High-resolution electron energy-loss spectroscopy (HREELS) has been used to study carbon monoxide adsorption on mixed overlayers of Cu on Ni(111) and Ni on Cu(111). The mixed CuNi layers are formed by controlling deposition and annealing temperatures, and metal overlayer coverage. HREELS shows top and bridge CO adsorption on sites which resemble CO on pure Cu and Ni (111) surfaces. We also observe a new mixed bridging site species in which CO is bridge bonded between Cu and Ni atoms. The mixed bridging species is only observed at high CO coverages and low temperatures (<130 K), and appears coincident with a decrease in Ni-CO top site occupancy. A thermodynamic model is proposed to explain the CO transfer from the Ni top to the mixed NiCu bridge sites.
|Number of pages||6|
|Journal||Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films|
|Publication status||Published - 1989|
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films