Adsorption of carbon monoxide on ruthenium-modified platinum(100) surfaces as studied by time-resolved infrared reflection absorption spectroscopy in ultrahigh vacuum

The adsorption of CO onto Ru-modified Pt(100) surfaces prepared by chemical vapor deposition was investigated using infrared reflection absorption spectroscopy (IRAS) in ultrahigh vacuum (UHV). A sequence of IRAS spectra recorded in the COlin stretching region for saturation CO exposures onto a progressively annealed (2.5 hour intervals at 650K) Ru/Pt(100) surfaces was characterized by the presence of a clearly identifiable isosbestic point. Time-resolved (tr) IRAS spectra were also collected for a wide range of CO exposures onto systematically annealed Ru/Pt(100) surfaces. Based on the statistical analyses of these data, annealing of these Ru/Pt surfaces at 650K induces the gradual surface incorporation of Ru into Pt, thus enriching the surface with Pt while reducing the effective Ru coverage.; Interfacial dynamics of various amounts of D2O coadsorbed onto saturated CO/Pt(100) surfaces at 105K in ultrahigh vacuum were studied with tr-IRAS. The linear- and bridge-bonded CO stretching features were found to change in intensity and shift toward lower energies as a function of time at fixed CO and D2O coverages. These findings indicate that the interfacial dynamics involve a gradual rearrangement of adsorbed CO and D2O on the surface to yield surface solvated CO. Furthermore, tr-IRAS spectra for the coadsorption of small amounts of D2O (ca. 0.01L exposures) on CO(sat)/Pt(100) surfaces yielded a component which remained fixed in position in direct contrast to the red shifts observed for all other peaks. As determined by statistical analyses, it was determined that two CO adsorption sites exist and for which the rate of hydration rate of adsorbed CO is larger for the (5 x 20) compared to the (1 x 1) phases.; Tetrahedral carbon films incorporating nitrogen (taC:N) have been produced on Si, Ta, Ti and electrochemically roughened Ag surfaces using a filtered cathodic vacuum arc (FCVA) carbon ion source in the presence of nitrogen gas at reduced pressure. These films were characterized with X-ray Photoelectron Spectroscopy (depth profiling), Raman spectroscopy, and various electrochemical techniques.