The effects of preadsorbed CO on the chemistry of CH3 and CH3I on Pd{111}

Chen, J.-J.; Winograd, Nicholas

doi:10.1016/0039-6028(94)90006-x

Cited by 32 publications

(28 citation statements)

References 45 publications

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“…Methane now desorbs in a single state centered at 209 K with mass spectrometer ionizer intensity at 20, 18 and 4 amu with a small amount of intensity at 19 amu. This is in good agreement with the desorption temperature of CD 3 H from hydrogen-contaminated Pd(1 1 1) [12]. The 19-amu signal is also centered at 209 K indicating that this feature is not due to the interaction of adsorbed CD 3 species with residual hydrogen in the sample.…”

Section: à6supporting

confidence: 83%

“…A temperature of 120 K corresponds to the multilayer desorption temperature in TPD (Fig. 1) and also that at which C-I bond cleavage takes place (between 110 and 150 K [12,14]). Thus, these features may either be assigned to compressed methyl iodide species on the Pd(1 1 1) surface [11] or to adsorbed methyl species and, most likely, to a combination of both.…”

Section: à6mentioning

confidence: 99%

“…The spectrum formed by heating to 170 K (when all of the multilayer has desorbed (Fig. 1), and C-I bond cleavage is complete [12,14]) shows the appearance of an additional sharper feature at 1225 cm À1 . As the surface is heated, the broad 1215-cm À1 mode loses some of its intensity and the 1225-cm À1 peak becomes sharper.…”

Section: à6mentioning

confidence: 99%

“…Methane formation is found due to the reductive elimination of methyl species on other transition metals surfaces at 215 K on Pd(1 0 0) [9], 230 K on Ni(1 0 0) [10] and 260 K on Pt(1 1 1) [11]. Previous temperature-programmed desorption (TPD) studies of CH 3 I and CD 3 I on Pd(1 1 1) found only methane desorption at $210 K due to reaction of methyl species with hydrogen contamination present in the bulk of the sample [12]. Hydrogen background contamination of palladium has been shown to be a problem even under ultrahigh vacuum conditions.…”

Section: Introductionmentioning

confidence: 99%

“…The X-ray photoelectron spectra (XPS) of methyl iodide on Pd(1 1 1) have been collected previously [12,14] and reveal that substantial C-I bond cleavage is underway by 110 K and is essentially complete by 150 K. Similar conclusions were arrived at on Pd(1 0 0) [9], where XPS similarly indicated that C-I bond cleavage occurs between 150 and 170 K, so at slightly higher temperatures than on Pd(1 1 1).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

An infrared spectroscopic and temperature-programmed desorption study of methyl iodide hydrogenation on Pd()

Stacchiola

Wang

2003

Surface Science

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Section: à6supporting

confidence: 83%

Section: à6mentioning

confidence: 99%

Section: à6mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An infrared spectroscopic and temperature-programmed desorption study of methyl iodide hydrogenation on Pd()

Stacchiola

Wang

2003

Surface Science

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The use of XPS spectra for the study of reaction mechanisms: the atom inventory method

Humeres

Castro

Moreira

et al. 2008

J of Physical Organic Chem

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X‐ray photoelectron spectroscopy (XPS) allows the analysis of the surface atomic composition of a solid and can be used for mechanistic studies of solid–gas and solid–liquid reactions. The change of atomic composition of a surface after a reaction can be calculated considering hypothetical mechanisms based on the known reactivity of the organic moieties bound to the solid surface. Atom inventory of the elements involved in the reactions was used to quantify the components of the XPS spectrum after the reaction and consequently the change of concentration in at%. The method was used to study the basic hydrolysis and photolysis of the intermediates bound to the carbon matrix after the reduction of SO2 on activated carbon. Consistent mechanisms were postulated for these reactions. Basic hydrolysis hydrolyzed the sultine intermediate, and the attack of hydroxide ion on the episulfide formed a sulfide anion, eliminating S2− in a consecutive step. Laser photolysis of modified activated carbon in t‐butanol showed the insertion of the organic moiety in the carbon matrix with expulsion of an SO2 radical anion that oxidized to ${\rm SO}_4^{2 - } $. Copyright © 2008 John Wiley & Sons, Ltd.

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Kinetics and mechanisms in flow systems: reduction of SO₂ on carbons

Humeres

Moreira

2012

J of Physical Organic Chem

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Surface‐science studies of some reactions have allowed postulating the mechanisms using a variety of techniques. The surface chemistry of Group IV elements has been particularly studied recently because Si, Ge, and C are semiconductors, and the surface organic chemistry to functionalize these elements has seen immense progress in recent years. In this review article we describe the methodology used to study the mechanism of a solid–gas reaction, the reduction of SO2 on carbons, and the necessary conditions that allowed the measurement of the solid conversion and product distribution when the kinetics was chemically controlled and the reaction had reached the steady state. The reaction was first‐order with respect to SO2 and with respect to carbon and the stoichiometry was determined from the product distribution. The reaction proceeds through two thermally stable reaction intermediates bound to the surface, a six‐membered ring 1,3,2‐dioxathiolane and a five‐membered ring 1,2‐oxathietene 2‐oxide or γ‐sultine, both species being in equilibrium. The reaction was shown to be reversible. The primary product is an episulfide that, after a series of consecutive reactions of atomic sulfur, is able to free sulfur. The reactivity of the intermediates and the episulfide was studied for several reactions and consistent mechanisms were postulated from the X‐ray photoelectron spectroscopy and solid state nuclear magnetic resonance spectra. Aminolysis and the reaction with alkyl halides resulted on the insertion of the alkyl moiety in the episulfide primary product, while the thiolysis and photolytic alcoholysis resulted in the insertion of the alkyl moiety in the oxidized intermediates. Copyright © 2012 John Wiley & Sons, Ltd.

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The effects of preadsorbed CO on the chemistry of CH3 and CH3I on Pd{111}

Cited by 32 publications

References 45 publications

An infrared spectroscopic and temperature-programmed desorption study of methyl iodide hydrogenation on Pd()

An infrared spectroscopic and temperature-programmed desorption study of methyl iodide hydrogenation on Pd()

The use of XPS spectra for the study of reaction mechanisms: the atom inventory method

Kinetics and mechanisms in flow systems: reduction of SO₂ on carbons

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The effects of preadsorbed CO on the chemistry of CH3 and CH3I on Pd{111}

Cited by 32 publications

References 45 publications

An infrared spectroscopic and temperature-programmed desorption study of methyl iodide hydrogenation on Pd()

An infrared spectroscopic and temperature-programmed desorption study of methyl iodide hydrogenation on Pd()

The use of XPS spectra for the study of reaction mechanisms: the atom inventory method

Kinetics and mechanisms in flow systems: reduction of SO2 on carbons

Contact Info

Product

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Kinetics and mechanisms in flow systems: reduction of SO₂ on carbons