scholarly journals Hydrogen Adsorption on N-Modified Ni(755) Surface. Evidence of a Molecular “Precursor” State

1986 ◽  
Vol 15 (9) ◽  
pp. 1429-1432 ◽  
Author(s):  
Hisakazu Nozoye
Keyword(s):  
Hydrogen Adsorption ◽  
Precursor State ◽  
Molecular Precursor

Atomically Smooth Ultrathin Oxide Layers on SI(113)

1999 ◽  
Vol 567 ◽  
Author(s):  
H.-J. Müssig ◽  
J. Dabrowski ◽  
S. Hinrich
Keyword(s):  
Elevated Temperatures ◽  
Oxidation Mechanism ◽  
Dissociative Chemisorption ◽  
Initial Oxidation ◽  
Precursor State ◽  
Oxide Layers ◽  
Adsorption Sites ◽  
Molecular Precursor ◽  
Diffusion Paths ◽  
Ultrathin Oxide

ABSTRACTWe report the first direct observation of dissociative chemisorption of oxygen molecules on a silicon surface at room temperature via a molecular precursor state. We link this to the fact that smooth oxide layers can be grown easily on Si(113). The process of initial oxidation is discussed in terms of surface diffusion paths and surface stress. First ab initiocalculations help elucidate the favored adsorption sites and the oxidation mechanism. Experimental evidence was found for bond geometries resulting in the quasi-epitaxial growth of a chemisorption layer on the substrate at elevated temperatures (600°C). In contrast to the first stages of Si(001) oxidation, neither defects nor the ejection of Si atoms plays a significant role during the initial oxidation of Si(113).

The role of the precursor state and the mutual interaction in hydrogen adsorption on thin iron films

1985 ◽  
Vol 151 (2-3) ◽  
pp. L166-L170 ◽  
Author(s):  
E. Nowicka ◽  
Z. Wolfram ◽  
W. Lisowski ◽  
R. Duś
Keyword(s):  
Hydrogen Adsorption ◽  
Mutual Interaction ◽  
Iron Films ◽  
Precursor State

The role of the precursor state and the mutual interaction in hydrogen adsorption on thin iron films

1985 ◽  
Vol 151 (2-3) ◽  
pp. L166-L170
Author(s):  
E. Nowicka ◽  
Z. Wolfram ◽  
W. Lisowski ◽  
R. Duś
Keyword(s):  
Hydrogen Adsorption ◽  
Mutual Interaction ◽  
Iron Films ◽  
Precursor State

High-Entropy Alloys as Catalysts for the CO2 and CO Reduction Reactions

2019 ◽  
Author(s):  
Jack Pedersen ◽  
Thomas Batchelor ◽  
Alexander Bagger ◽  
Jan Rossmeisl
Keyword(s):  
Density Functional ◽  
Rational Design ◽  
Hydrogen Adsorption ◽  
Co Adsorption ◽  
Reduction Reaction ◽  
Supervised Machine Learning ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Co Reduction ◽  
Disordered Alloy

Using the high-entropy alloys (HEAs) CoCuGaNiZn and AgAuCuPdPt as starting points we provide a framework for tuning the composition of disordered multi-metallic alloys to control the selectivity and activity of the reduction of carbon dioxide (CO2) to highly reduced compounds. By combining density functional theory (DFT) with supervised machine learning we predicted the CO and hydrogen (H) adsorption energies of all surface sites on the (111) surface of the two HEAs. This allowed an optimization for the HEA compositions with increased likelihood for sites with weak hydrogen adsorption{to suppress the formation of molecular hydrogen (H2) and with strong CO adsorption to favor the reduction of CO. This led to the discovery of several disordered alloy catalyst candidates for which selectivity towards highly reduced carbon compounds is expected, as well as insights into the rational design of disordered alloy catalysts for the CO2 and CO reduction reaction.

Control of hydrogen absorption by nickel films obtained upon magnetic spraying of zirconium alloy using the thermoEMF method

2020 ◽  
Vol 86 (8) ◽  
pp. 32-37
Author(s):  
V. V. Larionov ◽  
Xu Shupeng ◽  
V. N. Kudiyarov
Keyword(s):  
Magnetron Sputtering ◽  
Hydrogen Concentration ◽  
Hydrogen Absorption ◽  
Zirconium Alloy ◽  
Hydrogen Adsorption ◽  
Zirconium Alloys ◽  
Nickel Film ◽  
Protective Film ◽  
Nickel Films ◽  
Hydrogen Penetration

Nickel films formed on the surface of zirconium alloys are often used to protect materials against hydrogen penetration. Hydrogen adsorption on nickel is faster since the latter actively interacts with hydrogen, oxidizes and forms a protective film. The goal of the study is to develop a method providing control of hydrogen absorption by nickel films during vacuum-magnetron sputtering and hydrogenation via measuring thermoEMF. Zirconium alloy E110 was saturated from the gas phase with hydrogen at a temperature of 350°C and a pressure of 2 atm. A specialized Rainbow Spectrum unit was used for coating. It is shown that a nickel film present on the surface significantly affects the hydrogen penetration into the alloy. A coating with a thickness of more than 2 μm deposited by magnetron sputtering on the surface of a zirconium alloy with 1% Nb, almost completely protects the alloy against hydrogen penetration. The magnitude of thermoemf depends on the hydrogen concentration in the zirconium alloy and film thickness. An analysis of the hysteresis width of the thermoEMF temperature loop and a method for determining the effective activation energy of the conductivity of a hydrogenated material coated with a nickel film are presented. The results of the study can be used in assessing the hydrogen concentration and, hence, corrosion protection of the material.

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