Dynamics of hydrogen adsorption on promoter-and inhibitor-modified nickel surfaces

Resch, Christian; Zhukov, Vladimir A.; Lugstein, Alois; Berger, Helmut; Winkler, Adolf; Rendulic, Klaus

doi:10.1016/0301-0104(93)80023-3

Cited by 40 publications

(56 citation statements)

References 30 publications

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“…[51] They concluded that O 2 mainly poisons D 2 dissociation sterically, because electronic effects arising as a result of O 2 -induced changes in work function are small. In contrast, for H 2 dissociation on O-chemisorbed Ni(111) and Pt(111), [52,53] O acts not only to poison sterically but also to promote H 2 dissociation. In the present study, steric hindrance by CO of D 2 dissociation is also proposed.…”

mentioning

confidence: 79%

CO Blocking of D₂ Dissociative Adsorption on Ru(0001)

et al. 2008

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The influence of pre-adsorbed CO on the dissociative adsorption of D(2) on Ru(0001) is studied by molecular-beam techniques. We determine the initial dissociation probability of D(2) as a function of its kinetic energy for various CO pre-coverages between 0.00 and 0.67 monolayers (ML) at a surface temperature of 180 K. The results indicate that CO blocks D(2) dissociation and perturbs the local surface reactivity up to the nearest-neighbour Ru atoms. Non-activated sticking and dissociation become less important with increasing CO coverage, and vanish at theta(CO) approximately 0.33 ML. In addition, at high D(2) kinetic energy (>35 kJ mol(-1)) the site-blocking capability of CO decreases rapidly. These observations are attributed to a CO-induced activation barrier for D(2) dissociation in the vicinity of CO molecules.

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mentioning

confidence: 79%

CO Blocking of D₂ Dissociative Adsorption on Ru(0001)

et al. 2008

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“…The various base pressures were adjusted by intentionally leaking air into the baked UHV chamber. Only in the 10 −9 mbar pressure range and below, pure potassium desorption (from the metallic multilayer) can be observed, which is expected to take place at about 350 K. [24][25][26] However, at and above 2 × 10 −8 mbar no potassium desorbs in the temperature range where desorption of pure potassium is expected. There exist only small desorption peaks (note the logarithmic y-scale) at higher temperature, which are most probably due to cracking products of more stable potassium containing compounds.…”

Section: A Potassium Adsorption and Desorption From Micamentioning

confidence: 91%

The influence of potassium on the growth of ultra-thin films of para-hexaphenyl on muscovite mica(001)

Putsche

Tumbek

Winkler

2012

The Journal of Chemical Physics

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The interaction of potassium with mica(001) and its influence on the subsequent film growth of para-hexaphenyl (6P) was studied by Auger electron spectroscopy, thermal desorption spectroscopy, and atomic force microscopy (AFM). Freshly cleaved mica is covered with 0.5 monolayer (ML) of potassium. By intentional potassium deposition in ultra-high vacuum a saturation of 1 ML can be achieved, which is stable up to 1000 K. Additional potassium desorbs at around 350 K. The film morphology of 6P on mica(001) is significantly influenced by the potassium monolayer. On the freshly cleaved mica surface, which contains 1/2 ML of K, 6P forms needle-like islands which are composed of lying molecules. On the fully potassium covered mica surface 6P grows in form of dendritic islands, composed of standing molecules. The reason for this change is attributed to the removal of lateral electric fields which exist on the freshly cleaved mica surface, due to the specific arrangements of the atoms in the surface near region of mica.

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“…Actually, similar behavior has been observed for a number of HϩK-metal systems. 31,32 For a potassium coverage above 0.45 ML Al͑111͒ no further shift of the desorption peak can be observed. This coverage corresponds to the saturation coverage of the first layer ͑physical monolayer͒.…”

Section: B Influence Of Oxygen and Potassium On The Adsorption Of Atmentioning

confidence: 97%

Adsorption and abstraction of H(D) on clean and modified Al(111) and Ni(111) surfaces

Pölzl

Strohmeier

Winkler

1999

The Journal of Chemical Physics

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Abstraction and desorption kinetics in the reaction of H + D/Si (100) and the relation to surface structure Abstraction of atomic hydrogen by atomic deuterium from an amorphous hydrogenated silicon surfaceThe kinetics of adsorption and abstraction for the system H͑D͒ on Al͑111͒ and Ni͑111͒ has been investigated using an efficient atomic beam source, thermal desorption spectroscopy, and multiplexed mass spectrometry. The initial sticking coefficient of atomic hydrogen on Ni͑111͒ is 1.0 and independent of the angle of incidence. For H on Al͑111͒ the initial sticking coefficient is 0.6 and increases with increasing angle of incidence (S()ϳcos Ϫ0.4 ). On Al͑111͒ preadsorbed oxygen leads to a decrease of the initial sticking coefficient for H down to 0.1; potassium on the other hand has no significant influence on the initial sticking probability. On both surfaces, Ni͑111͒ and Al͑111͒, abstraction of deuterium proceeds at a surface temperature of 150 K due to impinging H atoms (HϩD→HD), with an initial abstraction coefficient of 0.20 on Al͑111͒ and 0.12 on Ni͑111͒. In the case of Al͑111͒ this coefficient is nearly independent of the initial D coverage and therefore the abstraction reaction cannot be described by a simple Eley-Rideal process, but rather by a hot-precursor mechanism. In addition to abstraction there is also a small probability for the removal of an adsorbed species by a collision induced desorption process. Abstraction of deuterium by impinging H-atoms is strongly affected by modification of the Al͑111͒ surface, either by oxygen or by potassium. Oxygen decreases the HD abstraction coefficient, probably by inhibiting the hot-precursor state of H on the surface. Potassium increases the HD abstraction rate, most likely by increasing the lifetime of atomic hydrogen in the precursor state.

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Dynamics of hydrogen adsorption on promoter-and inhibitor-modified nickel surfaces

Cited by 40 publications

References 30 publications

CO Blocking of D₂ Dissociative Adsorption on Ru(0001)

CO Blocking of D₂ Dissociative Adsorption on Ru(0001)

The influence of potassium on the growth of ultra-thin films of para-hexaphenyl on muscovite mica(001)

Adsorption and abstraction of H(D) on clean and modified Al(111) and Ni(111) surfaces

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Dynamics of hydrogen adsorption on promoter-and inhibitor-modified nickel surfaces

Cited by 40 publications

References 30 publications

CO Blocking of D2 Dissociative Adsorption on Ru(0001)

CO Blocking of D2 Dissociative Adsorption on Ru(0001)

The influence of potassium on the growth of ultra-thin films of para-hexaphenyl on muscovite mica(001)

Adsorption and abstraction of H(D) on clean and modified Al(111) and Ni(111) surfaces

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CO Blocking of D₂ Dissociative Adsorption on Ru(0001)

CO Blocking of D₂ Dissociative Adsorption on Ru(0001)