Temperature programmed desorption study of acetylene on a clean, H-covered, and O-covered Pt(111) surface

C. E. Megiris, P. Berlowitz, J. B. Butt, Harold H Kung

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47 Citations (Scopus)

Abstract

The reactions of acetylene on a clean, a H-covered and an O-covered Pt(111) surface were studied by temperature programmed desorption for various coverages of acetylene, and acetylene to H or O ratios. The desorption products were quantitatively determined. On a clean surface, acetylene decomposes to hydrogen and surface carbon. A small amount of self-hydrogenation to ethylene also occurs during decomposition. On a H-covered surface, hydrogenation to CH4, C2H6, and ethylene, and decomposition to hydrogen and surface carbon occur simultaneously. The reactions on these two surfaces can be explained by the presence of two sites. One site is a bare surface Pt atom on which decomposition is the primary reaction pathway. The other site is a Pt atom with adsorbed H on which hydrogenation is the primary reaction pathway. On the O-covered surface, the decomposition reaction takes place together with an oxidation reaction which yields CO, CO2, and water. The oxidation reaction probably proceeds via an intermediate that has a stoichiometry of CH. Results on the O-covered surface are consistent with the model that oxygen absorbs in islands, and the oxidation reaction takes place at the perimeter of the islands. These results are compared with those of ethylene reaction on the same Pt surfaces.

Original languageEnglish
Pages (from-to)184-198
Number of pages15
JournalSurface Science
Volume159
Issue number1
DOIs
Publication statusPublished - Aug 1 1985

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces

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