scholarly journals First-Principles Investigation of CO Adsorption on h-Fe7C3 Catalyst

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 635
Author(s):  
Jinzhe Fu ◽  
Deshuai Sun ◽  
Zhaojun Chen ◽  
Jian Zhang ◽  
Hui Du
Keyword(s):  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Co Adsorption ◽  
Active Phase ◽  
Crystal Plane ◽  
Fischer Tropsch ◽  
Medium Temperature ◽  
Functional Theory ◽  
Miller Index

h-Fe7C3 is considered as the main active phase of medium-temperature Fe-based Fischer–Tropsch catalysts. Basic theoretical guidance for the design and preparation of Fe-based Fischer–Tropsch catalysts can be obtained by studying the adsorption and activation behavior of CO on h-Fe7C3. In this paper, the first-principles method based on density functional theory is used to study the crystal structure properties of h-Fe7C3 and the adsorption and activation CO on its low Miller index surfaces ( 1 1 ¯ 0 ) , ( 1 1 ¯ 1 ) , ( 101 ) , ( 1 1 ¯ 1 ¯ ) and ( 001 ) . It was found that the low Miller index crystal plane of h-Fe7C3 crystal has multiple equivalent crystal planes and that the maximum adsorption energy of CO at the 3F2 point of the ( 1 1 ¯ 1 ) plane is −2.50 eV, indicating that h-Fe7C3 has a better CO adsorption performance. In addition, the defects generated at the truncated position of the h-Fe7C3 crystal plane have a great impact on the adsorption energy of CO on its surface, that is, the adsorption energy of CO on Fe atoms with C vacancies is higher. The activity of CO after adsorption is greatly affected by the adsorption configuration and less affected by the adsorption energy. The higher the coordination number of Fe atoms after adsorption, the higher the CO activity. At the same time, it was found that the bonding of O and Fe atoms is conducive to the activation of CO.

Suppression by Pt of CO adsorption and dissociation and methane formation on Fe5C2(100) surfaces

2018 ◽  
Vol 20 (39) ◽  
pp. 25246-25255 ◽  
Author(s):  
Yurong He ◽  
Peng Zhao ◽  
Jinjia Liu ◽  
Wenping Guo ◽  
Yong Yang ◽  
...  
Keyword(s):  
Density Functional ◽  
Co Adsorption ◽  
Density Functional Theory Method ◽  
Methane Formation ◽  
Fischer Tropsch ◽  
Functional Theory ◽  
Spin Polarized ◽  
Synthesis Catalysts ◽  
Iron Based ◽  
Adsorption And Dissociation

To understand the chemical origin of platinum promotion effects on iron based Fischer–Tropsch synthesis catalysts, the effects of Pt on CO adsorption and dissociation as well as surface carbon hydrogenation on the Fe5C2(100) facet with different surface C* contents have been studied using the spin-polarized density functional theory method.

scholarly journals First Principles Study of Gas Molecules Adsorption on Monolayered β-SnSe

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 390 ◽  
Author(s):  
Tianhan Liu ◽  
Hongbo Qin ◽  
Daoguo Yang ◽  
Guoqi Zhang
Keyword(s):  
Gas Sensors ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Adsorption Properties ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Β Phase ◽  
Physical Sensor ◽  
Gas Molecules

For the purpose of exploring the application of two-dimensional (2D) material in the field of gas sensors, the adsorption properties of gas molecules, CO, CO2, CH2O, O2, NO2, and SO2 on the surface of monolayered tin selenium in β phase (β-SnSe) has been researched by first principles calculation based on density functional theory (DFT). The results indicate that β-SnSe sheet presents weak physisorption for CO and CO2 molecules with small adsorption energy and charge transfers, which show that a β-SnSe sheet is not suitable for sensing CO and CO2. The adsorption behavior of CH2O molecules adsorbed on a β-SnSe monolayer is stronger than that of CO and CO2, revealing that the β-SnSe layer can be applied to detect CH2O as physical sensor. Additionally, O2, NO2, and SO2 are chemically adsorbed on a β-SnSe monolayer with moderate adsorption energy and considerable charge transfers. All related calculations reveal that β-SnSe has a potential application in detecting and catalyzing O2, NO2, and SO2 molecules.

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.

First-principles study of nitrogen and carbon monoxide adsorptions on silicene

2016 ◽  
Vol 30 (25) ◽  
pp. 1650176 ◽  
Author(s):  
Shuying Zhong ◽  
Fanghua Ning ◽  
Fengya Rao ◽  
Xueling Lei ◽  
Musheng Wu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Carbon Monoxide ◽  
Charge Transfer ◽  
First Principles ◽  
Density Functional ◽  
Co Adsorption ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Adsorption Energies ◽  
Charge Calculations

Atomic adsorptions of N, C and O on silicene and molecular adsorptions of N2 and CO on silicene have been investigated using the density functional theory (DFT) calculations. For the atomic adsorptions, we find that the N atom has the most stable adsorption with a higher adsorption energy of 8.207 eV. For the molecular adsorptions, we find that the N2 molecule undergoes physisorption while the CO molecule undergoes chemisorption, the corresponding adsorption energies for N2 and CO are 0.085 and 0.255 eV, respectively. Therefore, silicene exhibits more reactivity towards the CO adsorption than the N2 adsorption. The differences of charge density and the integrated charge calculations suggest that the charge transfer for CO adsorption ([Formula: see text]0.015[Formula: see text]) is larger than that for N2 adsorption ([Formula: see text]0.005[Formula: see text]). This again supports that CO molecule is more active than N2 molecule when they are adsorbed onto silicene.

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.

First Principles Calculation on Adsorption of S on Fe(100) with Different Pressure

2012 ◽  
Vol 217-219 ◽  
pp. 1811-1814
Author(s):  
Xue Tao Hu ◽  
Qiang Luo ◽  
Zeng Ling Ran
Keyword(s):  
Hydrostatic Pressure ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculation ◽  
Hollow Site ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Adsorption Energies

Using periodic density functional theory within the generalized-gradient approximation to electron exchange and correlation, we have studied S adsorption four-fold hollow site on Fe(100) in different hydrostatic pressure. We find that the adsorption height decreases with hydrostatic pressure increasing is non-monotonic. The adsorption energy decreases with an increase with pressure is monotonic and we have obtained density of states is almost unchanged, the adsorption energy change is mainly caused by lattice deformation in the hydrostatic pressure, and the adsorption energies increase linearly with pressure.

First-principles study of Li decorated coronene graphene

2017 ◽  
Vol 31 (29) ◽  
pp. 1750216
Author(s):  
Yafei zhang ◽  
Xinlu Cheng
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Storage ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Department Of Energy ◽  
First Principles Calculation ◽  
Hydrogen Storage Materials ◽  
Functional Theory ◽  
The Us

We use the first-principles calculation based on density functional theory (DFT) to investigate the hydrogen storage of Li decorated coronene graphene. Our result indicates that single Li atom can adsorb three H2 molecules and the adsorption energy per H2 is −0.224 eV. When four Li atoms doped, the largest hydrogen gravimetric density is 6.82 wt.% and this is higher than the 2017 target by the US department of energy (DOE). Meanwhile, the adsorption energy per H2 is −0.220 eV, which is suitable for H2 molecules to store. Therefore, Li decorated coronene graphene will be a candidate for hydrogen storage materials in the future.

Hydrogen Atom Adsorption on α-Al2O3(0001) Surface from First Principles

2011 ◽  
Vol 399-401 ◽  
pp. 2261-2265 ◽  
Author(s):  
Jian Gong Hu ◽  
Yi Sheng Zhang ◽  
Li Chao Jia ◽  
Bin Zhu ◽  
Hong Guang Yang ◽  
...  
Keyword(s):  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculation ◽  
Large Decrease ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
The Density Functional Theory ◽  
Low Coverage

First-principles calculation based on the density functional theory in the generalized gradient approximation was adopted to systematically investigate the α-Al2O3(0001) surface structure and the adsorption of H atom on the α-Al2O3(0001) surface. The calculations show that the O atop site is the energetically most favorable adsorption site at low coverage: at the H coverage of 1/6 ML (monolayer), the adsorption energy reaches up to7.61eV; in the regime of higher H coverages, the H atoms prefer to form atom cluster on the α-Al2O3(0001) surface, and the adsorption energy on the α-Al2O3(0001) with a pre-adsorbed H atom gets smaller, which illustrates that α-Al2O3that can prevent the penetration of hydrogen. With the increase of H coverage, the dipole moment reduces, which leads to a large decrease in the work function.

scholarly journals Theoretical Study of CO Adsorption and Activation on Orthorhombic Fe7C3(001) Surfaces for Fischer–Tropsch Synthesis Using Density Functional Theory Calculations

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 563
Author(s):  
Hee-Joon Chun ◽  
Yong Tae Kim
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Co Adsorption ◽  
Density Functional Theory Calculations ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Functional Theory ◽  
Fischer Tropsch Synthesis ◽  
Co Dissociation ◽  
Co Activation

Fischer–Tropsch synthesis (FTS), which converts CO and H2 into useful hydrocarbon products, has attracted considerable attention as an efficient method to replace crude oil resources. Fe-based catalysts are mainly used in industrial FTS, and Fe7C3 is a common carbide phase in the FTS reaction. However, the intrinsic catalytic properties of Fe7C3 are theoretically unknown. Therefore, as a first attempt to understand the FTS reaction on Fe7C3, direct CO* dissociation on orthorhombic Fe7C3(001) (o-Fe7C3(001)) surfaces was studied using density functional theory (DFT) calculations. The surface energies of 14 terminations of o-Fe7C3(001) were first compared, and the results showed that (001)0.20 was the most thermodynamically stable termination. Furthermore, to understand the effect of the surface C atom coverage on CO* activation, C–O bond dissociation was performed on the o-Fe7C3(001)0.85, (001)0.13, (001)0.20, (001)0.09, and (001)0.99 surfaces, where the surface C atom coverages were 0.00, 0.17, 0.33, 0.33, and 0.60, respectively. The results showed that the CO* activation linearly decreased as the surface C atom coverage increased. Therefore, it can be concluded that the thermodynamic and kinetic selectivity toward direct CO* dissociation increased when the o-Fe7C3(001) surface had more C* vacancies.

DENSITY FUNCTIONAL THEORY STUDIES ON THE ADSORPTION OF 4-METHYLBENZENETHIOL AND 4-ETHYLBENZENETHIOL MOLECULES ON Au(111) SURFACE

2014 ◽  
Vol 21 (06) ◽  
pp. 1450087 ◽  
Author(s):  
XIAOLIANG FANG ◽  
XIAOLI FAN ◽  
RUNXIN RAN ◽  
PIN XIAO
Keyword(s):  
Density Functional Theory ◽  
Tilt Angle ◽  
Adsorption Energy ◽  
First Principles ◽  
Density Functional ◽  
Energy Calculation ◽  
Functional Theory ◽  
Calculation Results ◽  
Adsorption Energies ◽  
First Principles Method

The nondissociative and dissociated adsorptions of 4-methylbenzenethiol (4-MBT) and 4-ethylbenzenethiol (4-EBT) on Au (111) surface were studied by applying the first-principles method based on density functional theory. The effects of coverage and vdW interactions on adsorptions were investigated. Adsorption energies and tilt angles of both 4-MBT and 4-EBT decrease with the increase of the coverage, and vdW interactions can affect the adsorption configuration and energy. More importantly, in the case of 4-EBT adsorption, we have studied the effects of ethyl group's orientation on the adsorption configuration and energy. Calculation results show that ethyl group's orientation has little effect on the adsorption energy, but changes the tilt angle by around 7°. Our calculations provide a deeper elucidation of the observed adsorption configuration for 4-EBT on Au (111).

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