Adsorption of methyl radicals on the oxygen-modified molybdenum(100) surface

Smudde, George H.; Yu, Min; Stair, Peter C.

doi:10.1021/ja00058a053

Cited by 26 publications

(30 citation statements)

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“…Both are presumably due to the hydrogenation of methylene species, but one reaction takes place in the presence of iodine whereas the other does not. Note that when methyl species are adsorbed on oxygencovered Mo(100), where the oxygen coverage is >1 monolayer, methane reactively forms by methyl hydrogenation at ~450 K [18] This temperature is similar to, but somewhat higher than that found for the kinetics of methane formation from alkenes on oxygen-covered Mo(100).…”

Section: Introductionsupporting

confidence: 59%

“…This reacts to form adsorbed iodine and a methyl species. Note that there are other strategies for adsorbing methyl species onto transition metals surfaces, for example, by generating methyl radicals directly by thermally decomposing diazomethane in a heated dosing tube [ 18]. Another impetus for investigating the chemistry of methyl species formed from methyl iodide is that the methane formation kinetics after methylene iodide adsorption are different from those found following ethylene adsorption where in the former case methane desorbs at ~230 K and at ~390 K in the latter.…”

Section: Introductionmentioning

confidence: 99%

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The chemistry of methyl iodide on Mo(100): formation and reaction of adsorbed methyl species

Wu¹,

Molero²

1998

Surface Science

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The adsorption of methyl iodide is studled on Mo (100) where ultraviolet photoelectron spectroscopy shows that the methyl lo&de thermally decomposes to form methyl species on warming to ~200 K This self-hydrogenates to yMd methane which desorbs at ~230 K and predosmg the surface with deuterium forms essentially only CH3D lndxcatmg that the methyl species reacts with adsorbed hydrogen and that there is httle H-D exchange This methane desorptlon temperature is identical to that found when methylene species are grafted on the surface by adsorbmg methylene iodide m&catmg that methyl hydrogenation to methane is the rate-hmmng step This temperature is substantmlly lower than that at which methyl and methylene species yield methane from dean and oxygen-covered Mo(100) when formed by other routes It is proposed that this is due to the effect of relatively large iodine atoms adsorbed m the four-fold hollow site affecting neighboring (either atop or bridge) sites

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Section: Introductionsupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

The chemistry of methyl iodide on Mo(100): formation and reaction of adsorbed methyl species

Wu¹,

Molero²

1998

Surface Science

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“…High-resolution electron energy loss spectroscopy experiments 34 showed that the CH 3 group is bound to the surface Mo atoms rather than the surface oxygen during the adsorption of methyl on the oxygen-modified Mo͑100͒ surface, so the nonmetal components only play the electronic effect and does not participate in C-N bond cleavage. In fact, it is difficult to tell the difference between ligand effect and ensemble effect.…”

Section: 30mentioning

confidence: 99%

First-principles analysis of the C–N bond scission of methylamine on Mo-based model catalysts

Tao

et al. 2010

The Journal of Chemical Physics

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The C-N bond breaking of methylamine on clean, carbon ͑nitrogen, oxygen͒-modified Mo͑100͒ ͓denoted as Mo͑100͒ and Mo͑100͒-C͑N,O͒, respectively͔, Mo 2 C͑100͒, MoN͑100͒, and Pt͑100͒ surfaces has been investigated by the first-principles density functional theory ͑DFT͒ calculations. The results show that the reaction barriers of the C-N bond breaking in CH 3 NH 2 on Mo͑100͒-C͑N,O͒ are higher than that on clean Mo͑100͒. The calculated energy barrier can be correlated linearly with the density of Mo 4d states at the Fermi level after the adsorption of CH 3 NH 2 for those surfaces. Moreover, the DFT results show that the subsurface atom, e.g., carbon, can reduce the reaction barrier. In addition, We noticed that the activation energies for the C-N bond breaking on Mo 2 C͑100͒ and MoN͑100͒ are similar to that on Pt͑100͒, suggesting that the catalytic properties of the transition metal carbides and nitrides for C-N bond scission of CH 3 NH 2 might be very similar to the expensive Pt-group metals.

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“…37 These assignments were made based on the reference data and the TPD experiments as will be described later. 40,41 No ␤-CO was observed on the MoO x /Mo surface, indicating that no metallic Mo remains on the surface. The loss peaks for the C-D stretching vibration at ϳ2150 cm Ϫ1 and the C-O stretching vibration at ϳ1000 cm Ϫ1 decrease markedly between 400 to 450 K. The TPD spectra are shown in Fig.…”

Section: A the Sublimated Moo X Thin Filmmentioning

confidence: 99%

Application of high-resolution electron energy loss spectroscopy to the adsorption and the photoreaction of CH2I2 and CD3OD on a MoOx thin film

Nakamura

Takehiro

et al. 1995

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Highresolution electron energy loss spectroscopy and infrared spectroscopy of polymer surfaces: Highresolution and orientation effects of polytetrafluoroethylene films J. Vac. Sci. Technol. A 14, 95 (1996); 10.1116/1.579886 Adsorption and reaction of formic acid on NiO(100) films on Mo(100): Temperature programmed desorption and high resolution electron energy loss spectroscopy studiesThe adsorption and the photoreaction of CH 2 I 2 and CD 3 OD on sublimated molybdenum oxide surfaces have been studied using high-resolution electron energy loss spectroscopy combined with thermal and photoinduced desorption spectroscopy. The energy loss peaks for ͑C-H͒, ͑C-D͒, ͑C-O͒ and ␦ ͑CH 2 ͒ are detected for CH 2 I 2 and CD 3 OD adsorbed on the MoO x thin film, where the energy losses of the ͑C-H͒ stretch and ͑C-D͒ stretch are mainly caused by impact scattering. CD 3 OH adsorbed on the MoO x thin film surface photodesorbs as CD 3 OD and CD 2 O due to illumination by ultraviolet ͑UV͒ light. CH 2 I 2 adsorbs on the MoO x thin film without dissociation at room temperature, but undergoes photodissociation upon illumination by UV light via the production of intermediate vCH 2 ͑a͒ species.

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Adsorption of methyl radicals on the oxygen-modified molybdenum(100) surface

Cited by 26 publications

References 0 publications

The chemistry of methyl iodide on Mo(100): formation and reaction of adsorbed methyl species

The chemistry of methyl iodide on Mo(100): formation and reaction of adsorbed methyl species

First-principles analysis of the C–N bond scission of methylamine on Mo-based model catalysts

Application of high-resolution electron energy loss spectroscopy to the adsorption and the photoreaction of CH2I2 and CD3OD on a MoOx thin film

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