Coadsorption of ethylene and potassium on Pt(111). 2. Influence of potassium on the decomposition of ethylene

Journal Article · Thu Feb 22 04:00:00 EST 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100367a053· OSTI ID:6664395

Windham, R G; Koel, B E ^[1]

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1. Univ. of Colorado, Boulder (USA)

The effect of preadsorbed potassium on the decomposition of ethylene on the Pt(111) single-crystal surface has been studied by temperature programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). Potassium decreases the amount of ethylene decomposition and increases the activation energy for C-H bond cleavage. At 300 K and {theta}{sub K} = 0.12 monolayer, we observe a metastable intermediate in the decomposition of ethylene to form ethylidyne, which we propose to be ethylidene (CHCH{sub 3}). Complete dehydrogenation of ethylene occurs with an activation energy similar to that for breaking the first C-H bond, without forming a stable ethylidyne species. The authors suggest that the strong influence of potassium on the activation energies of these surface reactions, i.e., the inhibition of dehydrogenation of surface hydrocarbons, is due to the destabilization of carbon-metal {sigma} bonds in the dehydrogenated hydrocarbons species due to charge transfer from potassium to platinum.

• OSTI ID: 6664395
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:4; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ALKALI METALS
ALKENES
CALCULATION METHODS
CHEMICAL REACTIONS
CRYSTALS
DATA
DATA ANALYSIS
DECOMPOSITION
ELEMENTS
ETHYLENE
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NUMERICAL DATA
ORGANIC COMPOUNDS
PLATINUM
PLATINUM METALS
POTASSIUM
SORPTION
TRANSITION ELEMENTS