The O-2 adsorptions on three low-index Pt surfaces in pure water and alkaline solution were studied using molecular dynamics (MD) and the potential of mean force methods to determine the effect of OH-coadsorption on O-2 adsorption. The MD results indicate that the adsorption configuration of O-2 molecules showed differences on various interfaces, resulting in the variation of the stability of O-2 adsorption. OH and H2O coadsorption can affect the O-2 adsorption, and represent the competitive relation of adsorption. The results indicate that the coadsorption of OH- and H2O formed a compact H-bonding network, which not only changed the adsorption configuration of O-2, but also hindered the migration of O-2 molecules from the solution to the adsorption layer. The results obtained in this study provide a theoretical basis for experimental research. (C) 2015 Elsevier B.V. All rights reserved.