scholarly journals An effective scheme to determine surface energy and its relation with adsorption energy

2021 ◽  
pp. 116895
Author(s):  
Bo Li ◽  
Xin Lia ◽  
Wang Gao ◽  
Qing Jiang
Keyword(s):  
Surface Energy ◽  
Adsorption Energy ◽  
Effective Scheme

scholarly journals An effective scheme to determine surface energy and its relation with adsorption energy

2020 ◽  
Author(s):  
Bo Li ◽  
Xin Li ◽  
Qing Jiang ◽  
Wang Gao
Keyword(s):  
Surface Energy ◽  
Adsorption Energy ◽  
Fluorite Structure ◽  
Rapid Screening ◽  
Quantitative Relation ◽  
Face Centered Cubic ◽  
Effective Scheme ◽  
Liquid Phases ◽  
Semiconductor Compounds ◽  
Face Centered

Abstract Surface energy is fundamental in controlling surface properties and surface-driven processes like heterogeneous catalysis, as adsorption energy is. It is thus crucial to establish an effective scheme to determine surface energy and its relation with adsorption energy. Herein, we propose a model to quantify the effects of materials’ intrinsic characteristics on the material-dependent property and anisotropy of surface energy, based on the period number and group number of bulk atoms, and the valence-electron number, electronegativity and coordination of surface atoms. Our scheme holds for elemental crystals in both solid and liquid phases, body-centered-tetragonal intermetallics, fluorite-structure intermetallics, face-centered-cubic intermetallics, Mg-based surface alloys and semiconductor compounds, which further identifies a quantitative relation between surface energy and adsorption energy and rationalizes the material-dependent error of first-principle methods in calculating the two quantities. This model is predictive with easily accessible parameters and thus allows the rapid screening of materials for targeted properties.

DFT STUDY OF METHYL (CH3) AND HYDROXYL (OH) ADSORPTION ON A GOLD (001) SURFACE

2019 ◽  
Vol 26 (05) ◽  
pp. 1850198 ◽  
Author(s):  
G. B. BOUKA-PIVOTEAU ◽  
M. N’DOLLO ◽  
B. R. MALONDA-BOUNGOU ◽  
B. MALOUMBI ◽  
P. S. MOUSSOUNDA ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Surface Energy ◽  
Dft Calculations ◽  
Adsorption Energy ◽  
Energy Surface ◽  
Geometrical Parameters ◽  
Oh Radical ◽  
Spin Polarized ◽  
Surface Dipole ◽  
Adsorption Energies

We used the DACAPO code with the GGA-PW91 approximation to study the adsorption of methyl (CH3) and hydroxyl (OH) for four- and five-layer gold (Au) (001) slabs. We have determined for each species the best binding site, adsorption energy, the change in the work function, surface energy, surface dipole moment, geometrical parameters and projected density of states (PDOS). We performed spin-unpolarized and spin-polarized DFT calculations for free and adsorbed CH3 and OH species. The most important point is that the spin polarization diminishes the adsorption energies but does not change the geometrical parameters. For the CH3 species, only the top site was found to be stable for different coverages. We found that during the optimization phase, the hollow and bridge sites were found to be unstable. In both cases the CH3 species moves toward the top site. We observe that the adsorption energy decreases when increasing the coverage. However, the OH species was stable in all investigated sites (top, bridge and hollow). We notice that the adsorption energy is dependent on the number of slab layers and the bridge is the best site in adsorption energy. The analysis of the calculated O PDOS of OH radical shows a mixing between the O orbitals and the Au bands.

Effect of Cu Alloying on S Poisoning of Ni Surfaces and Nanoparticle Morphologies Using Ab-Initio Thermodynamics Calculations

2015 ◽  
Vol 15 (10) ◽  
pp. 8205-8210 ◽  
Author(s):  
Ji-Su Kim ◽  
Byung-Kook Kim ◽  
Yeong-Cheol Kim
Keyword(s):  
Surface Energy ◽  
Ab Initio ◽  
Adsorption Energy ◽  
Chemical Potential ◽  
Segregation Energy ◽  
Nanoparticle Morphology ◽  
Pure Cu ◽  
Nicu Alloys

We investigated the effect of Cu alloying on S poisoning of Ni surfaces and nanoparticle morphologies using ab-initio thermodynamics calculations. Based on the Cu segregation energy and the S adsorption energy, the surface energy and nanoparticle morphology of pure Ni, pure Cu, and NiCu alloys were evaluated as functions of the chemical potential of S and the surface orientations of (100), (110), and (111). The constructed nanoparticle morphology was varied as a function of chemical potential of S. We find that the Cu added to Ni for NiCu alloys is strongly segregated into the top surface, and increases the S tolerance of the NiCu nanoparticles.

Surface energy and adsorption energy distribution measurements on some carbon blacks

Carbon ◽  
1991 ◽  
Vol 29 (8) ◽  
pp. 1135-1143 ◽  
Author(s):  
Eugène Papirer ◽  
Sheng Li ◽  
Henri Balard ◽  
Jacek Jagiello
Keyword(s):  
Surface Energy ◽  
Energy Distribution ◽  
Adsorption Energy ◽  
Carbon Blacks ◽  
Adsorption Energy Distribution

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

Influence of Fiber Surface Energy on Mechanical Properties of Sisal Fiber - Bio Based Epoxy Composites

2019 ◽  
Vol 35 (4) ◽  
pp. 485-496
Author(s):  
S. RAJKUMAR ◽  
◽  
R. JOSEPH BENSINGH ◽  
M. ABDUL KADER ◽  
SANJAY K NAYAK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Energy ◽  
Fiber Surface ◽  
Epoxy Composites ◽  
Sisal Fiber

DEVELOPMENT OF AN EFFECTIVE SCHEME FOR THE ENRICHMENT OF COPPER-MOLYBDENUM ORES USING NEW REAGENTS-COLLECTORS

2020 ◽  
Vol 20 (10) ◽  
Author(s):  
Inoyat Umarova ◽  
Jamshid Ibragimov ◽  
Sarvinoz Kholmatova ◽  
Dilmurod Makhmarejabov
Keyword(s):  
Effective Scheme

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

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