The adsorption and decomposition of trimethylamine on the clean and oxidized Mo(100) surface

Walker, B. W.; Stair, Peter C.

doi:10.1016/0039-6028(81)90268-5

Cited by 41 publications

(8 citation statements)

References 14 publications

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“…This is in agreement with the adsorption sites identified for both phenyl species 53 and benzene at Cu(110) surfaces. Interestingly, the favored adsorption site of NH(a) at Cu(110) surfaces is the short bridge site, , and as Figure e shows, if the phenyl imide is drawn using C−C and C−N bond lengths of 0.14 nm, typical values for aromatic molecules, the nitrogen can be situated in the short bridge site with the phenyl ring situated above the hollow site.…”

Section: Discussionmentioning

confidence: 98%

STM and XPS Studies of the Oxidation of Aniline at Cu(110) Surfaces

2004

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Aniline chemisorption at clean and partially oxidized Cu(110) surfaces at 293 K is compared with the reaction of a 300:1 aniline/dioxygen mixture at the same surface using STM and XPS. Limited dissociation occurs at the clean surface but in the presence of chemisorbed oxygen efficient oxy-dehydrogenation takes place with water desorption and the formation of chemisorbed phenyl imide (C6H5N(a)) with a reaction stoichiometry that changes with coverage. The adsorption site of the phenyl group is identified by STM to be the 2-fold hollow and it is proposed that the nitrogen is situated over the short bridge site. Chemisorptive replacement of oxygen gives a maximum phenyl imide concentration of 2.8 × 1014 molecules cm-2 at which coverage the surface is dominated by a mixture of three ordered domains with structures described by , , and unit meshes. Adsorption of aniline and dioxygen mixtures however results in phenyl imide concentrations up to 3.4 × 1014 cm-2 molecules cm-2 and a highly ordered biphasic structure characterized by and domains. A discrepancy between the concentrations measured by XPS and those calculated from the STM structures is discussed in terms of π-stacking of the phenyl rings in the adsorbed monolayer. Finally the chemistry of aniline is compared with that of ammonia and the importance of the NH bond strength and the basicity of the amine discussed.

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Section: Discussionmentioning

confidence: 98%

STM and XPS Studies of the Oxidation of Aniline at Cu(110) Surfaces

2004

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“…The experimental investigation of trimethylamine decomposition shows that the oxidized Mo(100) surface is less active than the corresponding clean one. 16 The N atom-modified Mo(100) surface can be used to model Mo 2 N, a typical catalyst for C-N bond breaking reactions such as hydrodenitrogenation (HDN). The adsorption and decomposition of H 3 CNH 2 on nitrogen-modified molybdenum surface with a nitrogen coverage of 0.5 ML (named as 2N-Mo(100)) have been studied by using TPD and AES, 14 and C-N bond cleavage was found.…”

Section: Introductionmentioning

confidence: 99%

Decomposition of methylamine on nitrogen atom modified Mo(100): a density functional theory study

Liu

Guo

et al. 2012

Phys. Chem. Chem. Phys.

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Three possible pathways for C-N bond breaking in methylamine have been investigated over clean Mo(100) and nitrogen atom-modified Mo(100) surfaces with a nitrogen coverage of 0.25 monolayer (ML) (N-Mo(100)) firstly, and the C-N bond breaking following the intramolecular hydrogen transfer from the CH3 to NH2 is excluded owing to the high barriers. Then methylamine decomposition starting with C-H, N-H, and C-N scission over the nitrogen atom-modified Mo(100) surface with a nitrogen coverage of 0.5 ML (2N-Mo(100)) has been systematically investigated, and the decomposition network has been mapped out. The thermochemistry and energy barriers for all the elementary steps, starting with C-H, N-H, and C-N scission, and sequential reactions from the resulting intermediates, are presented here. The most likely decomposition path is H3CNH2→ H2CNH2 + H → HCNH2 + H + H → CNH2 + H + H + H → C + NH2 + H + H + H → C + NH3 + H2→ C + NH3(g) + H2(g). For the decomposition reactions involved in the likely decomposition path, there is a linear relationship between the energy of transition state and the energy of final state. For the reverse processes of the dehydrogenation of CH, NH, NH2, it is found that there is a linear relationship between the barrier and the valency of A (A[double bond, length as m-dash]C, N, and NH).

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“…10 Moreover, the increased energy barrier of C-N bond scission on the oxygen atom precovered Mo͑100͒ may suggest that the precovered oxygen atom act as a poison rather than a promoter, which is very different from the case of the precovered O on the Cu metal and other less active metals. 30 The possible reason is that the adsorption of oxygen atom on Mo͑100͒ is too strong to active the C-N bond of CH 3 NH 2 , namely, the adsorbed oxygen atom may block the surface active site.…”

Section: 30mentioning

confidence: 99%

“…9 In addition, it has been known that the oxidized Mo͑100͒ surface is less active than the corresponding clean one from the investigation of trimethylamine decomposition. 10 On the other hand, it is usually assumed that the precovered oxygen atom on metal surfaces can enhance the catalytic activity for many other reactions. For example, water molecule dissociation on Cu͑111͒ can be promoted by the precovered oxygen atom, and the similar phenomenon can be found for the reaction of ammonia decomposition on the oxygen-modified Cu͑111͒.…”

Section: Introductionmentioning

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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The adsorption and decomposition of trimethylamine on the clean and oxidized Mo(100) surface

Cited by 41 publications

References 14 publications

STM and XPS Studies of the Oxidation of Aniline at Cu(110) Surfaces

STM and XPS Studies of the Oxidation of Aniline at Cu(110) Surfaces

Decomposition of methylamine on nitrogen atom modified Mo(100): a density functional theory study

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

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