CO adsorption on hydrogen saturated Ru(0001)

The interaction of CO with the Ru(0001)(1 x 1)H surface has been studied by density functional theory (DFT) periodic calculations and molecular beam techniques. The hydrogen (1 x 1) phase induces an activation barrier for CO adsorption with a minimum barrier height of 25 kJ mol(-1). The barrier originates from the initial repulsive interaction between the CO-4 sigma and the Ru-d(3z2-r2) orbitals. Coadsorbed H also reduces the CO adsorption energy considerably and enhances the site preference of CO. On a Ru(0001)(1 x 1)H surface, CO adsorbs exclusively on the atop position. (C) 2001 American Institute of Physic

Ar scattering on Ru (0001): a comparison to the washboard model

The scattering of Ar atoms on a Ru (0001) surface has been studied by applying supersonic molecular beam techniques. Variation of the incidence energy (

'Magic' island formation of CO coadsorbed with H on Ru(0001)

The mutual interaction between carbon monoxide and hydrogen coadsorbed on Ru(0001) has been studied by thermal desorption spectroscopy and thermal He-atom scattering. At 250 K, the hydrogen of a fully hydrogenated Ru surface is displaced by CO. During displacement CO segregates into islands already at very low coverages. At a low exposure pressure (1.5 x 10(-9) mbar) small islands with a 'magic' size of seven molecules are formed, whilst higher exposure pressures (2 x 10(-8) mbar) lead to larger islands. This behavior is in contradiction with a mean field description of island growth introduced by Venables [Rep. Prog. Phys. 47 (1984) 399]. (C) 2002 Elsevier Science B.V. All rights reserve

Nonalloyed carbon-supported PtRu catalysts for PEMFC applications

PtRu(1:1)/C catalysts were prepared by a process that was claimed previously to lead to nonalloyed Pt and Ru particles, using twodifferent precursors, Ru nitrosyl nitrate and Ru chloride hydrate. Both X-ray diffraction and characterization by cyclic voltammetrypoint toward Pt and Ru being present as separate phases in the prepared, nonannealed catalysts. In combination with a highdispersion, this results in proton exchange membrane fuel cell (PEMFC) anode electrocatalysts. These PEMFCs have improvedhydrogen oxidation activity and CO tolerance

The dynamic interaction of CO with Ru(0001) in the presence of adsorbed CO and hydrogen

This study deals with the dynamic interaction of CO with the bare Ru(0001), the fully hydrogen- and fully CO-covered ruthenium surface. Molecular beam techniques are applied to investigate the potential energy surface of the ruthenium CO interaction and the chemically modified surfaces. The clean surface shows all properties of a deep uniform chemisorption well with a strong rotational anisotropy. The strong chemically attractive interaction can be diminished by CO adsorption, which leads to zero sticking, even at translational energies as high as 1.2 eV. The angular distribution shows a substantial broadening compared to the clean surface. As shown recently, in the case of hydrogen, CO adsorption turns into an activated process with the atop position being the only available adsorption site. Scattering CO molecules from the hydrogen-covered surface leads to very narrow angular distributions. The collisions are mainly quasi-elastic

Nonalloyed carbon-supported PtRu catalysts for PEMFC applications

PtRu(1:1)/C catalysts were prepared by a process that was claimed previously to lead to nonalloyed Pt and Ru particles, using twodifferent precursors, Ru nitrosyl nitrate and Ru chloride hydrate. Both X-ray diffraction and characterization by cyclic voltammetrypoint toward Pt and Ru being present as separate phases in the prepared, nonannealed catalysts. In combination with a highdispersion, this results in proton exchange membrane fuel cell (PEMFC) anode electrocatalysts. These PEMFCs have improvedhydrogen oxidation activity and CO tolerance