Electrodeposition of hard gold from acidic solution - The influence of substrates

Hard gold deposition from acidic solution on Au, Cu, Pt, Ni, and glassy carbon rotating disk electrodes was studied using linear sweep voltammetric (LSV) and chronoamperometric methods. A rotation rate-dependent peak was found on LSV curves on various substrates. Such a peak arises from an inhibition process involved in gold deposition. The mechanism and kinetics of nucleation and crystal growth in the initial stages of gold deposition on different substrates were determined. Gold deposition on Au, Cu, and Pt at more positive potentials proceeds via three-dimensional progressive nucleation and crystal growth of right-circular cones. Potential-dependent inhibition of crystal growth was also observed. A time-dependent partial inhibition of crystal growth was found for deposition on Au, Ni, and glassy carbon electrodes at more negative potentials.