Chemisorbed atomic oxygen inducing Pd segregation in PdAu(1Â 1Â 1) alloy: Energetic and electronic DFT analysis

► The surface configuration of PdAu bimetallic catalyst seems to change during gas exposure. ► Under vacuum conditions Pd tends to migrate into the bulk. ► In the presence of adsorbed oxygen, palladium segregation is favoured. ► Pd segregation is found to be oxygen-coverage dependent.