scholarly journals Theoretical Investigation on Rare Earth Elements of Y, Nd and La Atoms’ Adsorption on the Kaolinite (001) and (001¯) Surfaces

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 856
Author(s):  
Jian Zhao ◽  
Zheng Wang ◽  
Wei Gao ◽  
Yi-Fei Wang ◽  
Bo-Wen Huang
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Adsorption Energy ◽  
Density Functional ◽  
Adsorption Mechanism ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Surface Sites ◽  
Before And After ◽  
Adsorption Technology

With the growing demand of rare earth elements, the recovery of rare earth elements is a major issue for researchers in related fields. Adsorption technology is one of the most effective and popular recovery methods. Therefore, the adsorption mechanism of Yttrium (Y), Neodymium (Nd), and Lanthanum (La) atoms on the kaolinite (001) and (001¯) surfaces was examined by density functional theory (DFT). The most stable adsorption sites on the kaolinite (001) surface for Y atoms was the bridge site, and the hollow site was the most favorable adsorption site for Nd and La atoms with high adsorption energy. However, the adsorption energies of kaolinite (001¯) surface sites for Y, Nd, and La atoms were much lower than the (001) surface sites, indicating that the adsorption capability of the hydroxylated (001) surface is stronger. The effects of coverage on adsorption position, energy, and structures were entirely investigated on top, bridge, and hollow sites of the kaolinite (001) surface from 0.11 to 1.0 monolayers (ML). The adsorption energy of Y, Nd, and La atoms on three kinds of sites increased with increasing of the coverage implied the stronger capability of surface adsorption. The recovery capability of kaolinite for the rare earth atoms was in the order of La > Nd > Y. The changes in the atomic structure, charge density, and electron density of states for Y, Nd, and La/kaolinite (001) before and after adsorption were also analyzed in depth.

Adsorption of rare-earth atoms onl silicon carbide nanotube: a density-functional study

2014 ◽  
Vol 28 (19) ◽  
pp. 1450154
Author(s):  
Zhiwei An ◽  
Jiang Shen
Keyword(s):  
Silicon Carbide ◽  
Rare Earth ◽  
Density Functional ◽  
Binding Energies ◽  
Functional Study ◽  
Hollow Site ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Metal Atoms ◽  
Silicon Carbide Nanotube

In this paper, we investigate the adsorption of a series of rare-earth (RE) metal atoms ( La , Pr , Nd , Sm and Eu ) on the pristine zigzag (8, 0) silicon carbide nanotube ( SiCNT ) using density functional theory (DFT). Main focuses are placed on the stable adsorption sites, the corresponding binding energies, and the modified electronic properties of the SiC nanotubes due to the adsorbates. A single RE atom prefers to adsorb strongly at the hollow site with relatively high binding energy (larger than 1.0 eV). Due to the rolling effect of single-walled SiCNTs , the inside configurations are more stable than the outside ones. For RE-adsorbed systems, the adsorption of metal atoms induces certain impurity states within the band gap of the pristine SiCNT . Furthermore, we analyze there exists hybridizations between RE-5d, 6s, C -2p and Si -3p orbitals for the RE atom adsorption on the SiCNTs .

Molecular Oxygen Adsorbed on Gallium Doped Graphene: A First-Principles Study

2017 ◽  
Vol 890 ◽  
pp. 117-120
Author(s):  
Seba Sara Varghese ◽  
Sundaram Swaminathan ◽  
Krishna Kumar Singh ◽  
Vikas Mittal
Keyword(s):  
Electronic Properties ◽  
Molecular Oxygen ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Strong Interactions ◽  
Functional Theory ◽  
Before And After ◽  
Doped Graphene

The adsorption of molecular oxygen on gallium doped graphene sheet is investigated using first-principles density functional theory calculations. The adsorption energy of O2 on gallium doped graphene is calculated after determining the energetically favourable adsorption configuration. The change in the electronic properties of gallium doped graphene after O2 adsorption is also determined to understand the nature their interactions. The results show that gallium doped graphene has large adsorption energy and small binding distance, which correspond to chemical adsorption. The calculated band structure and density of states plots of gallium doped graphene before and after adsorption show dramatic changes in the electronic properties due to the strong interactions of gallium doped graphene with adsorbed O2 molecule. These results indicate that gallium doped graphene is highly reactive to molecular oxygen and hence not a suitable choice for harmful gas detection in the presence of O2.

scholarly journals Temperature-Dependent Generalized Planar Fault Energy and Twinnability of Mg Microalloyed with Er, Ho, Dy, Tb, and Gd: First-Principles Study

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Lili Liu ◽  
Yelu He ◽  
Dingxing Liu ◽  
Xiaozhi Wu ◽  
Rui Wang
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Density Functional ◽  
Atomic Radius ◽  
Temperature Dependent ◽  
Functional Theory ◽  
Planar Fault ◽  
Change Trend ◽  
Underlying Mechanisms ◽  
Increasing Temperature

The generalized planar fault energies, Rice criterion ductility, and twinnability of pure Mg and Mg-RE (RE = Er, Ho, Dy, Tb, and Gd) alloys at different temperature have been investigated using density functional theory. It is shown that all the fault energies and twinnability in the same materials decrease with increasing temperature. However, the ductility has the opposite change trend. On the other hand, alloying rare earth elements will generally decrease the fault energies and increase the ductility and twinnability of Mg at different temperature. It is interesting to note that alloying larger atomic radius will enhance the ductility of Mg more easily and alloying smaller radius will make twinning tendency of Mg more easily. Finally, the electron structure further reveals the underlying mechanisms for the reduction of fault energies with the addition of rare earth elements.

scholarly journals Density Functional Theory Study of Hydrogen Adsorption on Pt Pd/γ-Al2O3 Surface

2021 ◽  
Vol 2097 (1) ◽  
pp. 012020
Author(s):  
Liang Zhang ◽  
Jia Li ◽  
Yong Chen ◽  
Cheng Zeng ◽  
Wu Kang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Energy Gap ◽  
Solid Catalyst ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Lower Energy Level ◽  
Catalytic Hydrogen

Abstract At present passive hydrogen recombiners (PAR) are used to prevent hydrogen explosion. Hydrogen removal catalyst is the core component of PAR. The adsorption of hydrogen on the solid catalyst surface is the premise of catalytic hydrogen removal and is of great significance for deeper understanding of hydrogen removal mechanism. The adsorption behavior of H2-Pt Pd/γ-Al2O3 system has been studied by using density functional theory and periodic slab model. The results of different adsorption sites indicate the adsorption energy of top site is highest, which is -1.2584eV. Higher adsorption energy means stronger interaction between H2 and catalyst substrate, which elongates H-H bond and increases the negative charge on H2. With increasing doping content of Pd, the adsorption energy of substrate decreases gradually. The adsorption energy absolute value of Pt4/γ-Al2O3 is highest and its H-H bond is longest, arriving at 0.0967nm. After adsorbed on substrate, the energy gap of H2 decreases drastically with the lowest energy gap of H2-Pt4/γ-Al2O3 that is 0.5197eV, and the peaks of density of state pattern move to lower energy level. This is because that the d orbital of Pt/Pd atoms interacts with the τ* anti-bond orbital of H2 strongly, transferring electrons to the τ* anti-bond orbital of H2. Doping Pd increases the energy gap of molecule orbital.

scholarly journals Prediction of 2D ferromagnetism and monovalent europium ions in the EuBr/graphene heterojunctions

2021 ◽  
Author(s):  
Haoyi Tan ◽  
Guangcun Shan ◽  
Gianfranco Pacchioni
Keyword(s):  
Density Functional Theory ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Valence States ◽  
Magnetic Modification ◽  
Modification Of Materials ◽  
The Rare Earth

Europium, one of the rare earth elements, exhibits +2 and +3 valence states and has been widely used for magnetic modification of materials. Based on density functional theory calculations, we...

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