Cis-oleic acid adsorption improvements by promoted platinum-nickel catalyst

S. SIMONETTI; M. MARTIRENA; S. ULACCO

Noordwijkerhout

Conferencia; Netherlands’ Catalysis and Chemistry Conference XIVth NCCC Conference; 2013

The computational study of the cis-oleic acid adsorbed, first, on a PtNi(111) surface, and then, on promoter-PtNi(111) modified surfaces (promoter = K, Mg, Co, B or Pd atoms) were performed by Yet Another Extended Huckel Molecular Orbital Package (YAeHMOP) calculations [1]. The cis-oleic acid adsorption on PtNi(111) surface shows a weak molecule-surface interaction and the C=C bond is located far away from the surface. No preferential site for C=C adsorption is detected and only the C=O adsorption is favored on the PtNi(111) surface. The adsorption properties of the PtNi(111) are then improved when promoters are added. The exposed metallic surface is then modified changing the adsorption strength of the reactant. The stability of the system increase and the C=C/surface distances are reduced when the adsorption is performed by promoters. Co promoter shows the best adsorption properties. From the electronic structure and bonding analysis, all molecular orbitals of cis-oleic acid are located at lower energy values compared to the isolated specie representing an energetic stabilization of the molecule after adsorption. The lowest C 2p orbital substantially interacts with Pt and Co s-d orbitals. The main overlap population corresponds to the C-Pt interaction. After adsorption, the strength of C=C, Pt-Pt and Pt-Co bond changes favoring the moleculesurface interaction. [1] Landrum G, Glassey W. Yet Another extended Hückel Molecular Orbital Package (YAeHMOP), Cornell University, Ithaca, NY, 2004.