Photochemical reactions of cis- and trans-1,2-dichloroethene adsorbed on Pd(111) and Pt(111)
Abstract
The photochemical behaviors of cis- and trans-1,2-dichloroethene (DCE) adsorbed on Pd(111) and Pt(111) surfaces have been studied using electron energy loss spectroscopy (EELS). For multilayer coverage on either metal surface, irradiation of physisorbed DCE at 110 K with broad band irradiation (λ>200 nm) results in photoisomerization, cis-trans. For monolayer coverage on Pt(111) at 110 K, photolysis of chemisorbed DCE causes loss of the two chlorine atoms to form a single hydrocarbon product, chemisorbed acetylene. Apparently, for λ>237 nm, the chlorine atoms remain bound to the platinum surface whereas for shorter wavelengths, λ>200 nm, the chlorine atoms leave the surface. These results are interpretable in terms of singlet excitation of the chemisorbed alkane followed by chlorine elimination on an excited singlet reaction surface. This study indicates that photochemistry of molecules chemisorbed on a metal surface is possible despite the proximity of the conducting surface. It shows that energy relaxation processes connected with this proximity are not prohibitively fast.
- Publication:
-
Journal of Chemical Physics
- Pub Date:
- April 1988
- DOI:
- 10.1063/1.453807
- Bibcode:
- 1988JChPh..88.4484G