scholarly journals A density functional theory study of arsenic immobilization by the Al(iii)-modified zeolite clinoptilolite

2016 ◽  
Vol 18 (16) ◽  
pp. 11297-11305 ◽  
Author(s):  
Joel B. Awuah ◽  
Nelson Y. Dzade ◽  
Richard Tia ◽  
Evans Adei ◽  
Bright Kwakye-Awuah ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Natural Zeolite ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Arsenic Acid ◽  
Functional Theory ◽  
Modified Zeolite

We present density functional theory calculations of the adsorption of arsenic acid (AsO(OH)3) and arsenous acid (As(OH)3) on the Al(iii)-modified natural zeolite clinoptilolite under anhydrous and hydrated conditions.

scholarly journals Study on the adsorption selection of CH$$_4$$ on CuO (110) versus (111) surfaces: a density functional theory study

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Long Lin ◽  
Linwei Yao ◽  
Shaofei Li ◽  
Zhengguang Shi ◽  
Kun Xie ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Adsorption Capacity ◽  
Active Sites ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Strong Adsorption ◽  
Selection Of

AbstractFinding the active sites of suitable metal oxides is a key prerequisite for detecting CH$$_4$$ 4 . The purpose of the paper is to investigate the adsorption of CH$$_4$$ 4 on intrinsic and oxygen-vacancies CuO (111) and (110) surfaces using density functional theory calculations. The results show that CH$$_4$$ 4 has a strong adsorption energy of −0.370 to 0.391 eV at all site on the CuO (110) surface. The adsorption capacity of CH$$_4$$ 4 on CuO (111) surface is weak, ranging from −0.156 to −0.325 eV. In the surface containing oxygen vacancies, the adsorption capacity of CuO surface to CH$$_4$$ 4 is significantly stronger than that of intrinsic CuO surface. The results indicate that CuO (110) has strong adsorption and charge transfer capacity for CH$$_4$$ 4 , which may provide experimental guidance.

scholarly journals Selective catalytic reduction of NO with NH3 over Cu-exchanged CHA, GME, and AFX zeolites: a density functional theory study

2021 ◽  
Author(s):  
Pei Zhao ◽  
Bundet Boekfa ◽  
Ken-ichi Shimizu ◽  
Masaru Ogura ◽  
Masahiro Ehara
Keyword(s):  
Density Functional Theory ◽  
Selective Catalytic Reduction ◽  
Density Functional ◽  
Catalytic Reduction ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Reduction Of No ◽  
Cage Size

Density functional theory calculations have been applied to study the selectivity caused by the cage size during the selective catalytic reduction of NO by NH3 over the Cu-exchanged zeolites with cha, gme, and aft cages.

scholarly journals The effect of helium nano-bubbles on the structures stability and electronic properties of palladium tritides: a density functional theory study

2014 ◽  
Vol 470 (2171) ◽  
pp. 20140357 ◽  
Author(s):  
N. K. Das ◽  
K. Rigby ◽  
N. H. de Leeuw
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Perfect Lattice ◽  
Helium Atoms ◽  
Helium Clusters ◽  
Octahedral Sites ◽  
Metal Atoms

Density functional theory calculations have been used to study the incorporation of helium in perfect and defect-containing palladium tritides, where we have calculated the energetics of incorporation and the migration behaviour. Helium atoms preferably occupy the octahedral interstitial and substitutional sites in the perfect and Pd vacancy-containing tritides, respectively. The energetics reveal that helium clusters can form in the lattice, which displace the Pd metal atoms. The defective lattice shows less expansion compared with the perfect lattice, which can accommodate the helium less easily. The path from octahedral–tetrahedral–octahedral sites is the lowest energy pathway for helium diffusion, and the energetics indicate that the helium generated from tritium decay can accumulate in or near the octahedral sites. Density of states analyses shows the hybridization between palladium d and tritium s orbitals and repulsion between palladium d and helium s orbitals, which can distort the lattice as a result of generating localized stress.

Oxides, Silicides, and Silicates of Zirconium and Hafnium; Density Functional Theory Study

2002 ◽  
Vol 716 ◽  
Author(s):  
Maciej Gutowski ◽  
John E. Jaffe ◽  
Chun-Li Liu ◽  
Matt Stoker ◽  
Anatoli Korkin
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Gate Dielectric ◽  
Density Functional Theory Calculations ◽  
Heat Of Formation ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Exchange Correlation ◽  
The Difference ◽  
Constituent Elements

AbstractIt is known that the chemistries of hafnium and zirconium are more nearly identical than for any other two congeneric elements. Thus, both zirconia and hafnia, with the dielectric constant K > 20, have emerged as potential replacements for silica (K = 3.9) as a gate dielectric. We report an important difference between the zirconia/Si and hafnia/Si interfaces based on density functional theory calculations with the Perdew-Wang 91 exchange-correlation functional on the oxides, silicides, and silicates of Zr and Hf. The zirconia/Si interface has been found to be unstable with respect to formation of silicides whereas the hafnia/Si interface is stable. The difference between the two interfaces results from the fact that HfO2 is more stable than ZrO2 (i.e. has a larger heat of formation from its constituent elements) by more than 53 kJ/mol. The hafnium silicides, on the other hand, are less stable than zirconium silicides by ca. 20 kJ/mol.

Energetics of Protonic Species in Yttrium-doped Barium Zirconate: A Density Functional Theory Study

2013 ◽  
Vol 1495 ◽  
Author(s):  
Massimo Malagoli ◽  
M.L. Liu ◽  
Hyeon Cheol Park ◽  
Angelo Bongiorno
Keyword(s):  
Density Functional Theory ◽  
Energy Cost ◽  
Direct Contact ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Barium Zirconate ◽  
Density Functional Theory Study ◽  
Surface Layers ◽  
Functional Theory

ABSTRACTDensity functional theory calculations are used to study the equilibrium energetics of protons on the surface and in the bulk of Y-doped BaZrO3. It is shown that protonic species in direct contact with Y dopants have energies lower than in perfect BaZrO3 by up to 0.4 eV. This energetic stabilization is achieved when the protonic species is in direct contact with two Y dopants. On the (001) surface of BaZrO3, protonic species are found to be energetically more stable than in the bulk by 1.1 eV and 1.6 eV on the BaO and ZrO2 surface terminations, respectively. At these terminations, the energy of protons recover the bulk value after penetrating three surface layers, and the energy cost associated with bulk incorporation is larger than 1 eV.

An innovative gas sensor system designed from a sensitive nanostructured ZnO for the selective detection of SOx molecules: a density functional theory study

2017 ◽  
Vol 41 (21) ◽  
pp. 12569-12580 ◽  
Author(s):  
Amirali Abbasi ◽  
Jaber Jahanbin Sardroodi
Keyword(s):  
Density Functional Theory ◽  
Gas Sensor ◽  
Zno Nanoparticles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Selective Detection ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Adsorption Behaviors ◽  
Doped Zno

The adsorption behaviors of SOx molecules on pristine and N-doped ZnO nanoparticles were investigated using density functional theory calculations (DFT).

The synergetic effect of aqua ligand and metal site on performance of single-atom catalysts in H2O2 synthesis: a Density Functional Theory Study

2022 ◽  
Author(s):  
Xin-Chen Zhu ◽  
Wei Zhang ◽  
Qian Xia ◽  
Anfu Hu ◽  
Jian Jiang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Rational Design ◽  
Synergetic Effect ◽  
Density Functional Theory Calculations ◽  
Single Atom ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Metal Site ◽  
Coordination Field

To study the effect of coordination field on catalytic property is critical for rational design of outstanding electrocatalyst for H2O2 synthesis. Herein, via density functional theory calculations, we built an...

Density functional theory study of transition metals doped B80 fullerene

2014 ◽  
Vol 13 (06) ◽  
pp. 1450050 ◽  
Author(s):  
Jianguang Wang ◽  
Li Ma ◽  
Yanhua Liang ◽  
Meiling Gao ◽  
Guanghou Wang
Keyword(s):  
Density Functional Theory ◽  
Outer Surface ◽  
Density Functional ◽  
Formation Energy ◽  
Magnetic Moments ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Energy Gaps ◽  
The Stability

Density functional theory calculations have been carried out to investigate 3d, Pd and Pt transition metal (TM) atoms exohedrally and endohedrally doped B 80 fullerene. We find that the most preferred doping site of the TM atom gradually moves from the outer surface ( TM = Sc ), to the inner surface ( TM = Ti and V ) and the center ( TM = Cr , Mn , Fe and Zn ), then to the outer surface ( TM = Co , Ni , Cu , Pd , and Pt ) again with the TM atom varying from Sc to Pt . From the formation energy calculations, we find that doping TM atom can further improve the stability of B 80 fullerene. The magnetic moments of doped V , Cr , Mn , Fe , Co and Ni atoms are reduced from their free-atom values and other TM atoms are completely quenched. Charge transfer and hybridization between 4s and 3d states of TM and 2s and 2p states of B were observed. The energy gaps of TM @ B 80 are usually smaller than that of the pure B 80. Endohedrally doped B 80 fullerene with two Mn and two Fe atoms were also considered, respectively. It is found that the antiferromagnetic (AFM) state is more energetically favorable than the ferromagnetic (FM) state for Mn 2- and Fe 2@ B 80. The Mn and Fe atoms carry the residual magnetic moments of ~ 3 μB and 2 μB in the AFM states.

Germanium Adsorption on SrTiO3 (001) 2×1 Surface: A Density Functional Theory Study

2012 ◽  
Vol 463-464 ◽  
pp. 484-488
Author(s):  
Jun Jie Wang ◽  
Isabelle Lefebvre
Keyword(s):  
Density Functional Theory ◽  
Electronic Structures ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Lattice Parameter ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Site Selectivity ◽  
Threading Defects

Integrating germanium on Si is one of the major challenges of epitaxial growth and presents important applicative interest. Recently, SrTiO3 was adopted as a buffer layer to accommodate the mismatch between Ge and Si. Germanium can take its bulk lattice parameter as soon as the growth begins without threading defects on SrTiO3 surface. However, the details of Ge adsorption on SrTiO3 surface are not clear. In present work, the electronic structures of Ge deposited on the SrTiO3 (001) 2×1 Double Layer (DL) TiO2 surfaces were investigated by means of density functional theory calculations. Several stable adsorption sites are identified. It is found that the germanium adsorption shows site selectivity and causes noticeable surface distortion. The charge transfer from germanium atom to surface contributes to the formation of strong Ge-O bondings and surface metallization.

Sign in / Sign up

Export Citation Format

Share Document