Density Functional Study of Molecular Hydrogen Adsorption on Small Gold–Copper Binary Clusters

• Published in: Journal of cluster science 2015-03, Vol.26 (2), p.491-503
• Main Authors: Zhao, Shuang, Tian, XinZhe, Liu, JunNa, Ren, YunLai, Ren, YunLi, Wang, JianJi
• Format: Article
• Language: English
• Subjects: Adsorption; Bimetals; Catalysis; Chemistry; Chemistry and Materials Science; Clusters; Copper; Density; Density functional theory; Energy; Gold; Hydrides; Hydrogen storage; Inorganic Chemistry; Investigations; Ionization potentials; Nanochemistry; Original Paper; Physical Chemistry
• ISSN: 1040-7278; 1572-8862
• DOI: 10.1007/s10876-015-0848-z

Density functional theory calculations were performed to investigate the molecular adsorption behaviors of hydrogen on small bimetallic Au n Cu m clusters with n  +  m  ≤ 5. H 2 prefers to bind to a copper atom in Au n Cu m H 2 complexes when both Au and Cu sites co-exist. The adsorption energies of Au n H 2 are larger than Cu n H 2 clusters with the same n and the adsorption energies of bimetallic cluster hydrides are between those of mono Au n H 2 and Cu n H 2 . The adsorption of H 2 on Au n Cu m can enhance the stability of the whole cluster. The vertical ionization potentials of the cluster hydrides generally decrease as the Cu content increases for the given cluster size. The H–H and M–H stretching frequencies (M = Au or Cu) are highly correlated to the atoms to which the adsorbate is attached. The reaction paths for H 2 dissociation on AuCu, Au 2 Cu and AuCu 2 clusters were also investigated and discussed.