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Time resolved Fourier Transform Electrochemical Impedance Spectroscopy (FT-EIS): Electrodeposition of copper on gold Here, we present some illustrative results of time resolved FT-EIS, where underpotential deposition (UPD) and bulk deposition (BD) of Cu on a polycrystalline Au surface are studied in an aqueous background electrolyte of 0.05 M NaClO4. The following three sets of data are presented. 1. UPD of Cu on Au, controlled by a potential step. The UPD layer is stripped with a linear voltage scan. Nyquist plots are collected at every 1 s during the experiment, and are played back at a rate of 20 frames per second. There are three plots in the animated presentation: Plot (A) shows the variation of the applied D.C. voltage (Y-axis) as a function of time (X-axis). Plot (B) shows the time dependent EIS response of a "blank" electrolyte, where no Cu2+ ions are present. Plot (C) shows the time dependent EIS response of the Cu2+-containing electrolyte. Click here to view this animation.
2. BD of Cu on Au, controlled by a potential step. Following the step, the UPD layer is deposited first. Then the BD layer is deposited on top of the UPD layer. When a Cu-stripping voltage scan is applied, the bulk layers are removed first, and then the UPD layer is removed. Nyquist plots are collected at every 1 s during the experiment, and are played back at a rate of 20 frames per second. There are three plots in the animated presentation: Plot (A) shows the variation of the applied D.C. voltage (Y-axis) as a function of time (X-axis). Plot (B) shows the time dependent EIS response of a "blank" electrolyte, where no Cu2+ ions are present. Plot (C) shows the time dependent EIS response of the Cu2+-containing electrolyte. Click here to view this animation.
3. UPD and BD (and corresponding strippings) of Cu on Au, controlled by cyclic voltammetry. The applied D.C. voltage is initially held at 0.5 V, where no deposition of Cu2+ takes place. The voltage is scanned at a rate of 0.6 mV/s from 0.5 V to -0.3 V, back to 0.5 V. Both UPD and BD processes are activated in the cathodic half-cycle (0.5 to -0.3 V), and the deposited Cu is removed througjh bulk and underpotential stripping during the anodic half cycle (-0.3 to 0.5 V0 of the scan. Nyquist plots are collected at every 1 s during the experiment, and are played back at a rate of 20 frames per second. There are three plots in the animated presentation: Plot (A) shows the variation of the applied D.C. voltage (Y-axis) as a function of time (X-axis). Plot (B) shows the time dependent EIS response of a "blank" electrolyte, where no Cu2+ ions are present. Plot (C) shows the time dependent EIS response of the Cu2+-containing electrolyte. Click here to view this animation. Note: The time resolved EIS animations presented here are best viewed with any recent version of MS Explorer. |