The reconstructed surface gives a wide distribution of oxygen desorption energies from -0.51 eV to -3.10 eV at pH 0, U = 0 VSHE. At pH 8, U = 0 VSHE, 25.2% of the oxygen desorption is endoergic, and all the oxygen would be removed from the surface at reduction potentials more negative than -0.22 VSHE (0.26 VRHE). Instead, at pH 14, the reduction potential needs to be lower than -0.58 VSHE (0.26 VRHE) to completely remove the residual oxygen. Thus, the residual oxygen on the surface can exist under certain experimental conditions and the amount of residual oxygen could be finely tuned by controlling the reaction conditions.