Chlorine-oxygen interactions and the role of chlorine in ethylene oxidation over Ag(111)

✍ Scribed by S.A. Tan; R.B. Grant; R.M. Lambert

• Book ID: 113178009
• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 751 KB
• Volume: 100
• Category: Article
• ISSN: 0021-9517
• DOI: 10.1016/0021-9517(86)90105-3

✦ Synopsis

Coadsorbed chlorine enhances the surface + bulk transport of chemisorbed oxygen on Ag(ll1). Preadsorbed chlorine progressively blocks the chemisorption of atomic oxygen (O(a)); O(a) uptake is completely suppressed at 0 Cl = 0.25. Reactor studies of ethylene oxidation in the presence of adsorbed chlorine show that Cl reduces overall activity and increases selectivity towards ethylene oxide formation. All catalytic activity is quenched for chlorine fractional coverages ~0.25. This strongly suggests that O(a) is the crucial surface species responsible for both selective and total oxidation of ethylene. Temperature-programmed reaction data indicate that under certain conditions Cl exerts an apparent antipromoter effect. The relevant conditions are remote from those which prevail in a typical flow reactor.