Density functional theory studies on the structures and NO molecule adsorption and dissociation of Rh_mPd_n (m plus n=13) clusters

Density functional theory (DFT) studies are performed on the geometric structures, stability, electronic properties of the RhmPdn (m + n = 13) clusters. All the configurations are 13-atomic icosahedral structures, with an atom in the central site. Rh1Pd12 has I-h symmetry and relatively suitable stability and electronic properties among these clusters, with moderate stability and inter-atomic binding interaction as the representative system for the study of NO molecule adsorption and dissociation. NO molecule tends to be end-on adsorbed on Rh1Pd12 with its N atom connecting to metal atoms of the cluster, preferably at the hollow site to the top or bridge site. For the dissociation of NO as a key step in its reduction, the adsorption and dissociation of NO on Rh(1)Pd12 cluster are overall exothermic reactions from the energies of the free NO molecule and the cluster. Doping Rh in the pure cluster affects little on the adsorption energy and dissociation energy barrier but much on the relative energy (the energy reduction from the free NO molecule and cluster to the final state).