Sharif Digital Repository

In this study, electronic structure, stability, and tendency to exchange electron of neutral, anionic, and cationic RhxCu4-x (x = 0-4) small clusters were investigated by density functional theory calculations. For neutral small clusters, it was found that the most stable structures of Rh4, Rh3Cu and Rh2Cu2 have distorted tetrahedral shape while the most stable structures of RhCu3 and Cu4 have quasi-planer shape. Adding charges to the clusters, caused shapes of the most stable structures undergo variations. Stabilities of the neutral, anionic, and cationic clusters decrease linearly with increasing the copper content. In addition, calculated chemical harnesses indicated that the small... 

In this study, rhodium-copper alloys of different compositions are electrodeposited on graphite electrode from aqueous solutions. The bulk compositions of these alloys are determined using energy dispersive X-ray analysis and surface morphologies are investigated by scanning electron microscopy. The catalytic performance of these alloys in oxygen reduction reaction (ORR) in alkaline media is investigated by linear sweep voltammetry on rotating disk electrode assembly. The number of electrons transferred per O 2 molecule (n) obtained at different potentials is four indicating full reduction of oxygen to hydroxide ion. It is shown that Rh-Cu alloys are better electrocatalysts than Rh with...