Effect of Chlorine on Copper Electrodissolution

Abstract

A computational study on the role of adsorbed Cl ions on copper dissolution is presented. Extensive grand canonical Monte Carlo (GCMC) calculations using reactive force-field (ReaxFF) are used to check the formation chlorine (Cl) adlayer structures on Cu (100) surface as a function of the chemical potential (µ). From experimental studies conducted by other researchers it has been observed that Cl adlattice on Cu in c(2X2) at maximum coverage. We observe that at low µ, Cl adlayer is disordered and moves to ordered c(2X2) structure at high µ. The binding energy of Cl, oxygen (O), hydroxide (OH-) and H2O on Cu at different sites is calculated and compared with Density-functional theory (DFT) values. Metal surface is often highly uneven and rough during electrodissolution process. Therefore, we also discuss the adsorption isotherm, disorder-order transformation, and preferential adsorption sites for rough surfaces. Specific anion adsorption (SAA) of Cl involves partial charge transfer to Cu substrate and these effect the type of bond and bond strength which is also briefly discussed. The electrodissolution of Cu in the presence of Cl is modelled using kinetic Monte Carlo simulation to obtain the polarization curve.Keywords: Adsorbed chlorine, electrodissolution, grand canonical monte carlo, molecular dynamics, ReaxFF, kinetic monte carlo.