Water adsorption and dissociation on Co(0 0 0 1) have been studied using density functional theory (DFT) calculations. Present results indicate that water dimer adsorption is more stable than monomeric water on clean Co(0 0 0 1). On O-covered Co(0 0 0 1), water monomer and dimer adsorption gets stronger and O-H bond scission of H2O is much easier. Specifically, the rate-determining step for the reaction of 2H(2)O + O -> 30H + H is predicted with an activation energy of 0.967 eV on Co(0 0 0 1), considerably less than that on Pt(111). Furthermore, the presence of O-containing species (O, H2O and OH) exert different influences on O-H bond cleavage. (C) 2017 Elsevier B.V. All rights reserved.