Surface diffusion of potassium coadsorbed with CO on Ru(001): A coverage grating-optical second harmonic diffraction study

I. M. Danziger, B. Hallac, M. Asscher*

*Corresponding author for this work

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4 Scopus citations

Abstract

The effect of coadsorbed CO on potassium surface diffusion on Ru(001) has been studied using coverage grating-optical second harmonic diffraction method. The enhancement of the first-order diffraction peak at 0.06 ML of CO coadsorption coverage demonstrates the very strong electronic interaction between these coadsorbates. At an initial potassium coverage of 1.0 ML, the activation energy for the diffusion of K increases from 2.7 kcal/mol on the clean ruthenium surface to 17.0 kcal/mol in the presence of 0.06 ML CO. At 280 K, the diffusion rate coefficient drops from D = 6.4 × 10-10 cm2/s on clean ruthenium to D = 1.5 × 10-14 cm 2/s as a result of CO coadsorption. CO and K stabilize each other upon the formation of Ky-COx surface complexes that increase the apparent activation energy for potassium diffusion, thereby slowing its diffusion rate.

Original languageEnglish
Pages (from-to)17851-17856
Number of pages6
JournalJournal of Physical Chemistry B
Volume108
Issue number46
DOIs
StatePublished - 18 Nov 2004

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