scholarly journals First-Principle Study of Co-Adsorption Behavior of H2O and O2 on δ-Pu (100) Surface

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1098
Author(s):  
Guoliang Wang ◽  
Zhaoyang Zhao ◽  
Pengfei Zhai ◽  
Xudan Chen ◽  
Yefei Li
Keyword(s):  
Surface Layer ◽  
Energy Analysis ◽  
Co Adsorption ◽  
Adsorption Behavior ◽  
First Principle ◽  
Surface Corrosion ◽  
Preferential Adsorption ◽  
Density Analysis ◽  
Charge Analysis ◽  
Bader Charge Analysis

The surface corrosion of plutonium in air is mainly the result of the interaction with O2 and H2O in air. In this paper, the co-adsorption behavior of O2 and H2O on a δ-Pu (100) surface is studied by the first-principle method. Two different cases of preferential adsorption of H2O and O2 are considered, respectively. Bader charge analysis and adsorption energy analysis are carried out on all stable adsorption configurations, and the most stable adsorption configurations are found under the two conditions. The results of differential charge density analysis, the density of states analysis and Crystal Orbital Hamilton Populations (COHP) analysis show that the two molecules can promote each other’s adsorption behavior, which leads to the strength and stability of co-adsorption being far greater than that of single adsorption. In the co-adsorption configuration, O atoms preferentially interact with Pu atoms in the surface layer, and the essence is that the 2s and 2p orbitals of O overlap and hybridize with the 6p and 6d orbitals of Pu. H atoms mainly form O–H bonds with O atoms and hardly interact with Pu atoms on the surface layer.

scholarly journals Toxic Gases on β12 Borophene: the Selective Adsorption

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Ta Thi Luong ◽  
Pham Trong Lam ◽  
Dinh Van An
Keyword(s):  
Selective Adsorption ◽  
Electronic Devices ◽  
First Principle ◽  
First Principle Calculations ◽  
Toxic Gases ◽  
Charge Analysis ◽  
Gas Molecules ◽  
Selective Adsorbent ◽  
And Diffusion ◽  
Bader Charge Analysis

Borophene, a new member of the 2D material family, was proven theoretically and empirically in many recent studies that it has a unique structure and promising properties applied in batteries and electronic devices. In this work, the adsorbability of β12 – borophene towards some main poisonous gases was investigated. Herein, first-principle calculations were employed to obtain the adsorption configurations, adsorption energy of CO, NO, CO2, NH3, and NO2 on b12 – borophene by using three van der Waals correlation functionals: revPBE-vdW, optPBE-vdW, and vdW-DF2. Also, the most stable configurations and diffusion possibilities of the gas molecules on the surface of b12 – borophene were determined visually by using Computational DFT-based Nanoscope. The nature of bonding and interaction between gas molecules and b12 – borophene were disclosed by using the density of states analysis and Bader charge analysis. Remarkably, borophene exhibits as a highly selective adsorbent when having great interactions with NOx gases outweigh the others.

First Principles Investigation of the Stability and the Chemical Behavior of Hydrogen in ThCoH4

2011 ◽  
Vol 66 (3) ◽  
pp. 269-274
Author(s):  
Samir F. Matar
Keyword(s):  
Negative Charge ◽  
Geometry Optimization ◽  
Full Geometry Optimization ◽  
Intermetallic Matrix ◽  
Charge Analysis ◽  
The Stability ◽  
The One ◽  
Site Selective ◽  
Bader Charge Analysis ◽  
Positively Charged

We address the changes in the electronic structure brought by the insertion of hydrogen into ThCo leading to the experimentally observed ThCoH4. Full geometry optimization positions the hydrogen in three sites stabilized in the expanded intermetallic matrix. From a Bader charge analysis, hydrogen is found to be in a narrow iono-covalent (~−0.6) to covalent (~−0.3) bonding which should enable site-selective desorption. The overall chemical picture shows a positively charged Thδ+ with the negative charge redistributed over a complex anion {CoH4}δ− with δ~1.8. Nevertheless this charge transfer remains far from the one in the more ionic hydridocobaltate anion CoH54− in Mg2CoH5, due to the largely electropositive character of Mg.

Adsorption and Co‐adsorption of Chlorine and Water‐Chlorine Complexes on Au(111) Surface: First‐Principle DFT Study

2021 ◽  
Author(s):  
De-Yin Wu ◽  
Yuan-Hui Xiao ◽  
Jia Liu ◽  
Jian-De Lin ◽  
Huan-Huan Yu ◽  
...  
Keyword(s):  
Co Adsorption ◽  
Dft Study ◽  
First Principle

Experimental and computational investigations of TiIrB: a new ternary boride with Ti1+x Rh2−x+y Ir3−y B3-type structure

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jan P. Scheifers ◽  
Kate A. Gibson ◽  
Boniface P. T. Fokwa
Keyword(s):  
Density Functional ◽  
Ternary Phase ◽  
Structure Type ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Arc Melting ◽  
Ternary Boride ◽  
Charge Analysis ◽  
First Time ◽  
Bader Charge Analysis

Abstract A new ternary phase, TiIrB, was synthesized by arc-melting of the elements and characterized by powder X-ray diffraction. The compound crystallizes in the orthorhombic Ti1+x Rh2−x+y Ir3−y B3 structure type, space group Pbam (no. 55) with the lattice parameters a = 8.655(2), b = 15.020(2), and c = 3.2271(4) Å. Density Functional Theory (DFT) calculations were carried out to understand the electronic structure, including a Bader charge analysis. The charge distribution of TiIrB in the Ti1+x Rh2−x+y Ir3−y B3-type phase has been evaluated for the first time, and the results indicate that more electron density is transferred to the boron atoms in the zigzag B4 units than to isolated boron atoms.

Analysis of Surface Layer Defects on Carburized Steel Component after Alkaline Blackening

2017 ◽  
Vol 891 ◽  
pp. 274-277
Author(s):  
Pavel Gejdoš ◽  
Lenka Klakurková ◽  
Martin Juliš ◽  
Miroslava Horynová ◽  
Michaela Remešová ◽  
...  
Keyword(s):  
Surface Layer ◽  
Surface Defects ◽  
Technological Parameters ◽  
Treatment Technology ◽  
Steel Component ◽  
Surface Corrosion ◽  
Carburized Steel ◽  
Matte Surface ◽  
Microstructure Of The Material

Alkaline blackening is one of the most popular surface treatment technology of components with the requirement for higher surface corrosion resistance, increased hardness, and the decorative appearance.This contribution deals with the appearance of surface defects on carburized steel components after the process of alkaline blackening, which appeared to be red shiny stains on an otherwise black matte surface of the component. The occurrence of defects on surface was observed several days after the alkaline blackening process. By means of metallographic methods, direct connection between surface defects and the microstructure of the material was found.Contribution further deals with the influence of microstructure and technological parameters on the quality of the final surface layer of the components.

Cleaning and Reflow of Pb-Sn C4 Solder Bumps

1995 ◽  
Vol 117 (4) ◽  
pp. 281-287 ◽  
Author(s):  
Caroline S. Lee ◽  
Doug C. Crafts ◽  
T. W. Eagar
Keyword(s):  
Growth Rate ◽  
Surface Layer ◽  
Reaction Rate ◽  
Diffusion Rate ◽  
Primary Component ◽  
Corrosion Layer ◽  
Dense Layer ◽  
Surface Corrosion ◽  
Solder Bumps ◽  
Electroplating Process

The Pb/Sn electroplating process for C4 technology requires the ability to etch Ball Limiting Metallurgy (BLM) in the presence of the Pb/Sn bumps. Upon etching, a surface corrosion layer is formed and an appropriate cleaning acid must be used to remove this layer prior to solder reflow of the bumps. It was found that the morphology of the surface layer formed upon etching on the Pb/Sn solder bumps is critically dependent on the concentration of the etchant. Using a gravimetric test, XPS and AES analysis, PbO containing small amounts of Sn and S, was identified to be the primary component of the surface. The thickness morphology, composition and the growth rate of the layer are critically dependent on the sulfur from the etchant. In H2O2-rich solutions, the surface appears to be loosely packed and the growth rate on the surface of the bump was found to be reaction-rate limited; whereas, in H2SO4-rich solutions, the diffusion rate is the controlling step informing the surface layer on the solder bumps, thus producing a thin and dense layer.

CO Adsorption Behavior of Cu/SiO2, Co/SiO2, and CuCo/SiO2 Catalysts Studied by in Situ DRIFTS

2012 ◽  
Vol 116 (14) ◽  
pp. 7931-7939 ◽  
Author(s):  
Miranda L. Smith ◽  
Nitin Kumar ◽  
James J. Spivey
Keyword(s):  
Co Adsorption ◽  
Adsorption Behavior ◽  
In Situ Drifts
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