Ethylene adsorption on Pd(111) studied using infrared reflection-ab sorption spectroscopy

SURFACE SCIENCE

卷:511

Article

Stacchiola, D ; Burkholder, L ; Tysoe, WT

关键词: reflection spectroscopy;    chemisorption;    vibrations of adsorbed molecules;    palladium;    alkenes;    hydrogen atom;    carbon;    monoxide;    single crystal surfaces;   

DOI  :  10.1016/S0039-6028(02)01498-X

来源: Elsevier

【 摘 要 】

The adsorption of ethylene has been studied on clean and hydrogen-covered Pd(1 1 1) using reflection-absorption infrared spectroscopy and molecular beam methods. Using a correlation diagram, in which vibrational frequencies are plotted versus a an parameter proposed by Stuve and Madix, shows that ethylene is substantially rehybridized on Pd(1 1 1) having a an parameter intermediate between those of ethylene on Ni(1 1 1) and Ru(0 0 1). In contrast, when ethylene adsorbs on hydrogen-covered Pd(1 1 1), only pi-bonded species are detected. An additional species appears exhibiting a characteristic frequency of 957 cm(-1) when Pd(1 1 1) is cooled to similar to80 K and the system pressurized with similar to10(-5) Torr of ethylene. This species also appears on a CO-saturated Pd(1 1 1) surface. Molecular beam measurements show that its coverage reaches similar to1.3 ML indicating that it is due to ethylene adsorbed in the second and subsequent layers. (C) 2002 Elsevier Science B.V. All rights reserved.

【 授权许可】

Free