Theoretical characterization of H2 adsorption on AuPt clusters

✍ Scribed by A. Cruz; E. Poulain; G. Del Angel; S. Castillo; V. Bertin

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 212 KB
• Volume: 67
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1998)67:6<399::aid-qua5>3.0.co;2-q

✦ Synopsis

Linear and triangular AuPt cluster reactions with H are studied n 2 Ž . theoretically, using ab initio multiconfiguration self-consistent field MC-SCF Ž . calculations, followed by extensive multireference configuration interaction MR-CI variational and perturbative. Both the linear dimer and the triangular trimers capture the hydrogen molecule by the Pt cluster side and by the Au cluster side. Gold has an electronic effect on the Pt activity, more important than a geometrical one, poisoning the Pt activity to dissociate H and lowering the adsorption heats. This effect is stronger in 2 the AuPt dimer, where the H capture occurs only at the molecular level, without 2 showing hydrogen bond dissociation. The trimers look more active, relaxing the H-H bond until breakage. No activation barriers are observed in all the cases considered. The hydrogen molecule is not able to cross the clusters due to the large barriers present.