کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5369927 | 1388465 | 2006 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Infrared reflection absorption study of carbon monoxide adsorption on Pd/Cu(1 1 1) Infrared reflection absorption study of carbon monoxide adsorption on Pd/Cu(1 1 1)](/preview/png/5369927.png)
Pd-Cu bimetallic surfaces formed through a vacuum-deposition of Pd on Cu(1Â 1Â 1) have been discussed on the basis of carbon monoxide (CO) adsorption: CO is used as a surface probe and infrared reflection absorption (IRRAS) spectra are recorded for the CO-adsorbed surfaces. Low energy electron diffraction (LEED) patterns for the bimetallic surfaces reveal six-fold symmetry even after the deposition of 0.6Â nm. The lattice spacings estimated by the separations of reflection high-energy electron diffraction (RHEED) streaks increase with increasing Pd thickness. Room-temperature CO exposures to the bimetallic surfaces formed by the Pd depositions less than 0.3Â nm thickness generate the IRRAS bands due to the three-fold-hollow-, bridge- and linear-bonded CO to Pd atoms. In particular, on the 0.1Â nm-thick Pd surface, the linear-bonded CO band becomes apparent at an earlier stage of the exposure. In contrast, the bridge-bonded CO band dominates the IRRAS spectra for CO adsorption on the 0.6Â nm-thick Pd surface, at which the lattice spacing corresponds to that of Pd(1Â 1Â 1). A 90Â K-CO exposure to the 0.1Â nm-thick Pd surface leads to the IRRAS bands caused not only by CO-Pd but also by CO-Cu, while the Cu-related band is almost absent from the spectra for the 0.3Â nm-thick Pd surface. The results clearly reveal that local atomic structures of the outermost bimetallic surface can be discussed by the IRRAS spectra for the probe molecule.
Journal: Applied Surface Science - Volume 253, Issue 5, 30 December 2006, Pages 2540-2546