A first-principles density functional study of chlorophenol adsorption on Cu₂O(110):CuO

First-principles density functional theory and a periodic-slab model have been employed to explore the adsorption of a two-chlorophenol molecule on a Cu₂O(110) surface containing surface Cu–O bonds, namely, the Cu₂O(110):CuO surface. The two-chlorophenol molecule is found to interact very weakly with the Cu₂O(110):CuO surface, forming several vertical and flat orientations. These weakly bound states tend to result from interaction between the phenolic hydrogen and an oxygen surface atom. The formation of a two-chlorophenoxy moiety and an isolated hydrogen on the Cu₂O(110):CuO surface from a vacuum two-chlorophenol molecule is determined to have an endothermicity of 8.2 kcal/mol (0.37 eV). The energy required to form a two-chlorophenoxy radical in the gas phase is also found to be much smaller when assisted by the Cu₂O(110):CuO surface than direct breaking of the hydroxyl bond of a free two-chlorophenol molecule. The calculated binding energy of a two-chlorophenoxy radical adsorbed directly onto the Cu₂O(110):CuO surface is −12.5 kcal/mol (0.54 eV). The Cu₂O(110):CuO and Cu(100) surfaces are found to have similar energy barriers for forming a surface-bound two-chlorophenoxy moiety from the adsorption of a two-chlorophenol molecule.