Chlorination of the Cu(110) Surface and Copper Nanoparticles: A Density Functional Theory Study

The interaction of atomic chlorine with the Cu(110) surface is studied using density functional theory and ab initio atomistic thermodynamics. The calculated surface free energies of different Cl/Cu(110) structures as a function of chlorine chemical potential show that under ultrahigh-vacuum conditions, the c(2 × 2)-Cl structure is the most stable for coverages up to and including 1/2 ML, whereas the (2 × 3)-Cl and (1 × 4)-Cl configurations are the most stable at 2/3 and 3/4 ML coverages, respectively. It is also shown that although there are thermodynamically stable geometries for high (1 ML) coverage of Cl, these structures are only kinetically accessible. The morphology of a copper nanostructure terminated by low-index Cu surfaces in a chlorine environment has been predicted using a Wulff construction. It is found that the (111) facets dominate at low chlorine concentration, but as the chlorine concentration is increased, the (100) planes become predominant, resulting in a cubical crystal shape.