Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5369429 | Applied Surface Science | 2008 | 5 Pages |
We investigated carbon monoxide (CO) adsorption and desorption behaviors on 0.1-nm-, 0.15-nm-, and 0.3-nm-thick-Pd-deposited Cu(1Â 1Â 0) surfaces using infrared reflection absorption (IRRAS) and temperature-programmed desorption (TPD) spectroscopic methods. CO was exposed to the 0.1-nm-thick-Pd/Cu(1Â 1Â 0) surface at the substrate temperature of 90Â K. The IR band attributable to CO bonded to Cu atoms emerged at 2092Â cmâ1: the band was located at 2100Â cmâ1 at saturation coverage, with a shoulder at 2110Â cmâ1. In addition to these bands, weak absorptions attributable to the PdCO bonds appeared at 2050 and 1960Â cmâ1. With increasing Pd thickness, the Pd related-bands became increasingly prominent. Particularly at the early stage of exposure, the band at 2115Â cmâ1 became visible. The band at 2117Â cmâ1 dominated the spectra all through the exposures for the 0.3-nm-thick-Pd surface. The TPD spectra of the surfaces showed two remarkable features at around 220-250 and 320-390Â K, ascribable ,respectively, to CuCO and PdCO. The desorption peaks shifted to higher temperatures with increasing Pd thickness. Based on the TPD and IRRAS results, we discuss the adsorption-desorption behaviors of CO on the Pd/Cu(1Â 1Â 0) surfaces.