The oxidation of carbon monoxide catalyzed by Pt(111) was studied
in ultrahigh vacuum using reactive molecular beam--surface scattering.
Under all conditions studied, the reaction follows a Langmuir--Hinshelwood
mechanism: the combination of a chemisorbed CO molecule and an oxygen
adatom. When both reactants are at low coverage, the reaction proceeds
with an activation energy E(/sub LH/ =24.1 kcal/mole and a pre-exponential
upsilon/sub 4/ =0.11 cm/sup 2/ particles/sup -1/ sec/sup -1/. At
very high oxygen coverage, E(/sub LH/ decreases to about 11.7 kcal/mole
and upsilon/sub 4/ to about 2 x 10/sup -6/ cm/sup 2/ particles/sup
-1/ sec/sup -1/. This is largely attributed to the corresponding
increase in the energy of the adsorbed reactants. When a CO molecule
incident from the gas phase strikes the surface presaturated with
oxygen, it enters a weakly held precursor state to chemisorption.
Desorption from this state causes a decrease in chemisorption probability
with temperature. Once chemisorbed, the CO molecule then has almost
unit probability of reacting to produce CO/sub 2/ below 540 K. The
CO/sub 2/ product angular distribution varies from cos..gamma.. to
cos/sup 4/..gamma.. depending sensitively upon the adsorbed reactant
concentrations.
%0 Journal Article
%1 Ertl1980
%A Ertl, G.
%A Campbell,
%D 1980
%J J. Chem. Phys.
%K AND BEAMS; CARBON CATALYSIS; CHALCOGENIDES; CHEMICAL CLASSICAL COLLISIONS; COMPOUNDS; ELEMENTS ELEMENTS; GENERAL MECHANICS, METALS; MOLECULAR MOLECULE MONOXIDE; OXIDATION; OXIDES; OXYGEN PHYSICS; PLATINUM PLATINUM; QUANTUM REACTIONS; SURFACES; TRANSITION
%N 11
%P 5862--5873
%R 10.1063/1.440029
%T A molecular-beam study of the cataytic-oxidation of CO on a Pt(111)
surface
%V 73
%X The oxidation of carbon monoxide catalyzed by Pt(111) was studied
in ultrahigh vacuum using reactive molecular beam--surface scattering.
Under all conditions studied, the reaction follows a Langmuir--Hinshelwood
mechanism: the combination of a chemisorbed CO molecule and an oxygen
adatom. When both reactants are at low coverage, the reaction proceeds
with an activation energy E(/sub LH/ =24.1 kcal/mole and a pre-exponential
upsilon/sub 4/ =0.11 cm/sup 2/ particles/sup -1/ sec/sup -1/. At
very high oxygen coverage, E(/sub LH/ decreases to about 11.7 kcal/mole
and upsilon/sub 4/ to about 2 x 10/sup -6/ cm/sup 2/ particles/sup
-1/ sec/sup -1/. This is largely attributed to the corresponding
increase in the energy of the adsorbed reactants. When a CO molecule
incident from the gas phase strikes the surface presaturated with
oxygen, it enters a weakly held precursor state to chemisorption.
Desorption from this state causes a decrease in chemisorption probability
with temperature. Once chemisorbed, the CO molecule then has almost
unit probability of reacting to produce CO/sub 2/ below 540 K. The
CO/sub 2/ product angular distribution varies from cos..gamma.. to
cos/sup 4/..gamma.. depending sensitively upon the adsorbed reactant
concentrations.
@article{Ertl1980,
abstract = {The oxidation of carbon monoxide catalyzed by Pt(111) was studied
in ultrahigh vacuum using reactive molecular beam--surface scattering.
Under all conditions studied, the reaction follows a Langmuir--Hinshelwood
mechanism: the combination of a chemisorbed CO molecule and an oxygen
adatom. When both reactants are at low coverage, the reaction proceeds
with an activation energy E(/sub LH/ =24.1 kcal/mole and a pre-exponential
upsilon/sub 4/ =0.11 cm/sup 2/ particles/sup -1/ sec/sup -1/. At
very high oxygen coverage, E(/sub LH/ decreases to about 11.7 kcal/mole
and upsilon/sub 4/ to about 2 x 10/sup -6/ cm/sup 2/ particles/sup
-1/ sec/sup -1/. This is largely attributed to the corresponding
increase in the energy of the adsorbed reactants. When a CO molecule
incident from the gas phase strikes the surface presaturated with
oxygen, it enters a weakly held precursor state to chemisorption.
Desorption from this state causes a decrease in chemisorption probability
with temperature. Once chemisorbed, the CO molecule then has almost
unit probability of reacting to produce CO/sub 2/ below 540 K. The
CO/sub 2/ product angular distribution varies from cos..gamma.. to
cos/sup 4/..gamma.. depending sensitively upon the adsorbed reactant
concentrations.},
added-at = {2009-10-30T10:04:05.000+0100},
author = {Ertl, G. and Campbell},
biburl = {https://www.bibsonomy.org/bibtex/2cedca8f6a5ebc584afaca8ea570eafb9/jfischer},
doi = {10.1063/1.440029},
groups = {public},
interhash = {f94bfb5b9dc6968e8f73438be08a335b},
intrahash = {cedca8f6a5ebc584afaca8ea570eafb9},
issn = {0021-9606},
journal = {J. Chem. Phys.},
keywords = {AND BEAMS; CARBON CATALYSIS; CHALCOGENIDES; CHEMICAL CLASSICAL COLLISIONS; COMPOUNDS; ELEMENTS ELEMENTS; GENERAL MECHANICS, METALS; MOLECULAR MOLECULE MONOXIDE; OXIDATION; OXIDES; OXYGEN PHYSICS; PLATINUM PLATINUM; QUANTUM REACTIONS; SURFACES; TRANSITION},
number = 11,
pages = {5862--5873},
timestamp = {2009-10-30T10:04:11.000+0100},
title = {A molecular-beam study of the cataytic-oxidation of CO on a Pt(111)
surface},
volume = 73,
year = 1980
}