The structures and electronic properties of Hg, HgCl, and HgCl2 adsorption on CuO(111) surface have been determined using density functional theory with the generalized gradient approximation. After optimization, a small adsorption energy of 27.4 kJ mol(-1) is found when the Hg atom on the CuO(111) surface, which infers Hg-0 is weakly physisorbed at the surface of the CuO. The adsorption configurations of HgCl, Cl-2 and HCl are the dissociative modes, but HgCl2 with the molecular modes. The mercury oxidation reaction of Hg-0 on CuO(111) surface via Cl-2 and HCl are examined and the activation barrier are 14.44 and 2.57 kJ mol(-1), respectively. It is indicated that the oxidation reaction of Hg-0 via HCl on the CuO(111) surface is likely the dominant interaction pathway. (C) 2014 Elsevier B.V. All rights reserved.