Ethylene oxide interaction with Pd surfaces: Experimental and theoretical results
Abstract
Ethylene oxide (EO) interaction with the clean Pd(110) surface was investigated under ultrahigh vacuum conditions using temperature programmed desorption/reaction. Most of the layer adsorbed at 120 K desorbs at 170-220 K, but a fraction decomposes indicating ring opening reactivity. The stoichiometric release of CO and the absence of water formation during EO decomposition on Pd(110) indicated that no more than one C-O bond was broken per molecule; subsequent C-C scission led to methane desorption at ∼325 K. Using the surface-cluster analogy, we have also applied density functional theory to assess electronic interactions involved in EO interaction with palladium surfaces. In particular, interaction with Pdn clusters (n=1,4,10) modeling the surface chemistry of EO on palladium surfaces has been investigated in this work. EO binding energies on these clusters range from 8 to 13 kcal/mol. In contrast to the experimental observation of ring opening of EO on Pd(110) and Pd(111) surfaces, theoretical results at this level do not indicate any significant perturbation of C-O and C-H bonds in adsorbed EO.
- Publication:
-
Journal of Vacuum Science Technology A: Vacuum Surfaces and Films
- Pub Date:
- May 1996
- DOI:
- 10.1116/1.579971
- Bibcode:
- 1996JVSTA..14.1469S