Application of elimination voltammetry with linear scan to the study of reduction of cadmium on various electrodes
| Authors | |
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| Year of publication | 2004 |
| Type | Article in Proceedings |
| Conference | Sborník příspěvků IV. pracovní setkání fyzikálních chemiků a elektrochemiků |
| MU Faculty or unit | |
| Citation | |
| Field | Electrochemistry |
| Keywords | Elimination voltammetry with linear scan; Hg and PIGE electrodes; Cd2+/Cd reduction; cadmium deposition |
| Description | The electrochemical reduction of cadmium ions on a mercury electrode in aqueous solutions with KCl as supporting electrolyte is well known and often used for calibration of electrode systems. However, the mechanism of cadmium electrodeposition on, and stripping from mercury or other electrodes in aqueous solution with different supporting electrolytes has not been explained in details yet. In this contribution we have focused on interpretation of the Cd2+/Cd 0 process on various electrodes and in various solutions by using elimination voltammetry with linear scan (EVLS). The total current responses recorded in linear sweep voltammetry (LSV) consist of some particular currents, e.g. charging, diffusion, and kinetic currents. The EVLS enables a chosen particular current to be eliminated and unknown processes to be revealed. This approach was chosen for the study of redox processes of cadmium on a hanging mercury drop electrode (HMDE) or a paraffin-impregnated graphite electrode (PIGE). While the LSV current responses of cadmium were quite similar for both electrodes, the EVLS curves showed substantial differences. The reduction of Cd2+ was accompanied with a kinetic process. The effect of anions of the supporting electrolytes on the mechanism of the reduction process was studied. On each of the two electrodes, the elimination functions in three electrolytes (KNO3, KCl, and K2SO4) were similar. However, in each of the electrolytes, there were differences in EVLS functions between HMDE and PIGE, probably because of the different behavior of anions in the electrode double layer. |
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