameters of cyclohexanol were established by using Frumkin-Damaskin adsorption theory. It was found that the adsorption characteristics depend on the chemical nature and crystallographic structure of electrode surface. The adsorption activity of cyclohexanol increases in sequence of metals Zn < Cd < Bi < Hg < Sb as the adsorption energy of solvent decreases. Copyright (C) 1996 Elsevier Science Ltd.