The adsorption of oxygen on bimetallic Pd3M2 clusters (M = Ag, Au, Co, Cu, Mn, Ni, Pt, and Ru) with and without alumina support by density functional theory

• Cluster alloys atomic and electronic structures. • Alloying of palladium clusters. • Adsorption of O and O2 on bi-metallic alloys. • Supported bi-metallic clusters. We performed density functional theory (DFT) calculations to systematically investigate the adsorption of atomic and molecular oxygen on the bimetallic Pd 3 M 2 clusters ( M = Ag, Au, Co, Cu, Mn, Ni, Pt, and Ru) supported on hydroxylated alumina. The interaction between the atomic and molecular oxygen with unsupported Pd 3 M 2 clusters was also computed for comparison. It was found that oxygen molecule dissociates spontaneously upon adsorption on Pd 3 Co 2 , Pd 3 Mn 2 , and Pd 3 Ru 2 for both unsupported and hydroxylated alumina-supported situations. For all other cases, the bond length of molecular oxygen is activated to a superoxo state upon adsorption. Bader charge analysis revealed that when the charge transfer to the antibonding π orbital of the oxygen molecule was greater than -1.3 electrons, the oxygen molecule dissociated spontaneously. The study of the adsorption of atomic oxygen on the hydroxylated alumina-supported clusters showed that the adsorbed oxygen atom spontaneously picks up H-atom from the substrate for all cases forming OH and representing a reverse H-spillover except for the Pd 3 Ru 2 cluster. Water molecule is formed when atomic oxygen is adsorbed on hydroxylated alumina-supported Pd 3 Mn 2 cluster due to the spontaneous pick up of two H-atoms from the substrate by the adsorbed atomic oxygen.