Density functional study of hydrogen adsorption and dissociation on small Pdn (n = 1-7) clusters

Density functional theory has been performed to investigate the interaction of H2 and Pdn clusters (n = 1-7). The local minima configurations for different H2 molecule approach modes towards Pdn clusters are presented. Our results show that in some cases H2 is physically adsorbed around Pd atom, and in other cases H2 is dissociated to be H atoms. Except for PdH2, Pdn clusters with H atoms dissociatively adsorbed are most stable. For these most stable PdnH2 clusters (n ⩾ 2), the binding energy of hydrogen atom decreases as the number of Pd atom increases until n = 4, and when n ⩾ 4, the binding energy almost keeps constant with the H atoms bound sites changing from Pd-Pd bonds to Pd triangle planes. Besides, the adsorption of H2 on other low-lying isomers of Pdn clusters is also discussed.