For ethylene and deuterium bromide coadsorbed on Pt(111) at 52 K, evidence is presented for photon-driven production of ethane and bromoethane. The formation of bromoethane is ascribed to a surface-aligned concerted reaction between photoexcited DBr- or its vibrationally excited, electronically quenched form, and C2H4. This reaction is more likely when the C2H4 is adsorbed over a chemisorbed layer of DBr. Ethane is best accounted for on the basis of photogenerated energetic D atoms reacting with C2H4 to form C2H4D, and the latter being hydrogenated during temperature-programmed desorption by active D atoms derived from dissociating DBr. When C2H4 and DBr are both in the first layer, the π-bonded form of ethylene reacts more readily than the di-σ-bonded form.
ASJC Scopus subject areas
- Colloid and Surface Chemistry