Potential-induced migration of top-layer atoms and molecules on Pt(110) electrode surface studied by infrared reflection absorption spectroscopy

✍ Scribed by Hirohito Ogasawara; Junji Inukai; Masatoki Ito

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 570 KB
• Volume: 198
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(92)85070-q

✦ Synopsis

The reconstruction process on a clean Pt ( 110) surface was monitored by infrared reflection absorption spectra of CO on the surface. The adsorbate-induced phase transition from the (1 x2 )-Pt (110) to the ( I x I )-Pt( 110) structure was completely suppressed under negative electrode potentials. The migration of copper ad-atoms on the Pt( 110) surface prepared by underpotential deposition was also controlled by the electrode potential. At negative potentials, the mobility of the copper ad-atoms was depressed strongly, and the copper ad-atoms did not form a uniform film. Diffusion of the copper atoms started at a relatively positive potential. Thus the reconstruction of a Pt ( 110) surface and the migration of copper ad-atoms did not proceed under highly negative electrode potentials at room temperature, 1. Introduction Structures and phase transitions on single-crystal surfaces have recently been studied by several workers. A well-known example is the reconstruction in CO chemisorption on Pt ( 110) under UHV conditions investigated by LEED and vibrational spectroscopy [ I-31. A clean Pt ( 110) surface exhibits a structure in which every second row in the [ 1 IO] direction is missing, and removal of this "missing row" structure is induced by CO adsorption [ 11. As for the UHV studies, fhe phase transition proceeds rapidly at temperatures higher than 280 K, but it never occurs at temperatures lower than 160 K [ 21.

Recently, static structures as well as phase transitions on a single-crystal electrode in electrochemical processes have also been studied [ 4-61. The structure of CO adsorbed on each electrode surface can be determined by infrared reflection absorption spectroscopy (IRAS). There are at least two or three adsorption sites of CO on each electrode surface. The CO population on each site can be controlled by