Publications Internationales
Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/13
Browse
9 results
Search Results
Item Theoretical Study of Copper Squarate as a Promising Adsorbent for Small Gases Pollutants(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Adjal, Celia; Guechtouli, Nabila; Timón, Vicente; Colmenero, Francisco; Hammoutène, DalilaCopper squarate is a metal–organic framework with an oxo-carbonic anion organic linker and a doubly charged metal mode. Its structure features large channels that facilitate the adsorption of relatively small molecules. This study focuses on exploring the potential of adsorbing small pollutants, primarily greenhouse gases, with additional investigations conducted on larger pollutants. The objective is to comprehend the efficacy of this new material in single and multiple molecular adsorption processes using theoretical methods based on density functional theory. Furthermore, we find that the molecular adsorption energies range from 3.4 KJ∙mol−1 to 63.32 KJ∙mol−1 depending on the size and number of adsorbed molecules. An exception is noted with an unfavorable adsorption energy value of 47.94 KJ∙mol−1 for 4-nitrophenol. More importantly, we demonstrate that water exerts an inhibitory effect on the adsorption of these pollutants, distinguishing copper squarate as a rare MOF with hydrophilic properties. The Connolly surface was estimated to give a more accurate idea of the volume and surface accessibility of copper squarate. Finally, using Monte Carlo simulations, we present a study of adsorption isotherms for individual molecules and molecules mixed with water. Our results point out that copper squarate is an efficient adsorbent for small molecular pollutants and greenhouse gases.Item Study of Structural, Elastic, Thermal and Transport Properties of Ternary X(X=Co, Rh and Ir)MnAs Obtained by DFT(V N Karazin Kharkiv National University, 2022) Kadri, Salim; Tourab, Mohamed; Berkani, Mahièddine; Amraoui, Rabie; Bordjiba, ZeynebThe Density Functional Theory (DFT) with an approximation of generalised gradient is used for the study of elastic, thermodynamic and transport properties and for that of structural stability of ternary Half-Heuslers compounds X(X=Co, Rh and Ir)MnAs. This first predictive study of this compounds determines the mechanical properties such that the compression, shearing, Young modulla and Poisson coefficient without omitting the checking parameters of the nature of these compounds such that hardness, Zener anisotropic facto rand Cauchy pressure. The Pugh ratio and Poisson coefficient have allowed the identification of ductile nature of these compounds. The speed of sound and Debye temperature of these compounds has also been estimated from the elastic constants. The thermodynamic properties have been calculated as well for a pressure interval from zero to 25 GPa. The effect of chemical potential variation on Seebeck coefficient, electric, thermal and electronic conductivities, the power and merit factors have also been studied for different temperatures (300, 600, 900°K), so that these alloys can be better potential candidates for thermoelectric applicationsItem Out-of-plane ionicity versus in-plane covalency interplay and electron–phonon coupling in MgB 2 superconductor(Elsevier, 2020) Guerfi, T.Using the Density Functional Theory (DFT) within the Generalized Gradient Approximation (GGA) pseudopotential and plane wave basis method along with the frozen-phonon approach that starts from the ab initio evaluation of the total energy Etot of the solid with frozen-in atomic displacements, it is found that a superposition of A2u and the E2gvibrations modes is the key factor in the superconducting mechanism in MgB2 compound. Electron–Phonon coupling to these A2u and E2g phonon modes especially at the zone-boundary A point of the hexagonal Brilliouin zone leads to an interband hole charge transfer (and transfer back) between in-plane σ bond to the out-of-plane π bond along with an interatomic electron charge transfer (and transfer back) between the Magnesium s-states to the Boron out-of-plane pz-state. The direction of the electronic current is opposite to that of hole current so that it reinforces the polarization associated with these currents and may generate a large dynamical charge at a given critical temperature Tc that drives the compound into the superconducting stateItem Mechanistic details of methane dry reforming on copper-nickel bimetallic surfaces(Elsevier, 2020) Boualouache, Adel; Boucenna, AliUsing spin polarized DFT, we performed mechanistic studies of methane dry reforming on Cu-Ni bimetallic surfaces. We computed the local density of states (LDOS) of intermediates/surfaces to analyse chemical bonding on different Cu-Ni alloys. Our results show that carbon resistance of low Cu amount surfaces is related to a reduced interaction of CH 1π orbital with 3d states. Likewise, the lowering of (1π, 2π* −3d) binding intensity, catalyses CO desorption rather than its retention and/or activation, enhancing CO anti-poisoning.Item Adsorption and diffusion of oxygen atom on UN2(100) surface and subsurface : a density functional theory study (DFT and DFT + U)(Springer, 2014) Zergoug, Toufik; Abaidia, Seddik-El-Hak; Nedjar, A.; Mokeddem, Mohamed YazidIn the present work, adsorption and dif fusion of oxygen (O) atom on uranium dinitride (UN2) is studied to map out the preferential UN2(100) surface site. The first principle method based on density functional theory (DFT) within the generalized gradient approximation PBE and the covariant version energy functional PBE + U correction were used. The supercell approach and a coverage dependence of the adsorption structures and energetic were studied in detail for several monolayers’ (ML) range. Potential energy surfaces (PES) corresponding to the interaction between O atom and UN2(100) on surface and subsurface for several sites and layers (Top U and Top N slabs) were calculated and favorable sites were identified with their maxima energy stable positions, which were then analyzed. For all positions, the PES show the same system behavior, when the O atom is sufficiently far from the UN2 surface, and the energy of the system tends to the sum of free UN2 slab and free oxygen atom energies. In return, when the distances decrease, strong interactions appear with presence of important potential wells. Calculation results showed that favored on-surface site for O atom adsorption were found to be near the bridge one for the UN (Top U slab) corresponding to five layers, uranium terminated and top one for (Top N slab) corresponding to six layers nitrogen terminated, the maximum system energy is situated at a position of about 1.2 and 1.5 Å from the surface for the two layers types calculations respectively. For subsurface results, only Top N presents a favorable incorporation site at the hollow position and the penetration of O atom is about −0.5 Å from the surface. DFT + U study confirms all the results obtained by DFT calculations; that is, the maxima site positions for oxygen atom and the adhesion energy values per atom are of the same order of magnitudes. The adsorption energy per oxygen atom and the mean distance from the top surface gradually decrease with the coverage of O atoms for both on-surface cases, Top U and Top N slabs, with oxygen occupying the favorable site. For the Top N slab hollow site, the incorporation of oxygen through the surface becomes effective from a coverage of 3/8 ML with an encrustation of about −0.3 ÅItem What is the real existing form of imexon? - Quantum chemical studies(Elsevier, 2010) Kheffache, Djaffar; Ouamerali, O.Item First principle study of oxygen diffusion on uranium nitride UN(001) surface with uranium or nitrogen vacancies(Bentham Science Publishers, 2015) Zergoug, Toufik; Abaidia, Seddik-El-Hak; Nedjar, A.Item Conformational and NMR analysis on cis 1,3-indanediol(Elsevier, 2011) Guemmour, Hind; Kheffache, Djaffar; Benaboura, AhmedItem Conformational analysis and intramolecular hydrogen bonding of cis-3-aminoindan-1-o l : a quantum chemical study(Springer, 2013) Kheffache, Djaffar; Guemmour, Hind; Dekhira, Azzedine; Benaboura, Ahmed; Ouamerali, Ourida