Cathodic Electrodeposition of Se on Ti Electrodes

The electrodeposition of Se on Ti has been studied as a function of SeO2 concentration, presence of a surfactant (sodium n-dodecylsulphate), electrode illumination and temperature. This process is characterised by (i) a reduction peak followed by a "passive" and a "transpassive" domain in cyclic voltammetry, (ii) a slow current decay followed by an abrupt drop in chronoamperometry, and (iii) a sudden transition from a less to a more negative arrest potential in chronopotentiometry. This behaviour is specific to Ti cathodes and is not observed for other electrode materials. In the less negative potential domain, Se film growth stops at a limiting thickness which increases for deposits of better electronic conductivity. Se deposits may be grown further in the "transpassive" potential domain. The reaction mechanism in the different potential domains is presumably different.