Theoretical study of H adsorption on FeNi(111) surface

LANZ. C; J.M. MARCHETTI; G. BRIZUELA; SIMONETTI, S.

Málaga

Congreso; The Energy & Materials Research Conference; 2012

Iron promoted nickel based catalyst has been developed for high yield hydrogen generation through ethanol reforming. The reaction results show a remarkable improved durability in catalytic activity as well as selectivity to hydrogen. The adsorption of H on FeNi(111) has been analyzed at theoretical level by tight binding calculations. Different sites on the surface were selected in order to establish the preferential H adsorption location and the optimum H-surface distance. The two most stable sites for H on FeNi(111) are the top Fe and the Fe-Fe bridge.  We found that the minimum energy site corresponds to the H bonding on top Fe. Fe-H bond is formed on the FeNi(111) surface and the interaction is mainly due to the overlaps between the H s orbital with the pz, s, dz2 and py Fe orbitals. On the other hand, when the H is located on the Fe-Fe bridge site, the Fe-H interaction is formed with mainly participation of pz, py, s and dyz Fe orbitals. In general, after H adsorption, the neighbouring Fe-Fe bonds are weakening while Fe-Ni and Ni-Ni bonds are slightly affected. The Ni-H interaction is not evidence on the FeNi(111) surface.