scholarly journals Adsorption Mechanism of Cu-Doped SnO2 (110) Surface toward H2 Dissolved in Power Transformer

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Feng Wang ◽  
Jingmin Fan ◽  
Qiuqin Sun ◽  
Qinji Jiang ◽  
She Chen ◽  
...  
Keyword(s):  
Density Functional ◽  
Adsorption Mechanism ◽  
Power Transformer ◽  
Population Analysis ◽  
Electrical Conductance ◽  
Partial Density ◽  
Mulliken Population ◽  
Overlap Population ◽  
Bridge Oxygen ◽  
Partial Atomic Charges

The content of hydrogen is a key quantity in condition assessment and fault diagnosis of power transformer. Based on the density functional theory (DFT), the adsorption mechanism of Cu-doped SnO2 surface toward H2 has been systematically studied in this work. Firstly, the relaxation, the bond length, and overlap population of both the pure and Cu-doped SnO2 are computed. To determine the optimal doping position, the formation energies of four potential sites (i.e., Sn5c, Sn6c, Sn5c-s, and Sn6c-s) are then compared with each other. The adsorption energy and the electronic structure of SnO2 surface are analysed and discussed in detail. Furthermore, to estimate the partial atomic charges and the electrical conductance, the Mulliken population analysis is also performed. It has been found that the bridge oxygen is the most favourable position. The partial density of states of H2 after adsorption is broadened and shifted close to the Fermi level. A large amount of charges would be transferred and then released back into its conduction band, leading to the reduction of resistance and the enhancement of sensitivity toward H2. The results of this work provide references for SnO2-based sensor design.

scholarly journals Effect of Intrinsic Point Defect on the Magnetic Properties of ZnO Nanowire

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jiangni Yun ◽  
Zhiyong Zhang ◽  
Tieen Yin
Keyword(s):  
Magnetic Properties ◽  
Point Defect ◽  
Density Functional ◽  
Population Analysis ◽  
First Principles Calculation ◽  
Spin Splitting ◽  
Partial Density ◽  
Intrinsic Point Defect ◽  
Zno Nanowire ◽  
Mulliken Population

The effect of intrinsic point defect on the magnetic properties of ZnO nanowire is investigated by the first-principles calculation based on the density functional theory (DFT). The calculated results reveal that the pure ZnO nanowire without intrinsic point defect is nonmagnetic and ZnO nanowire withVO,Zni,Oi,OZn, or ZnOpoint defect also is nonmagnetic. However, a strong spin splitting phenomenon is observed in ZnO nanowire withVZndefect sitting on the surface site. The Mulliken population analysis reveals that the oxygen atoms which are close to theVZndefect do major contribution to the magnetic moment. Partial density states calculation further suggests that the appearance of the half-metallic ferromagnetism in ZnO nanorod withVZnoriginates from the hybridization of the O2p states with Zn 3d states.

scholarly journals Novel Insights into the Hydroxylation Behaviors of α-Quartz (101) Surface and its Effects on the Adsorption of Sodium Oleate

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 450 ◽  
Author(s):  
Zhang ◽  
Xu ◽  
Hu ◽  
He ◽  
Tian ◽  
...  
Keyword(s):  
Sodium Oleate ◽  
Density Functional ◽  
Population Analysis ◽  
Water Molecules ◽  
Mulliken Population ◽  
Flotation Reagents ◽  
Functional Theory ◽  
Rigorous Study ◽  
Adsorption Energies ◽  
Hydroxylated Surface

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca2+-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules on the α-quartz (101) surface were first innovatively and systematically studied by DFT calculations. Both experimental and computational results consistently demonstrated that the adsorbed calcium species onto the hydroxylated structure can significantly enhance the adsorption of oleate ions, resulting in a higher quartz recovery. The calculated adsorption energies confirmed that the adsorbed hydrated Ca2+ in the form of Ca(H2O)3(OH)+ can greatly promote the adsorption of OL− on hydroxylated quartz (101). In addition, Mulliken population analysis together with electron density difference analysis intuitively illustrated the process of electron transfer and the Ca-bridge phenomenon between the hydroxylated surface and OL− ions. This work may offer new insights into the interaction mechanisms existing among oxidized minerals, aqueous medium, and flotation reagents.

scholarly journals Comparative DFT study on selective hydrogenation of acrolein catalyzed by pure Mo2C(001) and Pt/Mo2C(001)

2021 ◽  
Author(s):  
Jinrong Wu ◽  
Yanping Huang ◽  
Weiyan Wang ◽  
Wensong Li ◽  
Zhengke Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Allyl Alcohol ◽  
Active Sites ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Elementary Reactions ◽  
Bond Hydrogenation

Abstract In this paper, Density Functional Theory (DFT) calculations were conducted to study the adsorption and stepwise hydrogenation of acrolein (CH 2 =CHCH=O) on pure Mo 2 C(001) and Pt/Mo 2 C(001). The electronic properties were investigated by Mulliken population analysis. The results showed that Mo atoms obtained some electrons from surrounding Pt and C atoms, thereby enhancing the hydrogenation activity of Mo atoms around Pt atoms and forming local active sites dominated by Mo atoms around Pt atoms. As a result, the adsorption energy of the species on Pt/Mo 2 C(001) is generally higher than that on Mo 2 C(001), and the activation energies of the elementary reactions involved in stepwise hydrogenation of acrolein on Pt/Mo 2 C(001) are lower than those on Mo 2 C(001). Moreover, Pt/Mo 2 C(001) exhibits higher selectivity for C=O bond hydrogenation than Mo 2 C(001) and produces more allyl alcohol.

TiO2/GRAPHENE OXIDE HETEROSTRUCTURES FOR GAS-SENSING: INTERACTION OF NITROGEN DIOXIDE WITH THE PRISTINE AND NITROGEN MODIFIED NANOSTRUCTURES INVESTIGATED BY DFT

2019 ◽  
Vol 26 (04) ◽  
pp. 1850170 ◽  
Author(s):  
AMIRALI ABBASI ◽  
JABER JAHANBIN SARDROODI
Keyword(s):  
Graphene Oxide ◽  
Charge Transfer ◽  
Density Of States ◽  
Density Functional ◽  
Gas Sensing ◽  
Population Analysis ◽  
Molecular Orbitals ◽  
Molecular Orbital Calculations ◽  
Mulliken Population ◽  
A Charge

The gas response of metal oxide-based sensors depends strongly on its adsorption properties. To explore the potential sensing capability of pristine and nitrogen modified TiO2/graphene oxide (GO) heterostructures, the adsorption of NO2 molecule on the N-doped nanocomposites was investigated using density functional theory (DFT) calculations. Six possible configurations were simulated based on the estimated adsorption energies. The binding sites were located over the oxygen, doped nitrogen and five-fold coordinated titanium atoms of TiO2. The electronic properties including atomic Mulliken population, projected density of states and molecular orbitals were investigated in detail. The N–O bonds of the NO2 molecule were significantly increased after the adsorption process. The adsorption of NO2 molecule on the N-doped nanocomposite is more energetically favorable than the adsorption on the undoped one. The results suggest that NO2 chemisorbs on the considered nanocomposites. Mulliken population analysis reveals a noticeable charge transfer from the nanocomposite to the molecule, which indicate that NO2 acts as a charge acceptor. Molecular orbital calculations show that the highest occupied molecular orbitals (HOMOs) of the studied systems were mainly localized on the adsorbed NO2 molecule. The significant overlaps in the projected density of states (PDOS) spectra of the interacting atoms confirm the formation of chemical bonds between them. There is a direct relationship between the results of charge transfer and sensing responses. N-doped nanocomposites have better sensing response than the undoped ones. The results highlight the possibility to develop innovative highly efficient NO2 sensors based on novel TiO2/GO nanocomposites.

Theoretical study of the geometrical and electronic properties of Be2Mg+ n (n = 1–11) clusters

2019 ◽  
Vol 9 (7) ◽  
pp. 778-785 ◽  
Author(s):  
Ben-Chao Zhu ◽  
Zhang Yu ◽  
Wang Ping ◽  
Lu Zeng ◽  
Shuai Zhang
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Density Functional ◽  
Population Analysis ◽  
Dft Method ◽  
Mulliken Population ◽  
Functional Theory ◽  
Fragmentation Energy ◽  
Average Binding Energy ◽  
Ground State Structures

By using Density Functional Theory (DFT) method at the B3LYP/6-311G level, the structures, stabilities, and electronic properties of cationic Be2Mg+ n (n = 1–11) clusters have been systematically studied. The optimized geometry show that the ground state structures of cationic Be2Mg+ n (n = 1–11) clusters favor 3D structures except n = 1, 2. Furthermore, the average binding energy E b, the second-order energy differences Δ2E, the fragmentation energy Ef and the HOMO-LUMO energy Egap of the ground state of cationic Be2Mg– n (n = 1–11) clusters are calculated, the final results indicate that Be2Mg+6 and Be2Mg+9 clusters have a higher stability than other clusters. Additionally, the NCP, NEC and Mulliken population analysis reveal that the charges in cationic Be2Mg+ n (n = 1–11) clusters transfer from Mg atom to Be atoms, and strong sp hybridizations are presented in Be atoms of Be2Mg+ n clusters. Finally, the polarizability analysis indicates that the nuclei and electronic clouds of clusters are affected by external field with the increase of cluster size.

First Principles Study of Surface Properties for Silicon Carbide-Derived Structures

2012 ◽  
Vol 433-440 ◽  
pp. 306-312
Author(s):  
Hong Ge Liu ◽  
Rui Jun Zhang ◽  
Hong Yan Jin ◽  
Qiu Xiang Liu
Keyword(s):  
Silicon Carbide ◽  
Surface Properties ◽  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Nanoporous Surface ◽  
Pseudo Potential

Using first-principles ultra-soft pseudo-potential approach of the plane wave based on the density functional theory (DFT), we investigated the surface properties for silicon carbide-derived structure (i.e. SiCDS). The calculated results show that, movement of C and Si atoms caused by Si removal results in surface structural changing, and a nanoporous surface feature can be observed on the SiCDS surfaces when more Si atoms are removed. The mulliken population analysis indicates that the Si removal leads to the stronger chemical bonds between C–Si and the formation of new stronger chemical bands between C–C. From the density of states, as the Si removal proportion increases, C2p becomes gradually dominant in the SiCDS surface state electrons. Moreover, the Si removal leads to evidently different band gaps, indicating that the conductivity for SiCDS surface structures can be adjusted through the Si removal.

CO Adsorption on the AunS(n=1~6) Clusters: The First-Principles Study

2011 ◽  
Vol 341-342 ◽  
pp. 42-47
Author(s):  
Shui Lian Chi ◽  
Ming Chen ◽  
Song Lin Peng
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Co Adsorption ◽  
Bimetallic Clusters ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Au Clusters ◽  
Adsorption Energies

Density functional theory (DFT) calculations are performed to investigate CO bonded on the AunS (n=1~6) bimetallic clusters. It is found that the adsorption energies of CO on the AunS(n=1~6) clusters are greater than those on the pure Au clusters of corresponding sizes. This means that doped S atom can enhance CO adsorption on the Au clusters. Furthermore, through the Mulliken population analysis, we can see that charges transfer from the Au clusters to S atom, while charges donate to the Au clusters from the CO in CO/AunS sytem.

A DFT and HRTEM Study on MoS2/Co: Locating Promoters in Catalytic Nanostructures

2011 ◽  
Vol 1309 ◽  
Author(s):  
Manuel Ramos ◽  
Gilles Berhault ◽  
Jose Rurik Farias ◽  
Jose Trinidad Elizalde ◽  
Domingo Ferrer ◽  
...  
Keyword(s):  
Lower Energy ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Density Functional Theory Study ◽  
Mulliken Population ◽  
Strong Electron ◽  
Functional Theory ◽  
Electron Donation ◽  
Energy Package

ABSTRACTLocating cobalt promoters on catalytically MoS2 structures is a challenging task to achieve; this is due to the size on those MoS2 nanostructures. Previous reports in the literature indicate that specific locations for Co in MoS2 slabs are (1010)-plane creating either a sulfur-Co or Molybdenum-Co termination edge, due to lower energy required for the permutation Mo, S and Co to occur. We present results obtained from Density Functional Theory study done on the interface between MoS2 and Co9S8 crystal structures; the interface show an interesting thiocubane cluster and it is suspected to be the responsible for Mo-S-Co bonding to exist, along with HDS reaction. In order to understand electronic properties on thiocubane Density of States and Mulliken Population Analysis calculations were implemented using Cambridge Serial Total Energy Package (CASTEP). Results indicate a strong electron donation from Co to Mo through intermediate sulfur atom bonded to both metals while an enhanced metallic character is also found.

X-ray and DFT Investigation of (E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol Compound

2018 ◽  
pp. 454-461
Keyword(s):  
Density Functional ◽  
Theoretical Calculations ◽  
Population Analysis ◽  
Diffraction Method ◽  
Dft Method ◽  
Basis Set ◽  
X Ray Diffraction ◽  
Mulliken Population ◽  
Charge Delocalization ◽  
X Ray

(E)-4-bromo-5-methoxy-2-((o-tolylimino)methyl)phenol was investigated by experimental and theoretical methodologies. The solid state molecular structure was determined by X-ray diffraction method. All theoretical calculations were performed by density functional theory (DFT) method by using B3LYP/6-31G(d,p) basis set. The titled compound showed the preference of enol form, as supported by X-ray diffraction method. The geometric and molecular properties were compaired for both enol-imine and keto-amine forms for title compound. Stability of the molecule arises from hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed using natural bond orbital (NBO) analysis. Mulliken population method and natural population analysis (NPA) have been studied. Also, condensed Fukui function and relative nucleophilicity indices calculated from charges obtained with orbital charge calculation methods (NPA). Molecular electrostatic potential (MEP) and non linear optical (NLO) properties are also examined.

Sign in / Sign up

Export Citation Format

Share Document