scholarly journals Density functional theory insights into the bonding of CH3OH and CH3O with Ir(111) surface

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Thong Le Minh Pham ◽  
Khoa Thanh Phung ◽  
Thang Viet Ho ◽  
Thi Anh Le ◽  
An Thai Thi Nguyen
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Density Functional ◽  
Molecular Characteristics ◽  
Functional Theory ◽  
Adsorption Structure ◽  
The Density Functional Theory ◽  
Production Of Hydrogen ◽  
Charge Analysis ◽  
The Difference

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.

Density Functional Theory Calculations of Arsenic(III) Structures on Perfect TiO2 Anatase (1 0 1) Surface

2011 ◽  
Vol 233-235 ◽  
pp. 491-494 ◽  
Author(s):  
Lin Yu ◽  
Yue Liu ◽  
Zhi Gang Wei ◽  
Gui Qiang Diao ◽  
Ming Sun ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Density Functional ◽  
Function Method ◽  
Photocatalytic Oxidation ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Low Concentrations ◽  
The Density Functional Theory ◽  
The World

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.

Density Functional Theory Calculations of Arsenic(V) Structures on Perfect TiO2 Anatase (1 0 1) 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 ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Density Functional ◽  
Function Method ◽  
Photocatalytic Oxidation ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Low Concentrations ◽  
The Density Functional Theory ◽  
The World

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.

Density functional theory study of acrolein adsorption on graphyne

2015 ◽  
Vol 93 (11) ◽  
pp. 1261-1265
Author(s):  
A.R. Karami
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Adsorption Energy ◽  
Density Functional ◽  
Mulliken Charge ◽  
Density Functional Theory Study ◽  
Donor Molecule ◽  
Functional Theory ◽  
Charge Analysis ◽  
Semiconducting Property

We have used density functional theory to study the effect of acrolein adsorption on the electronic properties of graphyne. It is found that the acrolein molecule is physisorbed on graphyne sheets with small adsorption energy and large adsorption distance. Mulliken charge analysis indicates that charge is transferred from the acrolein molecule to the graphyne sheets. In the presence of this charge donor molecule, α- and β-graphyne with semimetallic properties and γ-graphyne with semiconducting property become n-type semiconductors. The sensitivity of the electronic properties of graphyne to the presence of acrolein indicates that graphyne sheets are appropriate materials to use as a sensor for acrolein detection.

scholarly journals DFT Analysis of NO Adsorption on the Undoped and Ce-Doped LaCoO3 (011) Surface

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1379 ◽  
Author(s):  
Xiaochen Li ◽  
Hongwei Gao
Keyword(s):  
Adsorption Energy ◽  
Density Functional ◽  
Adsorption Process ◽  
Dft Method ◽  
Adsorption Site ◽  
No Adsorption ◽  
Functional Theory ◽  
Adsorption Structure ◽  
Preferential Adsorption ◽  
The Density Functional Theory

Using the density functional theory (DFT) method, we investigated the adsorption of NO on the undoped and Ce-doped LaCoO3 (011) surface. According to our calculations, the best adsorption site is not changed after Ce doping. When the NO molecule is adsorbed on the perfect LaO-terminated LaCoO3 (011) surface, the most stable adsorption site is hollow-top, which corresponds to the hollow-NO configuration in our study. After the substitution of La with Ce, the adsorption energy of hollow-NO configuration is increased. For the perfect CoO2-terminated LaCoO3 (011) surface, it is found that Co-NO configuration is the preferential adsorption structure. Its adsorption energy can also be enhanced after Ce doping. When NO molecule is adsorbed on the undoped and Ce-doped LaO-terminated LaCoO3 (011) surface with hollow-NO configuration, it serves as the acceptor and electrons transfer from the surface to it in the adsorption process. On the contrary, for the Co-NO configuration of undoped and Ce-doped CoO2-terminated LaCoO3 (011) surface, NO molecule becomes the donor and loses electrons to the surface.

Density Functional Theory Study of the Adsorption of Metal Adatoms on Graphene

2021 ◽  
Vol 1016 ◽  
pp. 1863-1868
Author(s):  
Norio Nunomura ◽  
Jun Yamashita ◽  
Satoshi Sunada
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Copper Atom ◽  
First Principles ◽  
Density Functional ◽  
Aluminum Atom ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Nanocarbon Materials ◽  
The Difference

In this study, we investigated the influence of the interaction between graphene and other materials as a basis for controlling the electronic structure of nanocarbon materials. First-principles calculations based on density functional theory (DFT) were performed on the optimized structure, adsorption energies and electronic states when copper and aluminum atoms were placed on graphene. As a result, we found that copper and aluminum are stable at the bridge and the hollow site, respectively. It was found that the adsorption energy of aluminum atom on graphene is larger than that of copper atom. It is considered that the difference in adsorption energy is caused by the difference in the dominant electron orbitals of the copper atom and the aluminum atom.

Novel H2S multifunctional sensing materials; Cu or Ag-decorated (4,4)SWSiC nanotubes

2021 ◽  
Author(s):  
Rosa Safaiee ◽  
M. M. Golshan ◽  
M. Khalifeh
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Density Functional ◽  
Functional Theory ◽  
The Density Functional Theory

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...

scholarly journals Density Functional Theory Study of Metal and Metal-Oxide Nucleation and Growth on the Anatase TiO2(101) Surface

Computation ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 125
Author(s):  
Leila Kalantari ◽  
Fabien Tran ◽  
Peter Blaha
Keyword(s):  
Density Functional Theory ◽  
Metal Oxide ◽  
Adsorption Energy ◽  
Density Functional ◽  
Magnetic Moments ◽  
Experimental Studies ◽  
Anatase Tio2 ◽  
Functional Theory ◽  
Transition Electron Microscopy ◽  
Production Of Hydrogen

Experimental studies have shown the possible production of hydrogen through photocatalytic water splitting using metal oxide (MOy) nanoparticles attached to an anatase TiO2 surface. In this work, we performed density functional theory (DFT) calculations to provide a detailed description of the stability and geometry of MxOy clusters M = Cu, Ni, Co, Fe and Mn, x = 1–5, and y = 0–5 on the anatase TiO2(101) surface. It is found that unsaturated 2-fold-coordinated O-sites may serve as nucleation centers for the growth of metal clusters. The formation energy of Ni-containing clusters on the anatase surface is larger than for other M clusters. In addition, the Nin adsorption energy increases with cluster size n, which makes the formation of bigger Ni clusters plausible as confirmed by transition electron microscopy images. Another particularity for Ni-containing clusters is that the adsorption energy per atom gets larger when the O-content is reduced, while for other M atoms it remains almost constant or, as for Mn, even decreases. This trend is in line with experimental results. Also provided is a discussion of the oxidation states of M5Oy clusters based on their magnetic moments and Bader charges and their possible reduction with oxygen depletion.

scholarly journals Competitive Adsorption of H2O and SO2 on Catalytic Platinum Surfaces: a Density Functional Theory Study

2021 ◽  
Vol 74 ◽  
Author(s):  
Marietjie J. Ungerer ◽  
David Santos-Carballal ◽  
Cornelia G.C.E. van Sittert ◽  
Nora H. de Leeuw
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Sulphur Dioxide ◽  
Density Functional ◽  
Competitive Adsorption ◽  
Hydrogen Adsorption ◽  
Surface Reactivity ◽  
Functional Theory ◽  
Sulphur Poisoning ◽  
Production Of Hydrogen

ABSTRACT Platinum has been widely used as the catalyst of choice for the production of hydrogen in the hybrid sulphur (HyS) cycle. In this cycle, water (H2O) and sulphur dioxide (SO2) react to form sulphuric acid and hydrogen. However, the surface reactivity of platinum towards H2O and SO2 is not yet fully understood, especially considering the competitive adsorption that may occur on the surface. In this study, we have carried out density functional theory calculations with long-range dispersion corrections [DFT-D3-(BJ)] to investigate the competitive effect of both H2O and SO2 on the Pt (001), (011) and (111) surfaces. Comparing the adsorption of a single H2O molecule on the various Pt surfaces, it was found that the lowest adsorption energy (Eads = -1.758 eV) was obtained for the dissociative adsorption of H2O on the (001) surface, followed by the molecular adsorption on the (011) surface (Eads = -0.699 eV) and (111) surface (Eads = -0.464 eV). For the molecular SO2 adsorption, the trend was similar, with the lowest adsorption energy (Eads = -2.471 eV) obtained on the (001) surface, followed by the (011) surface (Eads = -2.390 eV) and (111) surface (Eads = -1.852 eV). During competitive adsorption by H2O and SO2, the SO2 molecule will therefore preferentially adsorb onto the Pt surface. If the concentration of SO2 increases, self-reaction between two neighbouring SO2 molecules may occur, leading to the formation of sulphur monoxide (SO) and -trioxide (SO3) on the surface, which could lead to sulphur poisoning of the Pt catalytic surface. Keywords: Platinum, water, sulphur dioxide, hydrogen, adsorption, density functional theory.

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