Underpotential Deposition of Lead on Cu(100) in the Presence of Chloride:  Ex-Situ Low-Energy Electron Diffraction, Auger Electron Spectroscopy, and Electrochemical Studies

Abstract

Electrochemical and ultrahigh vacuum measurements are presented for the underpotential deposition (UPD) of Pb on Cu(100) in the presence of chloride ions. The chemistry is very similar to that for the (111) surface studied previously by the same methods. UPD Pb forms a compact layer of fully discharged atoms having essentially the same density as that in the (100) plane of bulk Pb. The deposition appears to occur via a single process, the nucleation and growth of Pb islands, but other types of growth modes cannot be excluded. The presence of chloride ion in the electrolyte enhances the kinetics of Pb deposition in both the underpotential and overpotential regions and results in a ≈0.1 V negative shift in the mean potential for UPD versus that in chloride-free perchloric acid. This shift can be accounted for in a simple thermodynamic model for the total Cu/Pb/Cl system. The only real difference in Pb UPD on the two different Cu crystal faces was the absence of an ordered structure for the compact layer on Cu(100), versus the ordered structure observed on Cu(111). This difference appears to be related to a lower mobility of Pb adatoms due to the greater atomic corrugation of the (100) surface.

The Effect of Ionic Liquids on the Corrosion Inhibition of Copper in Acidic Chloride Solutions

“…Regarding the mechanism of the oxygen reduction reaction on copper in acidic solutions a lot of work has been done [45][46][47][48]. The cathodic polarization curve (a) may be attributed to the diffusion-controlled reduction of oxygen.…”

On the electrodeposition mechanism of Pb on copper substrate from a perchlorate solution studied by electrochemical quartz crystal microbalance

“…Pb UPD on Cu in a chloridecontaining electrolyte is accompanied by the incorporation of chloride ions into the deposition mechanism through desorption [11,12]. In addition, surface alloy formation during the formation of the UPD on copper has been observed [8].…”

“…The mechanism of lead underpotential deposition has been frequently studied using different techniques including conventional electrochemical techniques, i.e., cyclic voltammetry and chronoamperometry [9][10][11], single crystal rotating ring disk with ex-situ low-energy electron diffraction and scanning tunnelling microscopy [12][13][14] and also nanogravimetric electrochemical quartz crystal measurements [15]. Pb UPD on Cu in a chloridecontaining electrolyte is accompanied by the incorporation of chloride ions into the deposition mechanism through desorption [11,12].…”

Inhibition Effect of 1-Butyl-4-Methylpyridinium Tetrafluoroborate on the Corrosion of Copper in Phosphate Solutions

“…Regarding the mechanism the oxygen reduction reaction on copper in acidic solutions a lot of work has been carried out [61][62][63][64][65][66][67]. The cathodic global reaction in an aerated aqueous phosphate solution could be described as follows:…”