Search for: adsorption-energies
A DFT study of carbon monoxide adsorption on a Si4 nano-cluster, Article Molecular Physics ; Volume 107, Issue 17 , 2009 , Pages 1805-1810 ; 00268976 (ISSN) ; Gobal, F ; Sharif University of Technology
Using the gradient-corrected hybrid density functional method of Predew, Burke, and Ernzerhof (PBEPBE) and the new hybrid meta-density functional method of Truhlar (MPW1B95), the geometry, adsorption energy, vibrational frequency, and charge distribution of carbon monoxide adsorption on a Si4 nano-cluster has been studied. Taking into account spin multicipility in the calculations, a new stable structure of CO absorbed on the Si4 cluster has been found, in addition to the previously reported structures. Exhaustive vibrational frequency analysis of optimized structures shows that some of the formerly reported structures have imaginary vibrational frequencies and are not proper stable...
Molecular dynamics simulation investigation of hexanoic acid adsorption onto calcite (1014)surface, Article Fluid Phase Equilibria ; Volume 387 , 2015 , Pages 24-31 ; 03783812 (ISSN) ; Koleini, M. M ; Ayatollahi, S ; Sharif University of Technology
In this paper we report the results of classical molecular dynamics (MD) simulation of hexanoic acid adsorption on calcite (101-4) surface plane using Pavese and AMBER force fields for calcite and hexanoic acid, respectively. Pair correlation function, strictly suggests a well-structured adsorption. Density profile indicates the adsorption occurs through double-bonded O atom of the acid head group by direct interaction with Ca atom at calcite surface. Adsorption orientation of H and double-bonded O atoms was found to be as lock and key with respect to calcite surface Ca and O atoms, facilitating an effective adsorption. Adsorption time evolution indicates that O atom adsorption is...
DFT study of nitrogen monoxide adsorption and dissociation on Rh[sbnd]Cu nano clusters, Article Journal of Alloys and Compounds ; Volume 695 , 2017 , Pages 1924-1929 ; 09258388 (ISSN) ; Nahali, M ; Gobal, F ; Sharif University of Technology
Adsorption and dissociation of NO on RhxCu4-x(x = 0–4) nano clusters were investigated using density functional theory. Adsorption energy, total charge on NO, NO bond length, and NO vibrational frequency for various modes of NO adsorption were analyzed. Adsorption from the nitrogen end of NO on the Rh atom(s) of the clusters are more favored and adsorption energies are in the −1.02 eV to −2.59 eV range. NO binds stronger to Rh-Cu mixed clusters compared to pure Cu4 cluster, so N[sbnd]O bond is significantly weakened upon adsorption on the former. NO binding to more atoms of the clusters results in a corresponding decrease of the N[sbnd]O vibrational frequency. Dissociation of NO was also...
Adsorption of pollutant cations from their aqueous solutions on graphitic carbon nitride explored by density functional theory, Article Journal of Molecular Liquids ; Volume 260 , 15 June , 2018 , Pages 423-435 ; 01677322 (ISSN) ; Shamkhali, A. N ; Tafazzoli, M ; Parsafar, G ; Sharif University of Technology
Elsevier B.V 2018
In this study, adsorption of important pollutant cations on the surface of graphitic carbon nitride (g-C3N4) was investigated by density functional theory. The calculations indicated that N6 cavity surrounded by triazine units is the most probable adsorption site on this surface. The structural optimizations also predicted a planar surface for Cr3+, and Ni2+/g-C3N4 systems while the structure of the surface for other systems indicated a considerable distortion with strong dependency on the cation size. Also, g-C3N4 surface exhibited the high adsorption energies for Cr3+, As3+, and Sb3+ ions in the gas phase. However, formation energies of the metal-aquo complexes of these cations indicated...
Towards developing efficient metalloporphyrin-based hybrid photocatalysts for CO2reduction; an: ab initio study, Article Physical Chemistry Chemical Physics ; Volume 22, Issue 40 , 2020 , Pages 23128-23140 ; Papior, N ; Zahedi, M ; Moshfegh, A. Z ; Sharif University of Technology
Royal Society of Chemistry 2020
A series of thiophene-based donor-acceptor-donor (D-A-D) oligomer substituted metalloporphyrins (MPors) with different 3d central metal-ions (M = Co, Ni, Cu, and Zn) were systematically investigated to screen efficient hybrid photocatalysts for CO2 reduction based on density functional theory (DFT) and time-dependent DFT simulations. Compared with base MPors, the newly designed hybrid photocatalysts have a lower bandgap energy, stronger and broader absorption spectra, and enhanced intermolecular charge transfer, exciton lifetime, and light-harvesting efficiency. Then, the introduction of D-A-D electron donor (ED) groups into the meso-positions of MPors is a promising method for the...
Spinel H4Ti5O12 nanotubes for Li recovery from aqueous solutions: Thermodynamics and kinetics study, Article Journal of Environmental Chemical Engineering ; Volume 9, Issue 1 , 2021 ; 22133437 (ISSN) ; Ghasemi, S ; Askari, M ; Khosravi, A ; Hasan Zadeh, A ; Alamolhoda, A. A ; Sharif University of Technology
Elsevier Ltd 2021
In this study, H4Ti5O12 nanotubes have been prepared as Li+ adsorbent by acid treatment of Li4Ti5O12 nanotubes. Li4Ti5O12 nanotubes were synthesized via a hydrothermal method in which TiO2(B) nanNotubes were used as a precursor. The prepared Li-ion sieve showed a significant high ion-exchange capacity (160.6 mgg−1) for lithium ions due to its large specific surface area of 115.4 m2 g-1 compared to the other related studies. The kinetics and isotherm investigation revealed that the pseudo-second-order equation well described the adsorption kinetics, and the Langmuir model well fitted the isotherm data. Furthermore, the low value of adsorption energy obtained from the Dubinin-Radushkevitch...
Multiway investigation of interaction between fluorescence labeled DNA strands and unmodified gold nanoparticles, Article Analytical Chemistry ; Volume 84, Issue 15 , July , 2012 , Pages 6603-6610 ; 00032700 (ISSN) ; Kompany Zareh, M ; Hormozi Nezhad, M. R ; Sharif University of Technology
The single stranded DNA can be adsorbed on the negatively charged surface of gold nanoparticles (AuNPs), but the rigid structure of double stranded DNA prevents it from adsorption. Signal of a tagged single stranded DNA will be quenched by the plasmon effect of the AuNP surface after its adsorption. This phenomenon has been used to study the DNA hybridization and interactions of two complementary 21mer oligonucleotides each tagged with a different fluorescent dye in the presence of 13 nm gold nanoparticles. The DNA strands used in this study belong to the genome of HIV. The obtained rank deficient three-way fluorescence data sets were resolved by both PARAFAC and restricted Tucker3 models....
Methane molecule over the defected and rippled graphene sheet, Article Solid State Communications ; Volume 152, Issue 15 , August , 2012 , Pages 1493-1496 ; 00381098 (ISSN) ; Neek Amal, M ; Sharif University of Technology
Adsorption of a methane molecule (CH 4) onto a defected and rippled graphene sheet is studied using ab initio and molecular mechanics calculations. The optimal adsorption position and orientation of this molecule on the graphene surface (motivated by the recent realization of graphene sensors to detect individual gas molecules) is determined and the adsorption energies are calculated. In light of the density of states, we used the SIESTA code. It is found that (i) classical force field yields adsorption energy comparable with experimental result and ab initio calculation; (ii) the periodic nature of the van der Waals potential energy stored between methane and perfect sheet is altered due to...
First principles study of oxygen adsorption on nickel-doped graphite, Article Molecular Physics ; Volume 110, Issue 13 , Feb , 2012 , Pages 1437-1445 ; 00268976 (ISSN) ; Gobal, F ; Sharif University of Technology
Density functional theory is used in a spin-polarized plane wave pseudopotential implementation to investigate molecular oxygen adsorption and dissociation on graphite and nickel-doped graphite surfaces. Molecular oxygen physisorbs on graphite surface retaining its magnetic property. The calculated adsorption energy is consistent with the experimental value of 0.1eV. It is found that substituting a carbon atom of the graphite surface by a single doping nickel atom (2.8% content) makes the surface active for oxygen chemisorption. It is found that the molecular oxygen never adsorbs on doping nickel atom while it adsorbs and dissociates spontaneously into atomic oxygens on the carbon atoms...
Adsorption and dissociation of hydrogen peroxide on small Pd xM3-x (M = Pt, Cu; X = 1-3) clusters: A hybrid density functional study, Article Molecular Physics ; Volume 109, Issue 14 , May , 2011 , Pages 1797-1804 ; 00268976 (ISSN) ; Gobal, F ; Arab, R ; Sharif University of Technology
The adsorption and dissociation of H2O2 on small PdxM3-x (M=Pt, Cu; x = 1-3) clusters is investigated using the B3PW91 hybrid density functional method. Natural bond orbitals are analysed to obtain partial charges on atoms, dipole moments, bond orders, and hybrid orbitals of the PdxM3-x-H2O2 systems. The calculated adsorption energies are in the range of -0.32 to -2.12 eV. Generally, H2O2 adsorbs on top positions through one of its oxygen atoms and only in a few cases reacts with the cluster through both oxygen and hydrogen sides. In the latter case the cluster sites which are negatively charged interact with the hydrogen atoms. Interestingly, on the triplet Pd2Pt cluster, H2O2 dissociates...
Theoretical study of nitrogen monoxide adsorption on small Six (x = 3-5) clusters, Article Molecular Physics ; Volume 109, Issue 2 , 2011 , Pages 229-237 ; 00268976 (ISSN) ; Gobal, F ; Sharif University of Technology
Theoretical study of nitrogen monoxide adsorption on small Six (x = 3-5) clusters has been carried out using the advanced hybrid meta-density functional method of Truhlar (MPW1B95). MG3 semi-diffuse basis sets were employed to improve the results. The geometry, adsorption energy, natural bond orbital charge, natural population analysis (NPA)-derived spin density and vibrational frequency of NO adsorption on all optimized nanoclusters were investigated. Also using the NPA, we have investigated the change of bond orders through adsorption. It has been found that NO is capable of making n-centre bonds (n = 1-4) from the nitrogen side but bonds to one site from the oxygen end. In the later case...
Theoretical study of CO adsorption on the illuminated TiO2 (0 0 1) surface, Article Applied Surface Science ; Volume 256, Issue 12 , 2010 , Pages 3795-3798 ; 01694332 (ISSN) ; Sadighi Bonabi, R ; Sharif University of Technology
A quantum modeling of the CO adsorption on illuminated anatase TiO2 (0 0 1) is presented. The calculated adsorption energy and geometries of illuminated case are compared with the ground state case. The calculations were achieved by using DFT formalism and the BH and HLYP. Upon photoexcitation, an electron-hole pair is generated. Comparing of natural population in the ground state and the exited state, shows that an electron is trapped in a Ti4+ ion and a hole is localized in an oxygen ion. The photoelectron helps generation of a CO2 molecule on the TiO2 surface. As shown by optimization of these systems, the CO molecule adsorbed vertically on the TiO2 (0 0 1) surface in the ground state...
First-principles study of molecule adsorption on Ni-decorated monolayer MoS2, Article Journal of Computational Electronics ; Volume 18, Issue 3 , 2019 , Pages 826-835 ; 15698025 (ISSN) ; Berahman, M ; Asgari, R ; Sharif University of Technology
Springer New York LLC 2019
The interactions between four different gas molecules (methanol, o-xylene, p-xylene and m-xylene) and Ni-decorated monolayer MoS2 were investigated by means of density functional computations to exploit its potential application as a gas sensor. The electronic properties of the Ni-decorated monolayer MoS2 and gas molecule (adsorbent–adsorbate properties) strongly depend on the Ni-decorated monolayer MoS2 structure and the molecular configuration of the adsorbate. The adsorption properties of volatile organic compound (VOC) molecules on Ni-decorated MoS2 has been studied taking into account the parameters such as adsorption energy, energy bandgap, density of states, and Mulliken charge...
Spinel H4Ti5O12 nanotubes for Li recovery from aqueous solutions: Thermodynamics and kinetics study, Article Journal of Environmental Chemical Engineering ; 2020 ; Shahnaz, G ; Askari, M ; Khosravi, A ; Hasan Zadeh, A ; Alamolhoda, A. A ; Sharif University of Technology
Elsevier Ltd 2020
In this study, H4Ti5O12 nanotubes have been prepared as Li+ adsorbent by acid treatment of Li4Ti5O12 nanotubes. Li4Ti5O12 nanotubes were synthesized via a hydrothermal method in which TiO2(B) nanNotubes were used as a precursor. The prepared Li-ion sieve showed a significant high ion-exchange capacity (160.6 mgg-1) for lithium ions due to its large specific surface area of 115.4 m2 g-1 compared to the other related studies. The kinetics and isotherm investigation revealed that the pseudo-second-order equation well described the adsorption kinetics, and the Langmuir model well fitted the isotherm data. Furthermore, the low value of adsorption energy obtained from the Dubinin-Radushkevitch...
Adsorption of carbon monoxide on SixGe4-x(x = 0-4) nano-clusters: A hybrid meta density functional study, Article Molecular Physics ; Volume 108, Issue 10 , 2010 , Pages 1317-1327 ; 00268976 (ISSN) ; Gobal, F ; Sharif University of Technology
Theoretical study of carbon monoxide adsorption on SixGe4 - x(x = 0-4) nano-clusters has been carried out using advanced hybrid meta density functional method of Truhlar (MPW1B95). MG3 semi-diffuse (MG3S) and correlation consistent valence basis sets with relativistic core potential were employed to improve the results. The agreement of the calculated ionization and dissociation energies with experimental values validates the reported structures of nano-clusters and justifies the use of hybrid meta density functional method. The geometry, adsorption energy, charge distribution, and vibrational frequency of CO adsorption on all possible structures were investigated. The maximum vibrational...