Effect of CO on hydrogen thermal desorption from Fe(100)

Burke, Maria; Madix, Robert J.

doi:10.1016/0039-6028(90)90516-b

Cited by 61 publications

(67 citation statements)

References 40 publications

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“…7a and b show that the dissociation is hindered by the formation of energy barriers in the entrance channel of the potential energy surface, however, the hydrogen dissociation is still exothermic, i.e., the poisoning is not due to site-blocking. This result is actually at variance with measurements of the hydrogen saturation coverage as a function of the sulfur coverage [42]. In these experiments a linear decrease of the hydrogen saturation coverage with increasing sulfur coverages was found.…”

Section: Dissociative Adsorption At a Sulfur-covered Transition Mcontrasting

confidence: 52%

“…Traditionally an "trial and error" approach was used to improve the activity of a catalyst by adding some substances. On Pd(100) it is experimentally wellknown that the presence of sulfur leads to a large reducting of hydrogen dissociation probability [16,42]. While at the clean surface the dissociation probability is about 60% for a kinetic energy of E i = 0.05 eV, at the sulfurcovered surface it drops below 1% at the same energy [16].…”

Section: Dissociative Adsorption At a Sulfur-covered Transition Mmentioning

confidence: 99%

“…Since the hydrogen sticking probability depends sensitively on the sulfur coverage [16,42], a small uncertainty in the sulfur coverage can have a decisive influence. However, as noted above, while the DFT calculations yield that the poisoning is caused by the building up of barriers hindering the dissociation, the vanishing hydrogen saturation coverage for roughly a quarter monolayer of adsorbed sulfur [42] suggests that any attractive adsorption sites for hydrogen have disappeared due to the presence of sulfur. These seemingly contradicting results and also the discrepancy between calculated and measured molecular beam sticking probabilities could be reconciled if subsurface sulfur plays an important role for the hydrogen adsorption energies.…”

Section: Dissociative Adsorption At a Sulfur-covered Transition Mmentioning

confidence: 99%

“…The sulfur coverage was then monitored through the ratio of the Auger peaks S 132 /Pd 330 [16]. Since the hydrogen sticking probability depends sensitively on the sulfur coverage [16,42], a small uncertainty in the sulfur coverage can have a decisive influence. However, as noted above, while the DFT calculations yield that the poisoning is caused by the building up of barriers hindering the dissociation, the vanishing hydrogen saturation coverage for roughly a quarter monolayer of adsorbed sulfur [42] suggests that any attractive adsorption sites for hydrogen have disappeared due to the presence of sulfur.…”

Section: Dissociative Adsorption At a Sulfur-covered Transition Mmentioning

confidence: 99%

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Hydrogen dissociation on metal surfaces - a model system for reactions on surfaces

Groß¹

1998

Applied Physics A: Materials Science & Processing

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Reactions on surfaces play an important role in many technological applications. Since these processes are often rather complex, one tries to understand single steps of these complicated reactions by investigating simpler system. In particular the hydrogen dissociation on surfaces serves as such a model system. There has been much progress in recent years in the theoretical description of reactions on surfaces by high-dimensional dynamics simulations on potential energy surfaces which are derived from ab initio total energy calculations. In this brief review I will focus on the hydrogen dissociation on the clean and sulfur-covered Pd(100) surface. These calculations established the importance of dynamical concepts like the steering effect. The electronic structure calculations allow furthermore the determination of the factors that determine the reactivity of a particular surface. This will be demonstrated for the poisoning of hydrogen dissociation by sulfur adsorption on the Pd(100) surface. In addition, quantum effects in the dynamics can be assessed by comparing the results of classical with quantum dynamical calculations on the same potential energy surface. 68.35.Ja, 82.20.Kh, 82.65.Pa

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Section: Dissociative Adsorption At a Sulfur-covered Transition Mcontrasting

confidence: 52%

Section: Dissociative Adsorption At a Sulfur-covered Transition Mmentioning

confidence: 99%

Section: Dissociative Adsorption At a Sulfur-covered Transition Mmentioning

confidence: 99%

Section: Dissociative Adsorption At a Sulfur-covered Transition Mmentioning

confidence: 99%

See 2 more Smart Citations

Hydrogen dissociation on metal surfaces - a model system for reactions on surfaces

Groß¹

1998

Applied Physics A: Materials Science & Processing

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show abstract

“…There are some methods such as thermal desorption methods 4) and electrochemical methods 5) using DevanathanStachurski type 6) diffusion cell to evaluate the behavior of the hydrogen penetration and permeation. The information of total amount of hydrogen penetrated to metals can be obtained by these methods, however, they are difficult to give the information for distribution of penetration (or permeation) hydrogen.…”

Section: Introductionmentioning

confidence: 99%