First-Principles Study of Chlorine Adsorption on Clean Aluminum Surface

Using density functional theory (DFT) we investigated the adsorption of chlorine atom on aluminum surface in the orientations, (100), (110), and (111). The structural and thermodynamic properties of chlorine atoms adsorbed on the Al (100), Al (110), and Al (111) surface for chlorine coverages of 1/9, 1/4, 1/3, 1/2, 3/4, and 1 monolayer (ML) are calculated. The largest bond strength is observed for a top, fcc, and hcp mixed structure at 3/4 ML coverage on Al (111). Adsorption free energy analysis reveals that the chlorine coverage of 3/4 ML of Al (111) is the most thermodynamically stable over the widest range of chlorine chemical potential and 1 ML of Al (111) is thermodynamically unstable, whereas various chlorine coverages of Al (100) and Al (110) take stable phase for a range of chlorine chemical potential.