Adsorption kinetics and energetics of atomic hydrogen (deuterium) on oxygen and carbon covered V(100)

Krenn, Georg; Eibl, Christian; Mauritsch, W; Hebenstreit, E.L.D.; Варга, П.; Winkler, Adolf

doi:10.1016/s0039-6028(99)01080-8

Cited by 38 publications

(36 citation statements)

References 20 publications

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“…The mean translational energies for deuterium from V(100) + O as function of the vibrational states (m = 0,1) and the rotational states (j = 0-9) are summarized in figure 8. First of all one can see that for all m,j values the mean energy is above the thermalized value of E h i = 2kT s , with T s = 950 K, indicating activated desorption This is in agreement with the observed small sticking coefficient for molecular deuterium on the V(100) + O surface (S 0 = 5 · 10 )4 ) [54]. The second interesting result is that the molecules in the vibrational state m = 1 possess a smaller mean kinetic energy than the molecules in the m = 0 state.…”

Section: State Resolved Tof Spectroscopy On Desorbing Deuterium From supporting

confidence: 83%

“…This allows the examination of the energy partitioning in the desorption process. The V(100) sample was prepared by sputtering and annealing procedures in such a way that a stable oxygen coverage was obtained exhibiting the well known (5 · 1) LEED pattern [53,54]. This surface was exposed to atomic deuterium for extended time so that several hundred monolayers of deuterium could be dissolved in the surface near region.…”

Section: State Resolved Tof Spectroscopy On Desorbing Deuterium From mentioning

confidence: 99%

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Time-of-flight studies on catalytic model reactions

Winkler¹,

Kratzer²,

Pauer³

et al. 2007

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Time-of-flight spectroscopy (TOF) and REMPI-TOF (resonance enhanced multi-photon ionization-TOF) were applied to measure the angular and translational energy distribution, as well as the internal state resolved energy distribution of desorption and reaction products on some model systems. Desorption of hydrogen and deuterium from clean and modified Pd(111) surfaces was studied, where the palladium sample was part of a permeation source. Water formation by reaction of oxygen with hydrogen on palladium was investigated by using different types of hydrogen supply: molecular H 2 exposure and atomic H exposure from the gas phase, as well as H exposure by permeating hydrogen. Vanadium oxide nanostructures on Pd(111) were prepared and the influence on D 2 desorption and D 2 O production was investigated with the permeation technique. Additionally, deuterium desorption from sulfur and oxygen covered V(111) and V(100) surfaces was studied by TOF and REMPI-TOF spectroscopy. From the TOF spectra information concerning the reaction and desorption dynamics (activation barriers) could be gained.

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Section: State Resolved Tof Spectroscopy On Desorbing Deuterium From supporting

confidence: 83%

Section: State Resolved Tof Spectroscopy On Desorbing Deuterium From mentioning

confidence: 99%

Time-of-flight studies on catalytic model reactions

Winkler¹,

Kratzer²,

Pauer³

et al. 2007

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“…A reduction of vanadium oxide at reaction temperature is not feasible. Oxygen adsorbed on vanadium singlecrystal surfaces cannot be removed as water by dosing hydrogen molecules or atoms [24] but may be dissolved in the vanadium bulk. Vanadium carbides also have a low reactivity toward hydrogen.…”

Section: 32mentioning

confidence: 99%

The vanadium subsurface alloy on polycrystalline rhodium: formation and catalytic properties

Reichl

Hayek

2004

Journal of Catalysis

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“…3͒, and therefore one can estimate the ␣ H magnitude to be in the order of at least 0.1. Atomic beam experiments with a number of metals covered by nonmetallic monolayers yielded ␣ H value in the range of 0.1-0.4 at T S ജ 298 K, 1,4,5,22,26,27 while the data on the superpermeation of H atoms through Nb covered by oxygen monolayer [1][2][3]17,18 are most self-consistent at ␣ H Ϸ 0.2-0.3. Taking that into account, we set ␣ H Ϸ 0.25 in Fig.…”

Section: Resultsmentioning

confidence: 97%

“…The desorbed atoms pos-sess the temperature of the surface in this case, i.e., ␤ is expected to be close to 1. Sticking of H atoms into a weakly bonded surface state was observed in the case of V͑100͒ covered by residual impurities ͑a monolayer of oxygen and carbon͒: 5 at T S = 90 K, atoms were sticking with a probability greater than 0.6 and then released at heating to T S Ϸ 150 K ͑though it is not clear whether as H or H 2 ͒.…”

Section: B Sticking Of H Atoms At Oxygen-covered Nbmentioning

confidence: 99%

Effects of bulk impurity concentration on the reactivity of metal surface: Sticking of hydrogen molecules and atoms to polycrystalline Nb containing oxygen

Hatano

Watanabe

Livshits

et al. 2007

The Journal of Chemical Physics

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Nonmetallic impurities segregated onto metal surfaces are able to drastically decrease the chemical reactivity of metals. In the present paper, effects of bulk impurities on the reactivity of metallic surfaces were investigated in a wide temperature range on an example of the sticking of hydrogen molecules and atoms to Nb ͓polycrystalline, with mainly ͑100͔͒ containing solute oxygen. At all the investigated surface temperatures, T S ͑300-1400 K͒, we found the bulk oxygen concentration C O to have a strong effect on the integral probability, ␣ H 2 , of dissociative sticking of H 2 molecules followed by hydrogen solution in the metal lattice: ␣ H 2 monotonically decreased by orders of magnitude with increasing C O from 0.03 to 1.5 at. %. The sticking coefficient ␣ H 2 was found to depend on T S but not on the gas temperature. The effect of C O on ␣ H 2 is explained by the presence of oxygen-free sites ͑holes in coverage͒ serving as active centers of the surface reaction in the oxygen monolayer upon Nb. In contrast to H 2 molecules, H atoms were found to stick to, and be dissolved in, oxygen-covered Nb with a probability comparable to 1, depending neither on C O nor on T S . This proves that, unlike H 2 molecules, H atoms do stick to be dissolved mainly through regular surface sites covered by oxygen and not through the holes in coverage.

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Adsorption kinetics and energetics of atomic hydrogen (deuterium) on oxygen and carbon covered V(100)

Cited by 38 publications

References 20 publications

Time-of-flight studies on catalytic model reactions

Time-of-flight studies on catalytic model reactions

The vanadium subsurface alloy on polycrystalline rhodium: formation and catalytic properties

Effects of bulk impurity concentration on the reactivity of metal surface: Sticking of hydrogen molecules and atoms to polycrystalline Nb containing oxygen

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