Effects of hydrogen adsorption on the surface-energy anisotropy of nickel

Huang, Y.Y.; Zhou, Yue; Pan, Yong

doi:10.1016/j.physb.2009.11.082

Cited by 19 publications

(12 citation statements)

References 30 publications

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“…This makes Ni(100) the most reactive surface for the CH 2 impacts. Indeed, the surface energy of Ni(100) is higher than that of Ni(111), with reported values between 1.487 and 2.426 J/m 2 for Ni(100) and 1.171 and 2.011 J/m 2 for Ni(111) . Using ReaxFF, we find a surface energy of 2.0 J/m 2 for Ni(100) and a value of 1.2 J/m 2 for Ni(111), thus corresponding well with the literature.…”

Section: Resultssupporting

confidence: 87%

“…Indeed, the surface energy of Ni(100) is higher than that of Ni(111), with reported values between 1.487 and 2.426 J/m 2 for Ni(100) and 1.171 and 2.011 J/m 2 for Ni(111). 39 Using ReaxFF, we find a surface energy of 2.0 J/m 2 for Ni(100) and a value of 1.2 J/m 2 for Ni(111), thus corresponding well with the literature. The higher surface energy of Ni(100) increases the reactivity of the surface, as observed in our results.…”

Section: Resultssupporting

confidence: 86%

“…Simulation Method. In this study, we consider four different nickel surfaces: Ni(111), which is the most stable Ni surface and the most abundant surface facet in typical nickel catalysts; 37,38 Ni(100), which has a higher surface energy and is also present in nickel catalysts; 39 and two different step-edged Ni(111) surfaces, since defect (step) sites may be formed at the catalyst surface in a plasma as a result of, for example, ion bombardment. 17,40 The Ni(111) and Ni(100) surfaces both consist of 300 atoms equally divided over 6 layers, as illustrated in Figure 1.…”

Section: T H Imentioning

confidence: 99%

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Plasma Species Interacting with Nickel Surfaces: Toward an Atomic Scale Understanding of Plasma-Catalysis

et al. 2012

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The adsorption probability and reaction behavior of CH x plasma species on various nickel catalyst surfaces is investigated by means of reactive molecular dynamics (MD) simulations using the ReaxFF potential. Such catalysts are used in the reforming of hydrocarbons and in the growth of carbon nanotubes, and further insight in the underlying mechanisms of these processes is needed to increase their applicability. Single and consecutive impacts of CH x radicals (x={1,2,3}) were performed on four different Ni surfaces, at a temperature of 400 K. The adsorption probability is shown to be related to the number of free electrons, i.e. a higher number leads to more adsorptions, and the steric hindrance caused by the hydrogen atoms bonded to the impacting CH x species. Furthermore, some of the C−H bonds break after adsorption, which generally leads to diffusion of the hydrogen atom over the surface. Additionally, these adsorbed H-atoms can be used in reactions to form new molecules, such as CH 4 and C 2 H x , although this is dependent on the precise morphology of the surface. New molecules are also formed by subtraction of H-atoms from adsorbed radicals, leading to occasional formation of H 2 and C 2 H x molecules.

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Section: Resultssupporting

confidence: 87%

Section: Resultssupporting

confidence: 86%

Section: T H Imentioning

confidence: 99%

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Plasma Species Interacting with Nickel Surfaces: Toward an Atomic Scale Understanding of Plasma-Catalysis

et al. 2012

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“…Similar observations are also noticed in the case of Ni, where the H 2 adsorbed on the surface alters the surface energy of closed packed planes. 42 It was observed that the surface with lowest surface energy for Ni had changed from {111} to {100}. And also during an intermediate transition the surfaces were composed of both {111} and {100} surfaces, respectively.…”

Section: Resultsmentioning

confidence: 97%

Shape and structural motifs control of MgTi bimetallic nanoparticles using hydrogen and methane as trace impurities

et al. 2018

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In this work we report the influence of methane/hydrogen on the nucleation and formation of MgTi bimetallic nanoparticles (NPs) prepared by gas phase synthesis. We show that a diverse variety of structural motifs can be obtained from MgTi alloy, TiC/Mg/MgO, TiC/MgO and TiH/MgO core/shell NPs via synthesis using CH/H as a trace gas, and with good control of the final NP morphology and size distribution. Moreover, depending on the concentration of Ti and type of employed trace gas, the as prepared MgTi NPs can be tuned from truncated hexagonal pyramid to triangular and hexagonal platelet shapes. The shape of MgTi NPs is identified using detailed analysis from selected area electron diffraction (SAED) patterns and tomography (3D reconstruction based on a tilt series of Bright-Field transmission electron microscopy (TEM) micrographs). We observe the truncated hexagonal pyramid as a shape of MgTi alloy NPs in contrast to Mg NPs that show a hexagonal prismatic shape. Moreover, based on our experimental observations and generic geometrical model analysis, we also prove that the formation of the various structural motifs is based on a sequential growth mechanism instead of phase separation. One of the prime reasons for such mechanism is based on the inadequacy of Mg to nucleate without template in the synthesis condition. In addition, the shape of the TiC/TiH core, and the concentration of Mg have strong influence on the shape evolution of TiC/MgO and TiH/MgO NPs compared to TiC/Mg/MgO NPs, where the thermodynamics and growth rates of the Mg crystal planes dominate the final shape. Finally, it is demonstrated that the core shape of TiC and TiH is affected by the Mg/Ti target ratio (affecting the composition in the plasma), and the type of the trace gas employed. In the case of CH the TiC core forms a triangular platelet, while in the case of H the TiH core transforms into a hexagonal platelet. We elucidate the reason for the TiC/TiH core shape based on the presence of (i) defects, and (ii) hydrogen and carbon adsorption on {111} planes that alter the growth rates and surface facet stabilization.

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“…20) Another assumed candidate is the modification in the anisotropy of the surface free energy by the adsorption of hydrogen. 21) Its clarification, however, requires further investigation.…”

Section: Discussionmentioning

confidence: 99%

Hydrogen Effects on the Migration of Nanoscale Cavities in Iron

et al. 2021

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Accurate knowledge of the influence of hydrogen on the behavior of vacancies and vacancy clusters is crucial for understanding the mechanism of hydrogen embrittlement of α-iron and its alloys. Using in-situ transmission electron microscopy, we examined the effects of hydrogen on the behavior of nanoscale cavities under heating, by comparison between the behaviors of cavities without hydrogen produced upon high-energy electron irradiation and those with hydrogen produced upon electro-deposition. It is revealed that hydrogen promotes the migration of cavities, in contrast to a traditional notion.

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Effects of hydrogen adsorption on the surface-energy anisotropy of nickel

Cited by 19 publications

References 30 publications

Plasma Species Interacting with Nickel Surfaces: Toward an Atomic Scale Understanding of Plasma-Catalysis

Plasma Species Interacting with Nickel Surfaces: Toward an Atomic Scale Understanding of Plasma-Catalysis

Shape and structural motifs control of MgTi bimetallic nanoparticles using hydrogen and methane as trace impurities

Hydrogen Effects on the Migration of Nanoscale Cavities in Iron

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