Copper Deposition from Chloride-Containing Aqueous Solutions: Catalysis and the Role of the Water Structure

Abstract

The formation of complexes and the effect of a water network close to the surface on the copper deposition are investigated by means of molecular dynamics simulations. Surprisingly, the presence of chloride has a little effect on the potential of mean force for the approach of a copper ion to an electrode. In addition, the electronic transmission coefficients for Cu2+/Cu+ and [CuCl2]/[CuCl2]− redox couples are calculated in the framework of the modern theory of charge transfer in condensed media. Our results show that the metal influence on the electron transfer (ET) kinetics at the copper deposition results from two important quantities: the work terms and the electronic transmission coefficient. The ET first step proceeds in a near-adiabatic regime for both reactants. The catalytic effect of Cl? is confirmed; the ratio of the calculated rate constants for [CuCl2]/[CuCl2]− and Cu2+/Cu+ was found to be more than two orders of magnitude.