Adsorption energy of the As atom on the Pd(111) surface according to the density functional theory data

2011 ◽  
Vol 52 (6) ◽  
pp. 1098-1101 ◽  
Author(s):  
S. E. Malykhin ◽  
M. Yu. Burylin ◽  
S. Yu. Burylin ◽  
I. L. Zil’berberg
2011 ◽  
Vol 233-235 ◽  
pp. 491-494 ◽  
Author(s):  
Lin Yu ◽  
Yue Liu ◽  
Zhi Gang Wei ◽  
Gui Qiang Diao ◽  
Ming Sun ◽  
...  

There are many areas in the world where the ground water has been contaminated by arsenic. One process to purify the water is to use TiO2 to adsorb the arsenic. As the TiO2 surface can be cleaned and reused, it has a promising potential as a water purifier. In this paper, the plane-wave function method, based on the density functional theory, has been used to calculate the structures of arsenic(III) on a perfect TiO2 anatase (1 0 1) surface. All the arsenic(III) solution species such as H3AsO3, H2AsO3-1, HAsO3-2 and AsO3-3 are put onto the surface with many different possible structures to obtain the adsorption energy. Based on the adsorption energy, the bidentate binuclear (BB) adsorption configurations of arsenic(III) on the surface are more favorable at low concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. The models and results fit well with published experimental results. The results and conclusions will be of benefit to further research on arsenite adsorption and its photocatalytic oxidation on a TiO2 surface.


2011 ◽  
Vol 233-235 ◽  
pp. 495-498 ◽  
Author(s):  
Zhi Gang Wei ◽  
Yan Di Zou ◽  
Hai Xia Zeng ◽  
Xue Chun Zhong ◽  
Zhen Jun Cheng ◽  
...  

There are many areas in the world where the ground water has been contaminated by arsenic. One process to purify the water is to use TiO2 to adsorb the arsenic. As the TiO2 surface can be cleaned and reused, it has a promising potential as a water purifier. In this paper, the plane-wave function method, based on the density functional theory, has been used to calculate the structures of arsenic(III) on a perfect TiO2 anatase (1 0 1) surface. All the arsenic(III) solution species such as H3AsO3, H2AsO3-1, HAsO3-2 and AsO3-3 are put onto the surface with many different possible structures to obtain the adsorption energy. Based on the adsorption energy, the bidentate binuclear (BB) adsorption configurations of arsenic(III) on the surface are more favorable at low concentrations, whereas BB form and monodentate mononuclear (MM) form may coexist at higher concentrations. The models and results fit well with published experimental results. The results and conclusions will be of benefit to further research on arsenite adsorption and its photocatalytic oxidation on a TiO2 surface.


Author(s):  
Rosa Safaiee ◽  
M. M. Golshan ◽  
M. Khalifeh

The density functional theory in Grimme’s D3 method is employed to study the H2S sensing ability of pristine, as well as Cu or Ag decorated, (4,4)SWSiCNT. The adsorption energy, most...


2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Thong Le Minh Pham ◽  
Khoa Thanh Phung ◽  
Thang Viet Ho ◽  
Thi Anh Le ◽  
An Thai Thi Nguyen

Introduction: Understanding the adsorption characteristics of CH3OH and CH3O on the noble metal surfaces is essential for designing better catalysts for the on-board production of hydrogen from CH3OH. This study aims to provide insights into the adsorption behavior of these molecules on Ir(111) surface. Methods: The adsorption structure, the adsorption energy, and the bonding mechanism of CH3OH and CH3O with Ir(111) surface were investigated by means of the density functional theory (DFT) calculations and the Bader charge analysis. Results: The DFT results show that the adsorption of CH3OH and CH3O is driven by the formation of Ir–O bond at the top site of the surface by the overlap of O-2p and Ir-5d orbitals. The overlap of these orbitals is greater in the absorption of CH3O, resulting in stronger adsorption energy of CH3O (2.23 eV vs. 0.32 eV). In agreement with the adsorption strength, the charge transfer from CH3O to the surface is significantly larger than from CH3OH (0.386 e vs. 0.073 e). Conclusion: Although driven by the same adsorption bond, the difference in the molecular characteristics leads to a marked difference in the absorption strength of CH3OH and CH3O on Ir(111) surface.


Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1292
Author(s):  
Haipei Zhang ◽  
Bo Li ◽  
Yonggang Wei ◽  
Hua Wang

Based on the density functional theory, the geometric structure, adsorption energy and density of states of H2/α-Fe2O3 (001) system and (H2 + Ni)/α-Fe2O3 (001) system were determined. The results showed that the absolute value of adsorption energy between H2 molecule and α-Fe2O3 (001) surface and the bond length of H2 molecule were increased by the presence of Ni atom. The presence of Ni atom promotes the adsorption of H2 molecule on α-Fe2O3 (001) surface. Reduction behavior of iron and nickel oxides in H2 atmosphere was determined by thermogravimetric analysis. The samples included Fe2O3, Fe2O3-NiO and Fe2O3-Ni systems. The effect of Ni and NiO on the reduction behavior of Fe2O3 was investigated. The ease of reduction within the following three systems decreases sequentially: Fe2O3-Ni > Fe2O3-NiO > Fe2O3. The activation energy of Fe2O3-Ni, Fe2O3-NiO and Fe2O3 systems at two temperature stages (viz. < 400 °C and > 400 °C) were 172 kJ·mol−1, 197 kJ·mol−1 and 263 kJ·mol−1 respectively.


Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...


2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.


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