Journal of Applied Electrochemistry, Vol.29, No.11, 1297-1304, 1999
Electrodeposition of Zn and In onto vitreous carbon
The deposition of indium and zinc on vitreous carbon was studied by voltammetric, galvanostatic and single potentiostatic pulse techniques. The morphology and composition of deposits were analysed by SEM/EDX. The codeposition process occurs without the formation of alloys or intermetallic compounds. On the one hand under stagnant conditions or at low electrode rotation speeds, localized alkalization produced by the hydrogen evolution reaction (HER) favours deposition through an indium hydroxide layer, and deposits with the same atomic percentage of In and Zn are attained. On the other hand, under electrode rotation, preferred deposition of Zn takes place. In this case, the reduction of H+ by the In+ species, intermediate in the In3+ reduction process, diminishes the electrochemical HER on the substrate thus favouring Zn deposition. The higher nucleation rate on metallic deposits previously formed on the vitreous carbon surface is also likely.