Chemistry of acetylene on platinum (111) and (100) surfaces
- †Materials and Molecular Research Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
- Department of Chemistry, University of California, Berkeley, California, Berkeley, California 94720
- ‡Corporate Research Science Laboratories, Exxon Research and Engineering Company, P.O. Box 45, Linden, New Jersey 07036
Abstract
An ultra-high vacuum experimental study of acetylene chemisorption on Pt(111) and Pt(100) and of the reaction of hydrogen with the acetylene adsorbate has established distinguishing features of carbon-hydrogen bond breaking and making processes as a function of pressure, temperature, and surface crystallography. The rates for both processes are substantially higher on the Pt(100) surface. Net acetylene-hydrogen processes, in the temperature range of 20°C to ≈130°C, are distinctly different on the two surfaces: on Pt(100) the net reaction is hydrogen exchange (1H-2H exchange) and on Pt(111) the only detectable reaction is hydrogenation. Stereochemical differences in the acetylene adsorbate structure are considered to be a contributing factor to the differences in acetylene chemistry on these two surfaces.
