Zur kinetik der metallionenadsorption: II. Galvanostatische einschaltmessungen an silber-, bleiund thalliumadsorbaten auf goldelektroden

The kinetics of the metal ion adsorption of Ag⁺, Tl⁺ and Pb²⁺ on polycrystalline and (111) orientated monocycrystalline gold electrodes were investigated using a low-level short-time polarization technique. In the present case the systems were potentiostatically prepolarized under steady state equilibrium conditions. The perturbation was realized by galvanostatic square pulses. The observed overpotential—time transients were analyzed by polynomial curve fitting. The results can be interpreted in terms of the developed polarization model 1]: (1) the process of metal ion adsorption is not reversible; (2) the hindrance is caused by charge transfer and can also be influenced by surface diffusion of the adsorbed metal ion species. In the case of Ag⁺ and Pb²⁺ the calculated mean values of the exchange current densities of the sorption processes are lower than the exchange current densities of the corresponding metal ion electrodes and they do not depend markedly on the potential. The data obtained are discussed.