A First Principles Study on Dissociation and Adsorption Processes of H2 on Pd3Ag(111) Surface

• Published in: Jpn J Appl Phys 2010-11, Vol.49 (11), p.115702-115702-4
• Main Authors: Dipojono, Hermawan Kresno, Padama, Allan Abraham B, Ozawa, Nobuki, Nakanishi, Hiroshi, Kasai, Hideaki
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.49.115702

We investigated dissociative adsorption of H 2 molecule on Pd 3 Ag(111) surface based on the constructed potential energy surfaces (PESs) from the results of first principles calculations. This study is performed to understand H 2 dissociative adsorption mechanism on Pd 3 Ag(111) surface which acts as permeable film for H 2 which is a product of biomass gasification. The PES results indicate that when the H 2 molecule approaches the Ag atom of the 1st atomic layer, the activation barriers for dissociation start to increase. The dissociation of H 2 on the surface has negligible activation barrier when the H 2 center of mass (CM) is directly above the bridge site of Pd atoms while the hydrogen atoms are directed towards the hcp and fcc hollow sites. The average local density of states (LDOS) of the d-orbital of surface Pd atoms show peak in the region around the Fermi level which is not observed from the LDOS of the Ag atom in Pd 3 Ag(111) surface. This strongly supports the results of the constructed PES for H 2 dissociative adsorption mechanism towards Pd 3 Ag(111) surface. This study will be significant for the design of hydrogen-permeable films which has applications on biomass-operated fuel cells.