On the Electrochemical Deposition and Dissolution of Divalent Metal Ions

Abstract

The deposition of Cu(2+) and Zn(2+) from aqueous solution has been investigated by a combination of classical molecular dynamics, density functional theory, and a theory developed by the authors. For both cases, the reaction proceeds through two one-electron steps. The monovalent ions can get close to the electrode surface without losing hydration energy, while the divalent ions, which have a stronger solvation sheath, cannot. The 4s orbital of Cu interacts strongly with the sp band and more weakly with the d band of the copper surface, while the Zn 4s orbital couples only to the sp band of Zn. At the equilibrium potential for the overall reaction, the energy of the intermediate Cu(+) ion is only a little higher than that of the divalent ion, so that the first electron transfer can occur in an outer-sphere mode. In contrast, the energy of the Zn(+) ion lies too high for a simple outer-sphere reaction to be favorable; in accord with experimental data this suggests that this step is affected by anions.

Copper Electrodeposition Kinetics Measured by Alternating Current Voltammetry and the Role of Ferrous Species

“…18 Such a scheme is in agreement with the mechanism presented in introduction, with reaction 5 involving surface species, e.g. adsorbed species.…”

Modeling of electron transfer across electrochemical interfaces: State‐of‐the art and challenges for quantum and computational chemistry

“…The most rigorous way to take into account solvent effects when calculating the work term (i.e., the Potential of Mean Force, PMF) is based on MD simulations. Pinto et al have constructed three PMF in order to model the electrochemical deposition of Ag + , Zn 2+ , and Cu 2+ ions from aqueous solutions. PMF describing the interaction of ferrocene and ferrocenium with the Au(111)/room temperature ionic liquid (RTIL) interface have been reported recently by the authors …”

Influence of the NaOH Concentration on the Hydrogen Electrode Reaction Kinetics of Ni and NiCu Electrodes

“…[28] In this work, we present a kinetic study of the HOR/HER on Ni electrodes in the pH range from 12 to 14. Since the HOR/HER activity of Ni is rather low [29][30][31] due to the strong hydrogen binding to the surface, [32][33][34] it is usually enhanced either by partially oxidizing Ni surfaces [21,[35][36][37][38] or by combining Ni with other non-noble transition metals such as Mo, Cr, Co or Cu. [34,[39][40][41][42][43][44] Hence, to have a better understanding of the pH dependence, along with metallic Ni, in this work we also explore a partially oxidized Ni as well as a NiCu/C electrode.…”