Adsorption of tetraethylammonium ions on Cd(0 0 0 1) single crystal plane from solutions in ethanol

The adsorption of tetraethylammonium (TEA+) ions on the basal (0 0 0 1) plane of the cadmium single crystal from solutions in ethanol has been investigated by impedance measurement method. The experimental data were obtained in 0.02 M mixed-electrolyte solutions and the calculations performed with electrode potential as the independent electrical variable. The Gibbs energy of adsorption of TEA+ ions has been calculated using the simple virial adsorption isotherm and it was found that the adsorption of TEA+ cations is weaker than the adsorption of halide anions. The electrosorption valency evaluated has a nearly constant value in the potential region studied. It was concluded that the formed effective surface dipole is significantly screened by the solvent molecules and the metal electron gas. Comparing the adsorption characteristics with the parameters obtained for bismuth single crystal electrodes, it was found that the Gibbs adsorption energy on uncharged electrode surface is close for these metals. The results obtained indicate that only weak interaction between TEA+ ions and cadmium surface takes place and there is no remarkable partial charge transfer from the adsorbed ions to the Cd(0 0 0 1) surface atoms.