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Öğe A Density Functional Theory Study on Rechargeable Mg-ion Batteries: C20 Fullerene as a Promising Anode Material(Wiley, 2022) Köse, Ahmet; Yüksel, Numan; Fellah, Mehmet FerdiIn this study, the applicability of C-20 fullerene as anode material in Mg-ion batteries was investigated by Density Functional Theory (DFT). The interaction energy of the Mg2+ ion on C-20 structure was found as -147.3 kcal/mol. The HOMO-LUMO gap value decreased during Mg interaction on C-20 structure while it increased during Mg2+ interaction. The charge distributions obtained after the interactions of Mg atoms on C-20 show that charge transfer has taken place. The storage capacity value of C-20 structure was calculated to be 893 mAhg(-1). The diffusion barrier was calculated as 1.9 kcal/mol. In addition, the diffusion coefficient for Mg and Mg2+ on C-20 structure were computed as 1.5x10(-25) and 4.61x10(-4), respectively. Consequently, the high storage capacity, high conductivity and low diffusion barrier for discharge/charge process and the suitability of the diffusion coefficient suggest that C-20 fullerene structure can be used as a potential anode material in rechargeable Mg-ion batteries.Öğe Acetaldehyde adsorption and detection: A density functional theory study on Al-doped graphene(Pergamon-Elsevier Science Ltd, 2020) Serinçay, Nazmiye; Fellah, Mehmet FerdiIn this study, the Al-doped graphene structure was investigated as a sensor for the detection of acetaldehyde molecules at room temperature using density functional theory (DFT). The hybrid B3LYP method with 6-31G (d, p) basis set was used for all structural elements in the calculations. All structural and electronic properties were investigated. Among the properties studied, the charge distribution after adsorption has been determined to be the charge transfer from the acetaldehyde molecule to the cluster, and the electron acceptor in the system is an Al-doped graphene structure. However, it was found that the HOMO-LUMO gap decreased significantly after acetaldehyde molecule adsorption to the cluster. The results show that the acetaldehyde molecule with significant charge transfer and high adsorption energy can be adsorbed on the Al-doped graphene structure. As a conclusion, the electrical conductivity of Al-doped graphene structure increased with acetaldehyde adsorption. All these results show that the Al-doped graphene structure has the potential to be a sensor for the determination of acetaldehyde molecule at room temperature.Öğe Adsorption of hydrogen sulfide as initial step of H2S removal: A DFT study on metal exchanged ZSM-12 clusters(Elsevier, 2016) Fellah, Mehmet FerdiThe molecular adsorption of hydrogen sulfide has been theoretically studied via DFT on additional framework with cations of metals (Fe, Co, Ni, Cu and Zn) in 14T-channel ZSM-12 zeolite cluster model. The method employed in this study is B3LYP functional with LanL2DZ and 6-31 G(d,p) basis sets. Cu-ZSM-12 cluster has the lowest chemical potential with minimum adsorption energy value with negative Delta G, highest electronegativity and lowest energy gap between HOMO and LUMO with respect to other clusters. It is softer than other clusters because of its lower chemical hardness value. Accordingly, based on these data it can be mentioned that Cu-ZSM-12 is a promising candidate catalyst as for removal of hydrogen sulfide via activation of S-H bond than other metal ZSM-12 zeolites. (C) 2016 Elsevier B.V. All rights reserved.Öğe Adsorption of SO2 on Wool Fiber: An Experimental and DFT Study(Taylor & Francis Inc, 2022) Gazioğlu Rüzgar, Duygu; Altun Kurtoglu, Sule; Fellah, Mehmet FerdiIn this study, the washed-combed wool fiber and the washed-combed-dyed wool fiber were used to investigate pollutant gas sorption capacity of wool fibers. Sulfur dioxide (SO2) was selected as the pollutant gas since it is one of the mostly found pollutants in air content. The wool fiber samples were tested with gaseous pollutant for different time periods and gas adsorption values were measured. Furthermore, SO2 adsorption was studied theoretically by density functional theory (DFT) calculations with B3LYP 6-31 G (d,p)/method on amino acids were found to be in good agreement with experimental data.Öğe Bimetallic platinum-rhodium nanocomposites for dimethylamine borane dehydrogenation: an experimental and density functional theory study(Royal Soc Chemistry, 2020) Alptekin, Oznur; Sen, Betul; Acidereli, Hilal; Ercetin, Umran; Fellah, Mehmet Ferdi; Sen, FatihIn this study, bimetallic platinum-rhodium nanocomposites supported on graphene oxide (PtRh@GO) were synthesized and used as a catalyst in the dimethylamine borane (DMAB) dehydrogenation. The synthesized PtRh@GO catalyst was characterized using spectral and microscopic methods. The characterization studies revealed that the obtained PtRh@GO nanomaterials were nano-sized and exhibited a monodisperse distribution on GO. As a result of the catalytic studies, it was determined that the dehydrogenation reaction of dimethylamine borane depends on the temperature, amount of catalyst, and substrate. Additionally, some kinetic data and activation parameters were investigated for the dimethylamine dehydrogenation of DMAB with the help of PtRh@GO. The kinetic and activation parameters showed that the PtRh@GO catalyst could be used effectively. The activation energy (E-a) was found to be 17 +/- 2 kJ mol(-1)for the dimethylamine borane dehydrogenation. Using previously performed studies, comparison studies for the turnover frequency (TOF) value of the PtRh@GO catalyst in the dimethylamine borane reaction showed that the obtained PtRh@GO catalyst could be used effectively with a higher TOF (274.6 h(-1)) value. In addition, DFT computations were utilized on the structure of PtRh@GO in order to investigate the activity of the catalyst. The experimental data have been supported by the theoretical results based on DFT.Öğe Boron and nitrogen doping in graphene: an experimental and density functional theory (DFT) study(IOP Publishing, 2020) Kaykılarlı, Cantekin; Uzunsoy, Deniz; Şam Parmak, Ebru Devrim; Fellah, Mehmet Ferdi; Çakır, Özgen ÇolakBoron (B) and Nitrogen (N) doped few layer graphene (BNG) is directly synthesized via electric arc discharge (EAD) method. NH3 and BCl3 gas mixtures are used in the synthesis atmosphere. Raman spectroscopy is used to determine graphene's purity and number of layers. The investigation of structure and morphology of pristine graphene and BNG are carried out via Transmission Electron Microscopy (TEM). The presence of B and N in the structure of graphene is detected by Energy Dispersive X-ray Spectroscopy (EDS) analysis. Elemental mapping show that N and B are distributed homogeneously in the graphene structure. It is observed that doping process did not affect the positions of the D, G and 2D bands in the Raman spectroscopy. The effect of doping on the number of layers of graphene is found negligible. TEM results exhibit that pristine graphene and BNG have 5 to 6 layers. Besides, the theoretical calculations based on Density Functional Theory (DFT) are employed to support experimental studies. Theoretical results based on DFT showed that bonding of B and N is favorable.Öğe Carbon nanotubes doped with Ni, Pd and Pt: A density functional theory study of adsorption and sensing NO(Elsevier, 2020) Demir, Selin; Fellah, Mehmet FerdiIn present work, the Density-Functional-Theory computations were applied for the platinum, nickel and palladium doped (6,0) single-walled carbon nanotubes (SWCNTs) to investigate the utility for NO gas sensing at the temperature of 25 degrees C. The method of WB97XD was used with the basis sets of 6-31 G (d,p) and LanL2DZ. The geometrical properties and electronic parameters were found for all structures. The charge distributions mentioned that the charge transfer has been occurred from the Ni, Pd and Pt doped SWCNTs as an electron donor to the adsorbed NO molecule. The HOMO-LUMO energy gap, which provides important knowledge about chemical stability, only decreased after the adsorption of NO molecule on the Pt-SWCNT cluster. Consequently, consistent with these results Pt-doped (6,0) SWCNT could provide useful benefits for the design and manufacture of NO sensor at room temperature.Öğe Composites of Platinum-Iridium Alloy Nanoparticles and Graphene Oxide for the Dimethyl Amine Borane (DMAB) dehydrogenation at ambient conditions: An Experimental and Density Functional Theory Study(Nature Publishing Group, 2019) Sen, Betul; Aygun, Aysenur; Savk, Aysun; Calimli, Mehmet Harbi; Fellah, Mehmet Ferdi; Sen, FatihIn this paper, we present the synthesis, characterization, catalytic and computational studies of Composites of Platinum-Iridium Alloy Nanoparticles and Graphene Oxide (PtIr@GO) for dimethylamine borane (DMAB) dehydrogenation. The prepared PtIr@GO nanocatalysts were synthesized using an ethanol super-hydride method, and the characterization procedures for PtIr@GO alloy nanoparticles were carried out by various advanced spectroscopic methods like X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscopy(TEM) and high-resolution transmission electron microscopy (HRTEM). Additionally, catalytic activity, reusability, substrate concentration, and catalyst concentration experiments were performed for DMAB dehydrogenation catalyzed by PtIr@GO alloy nanomaterials. According to the results obtained in this study, PtIr@GO NPs catalyst was found to be active and reusable for the DMAB even at ambient conditions. Besides, DFT-B3LYP calculations have been utilized on PtIr@GO cluster to reveal the prepared catalyst activity. The calculated findings based on DFT was found to be a good agreement with experimental results.Öğe Density functional theory investigation of acetylene dehydrogenation on metal exchanged ZSM-5 clusters for initial step of carbon nanotube production(Elsevier Science Bv, 2013) Tezsevin, Ilker; Fellah, Mehmet Ferdi; Onal, IsikAdsorption and dehydrogenation of acetylene have been theoretically studied on [M(SiH3)(4)AlO4] and [(M-(mu-O)-M)Si6Al2O9H14] (where M = Co, Fe, Ni, and V) clusters representing ZSM-5 zeolite. Adsorption and dehydrogenation of acetylene were performed as an initial step of carbon nanotube synthesis by using Density Functional Theory calculations with utilization of B3LYP formalism. If activities of different clusters are compared, M-(mu-O)-M-ZSM5 clusters show better performance than the M-ZSM5 clusters for acetylene activation. Activation barriers of Ni-(mu-O)-Ni-ZSM5 and Co-(mu-O)-Co-ZSM5 clusters are lower than those of other ZSM-5 clusters. It can be therefore concluded that Ni-(mu-O)-Ni-ZSM5 and Co-(mu-O)-Co-ZSM5 catalysts can be used for H removal from acetylene as an initial step for carbon nanotube production. (C) 2013 Elsevier Inc. All rights reserved.Öğe A Density Functional Theory study for adsorption and sensing of 5-Fluo-rouracil on Ni-doped boron nitride nanotube(Elsevier, 2021) Yüksel, Numan; Köse, Ahmet; Fellah, Mehmet FerdiIn this research, the use of Ni-doped (8,0) boron nitride nanotube (Ni-BNNT) as both a sensor and an adsorbent for 5-Fluorouracil (5-FU) molecule was investigated by Density Functional Theory (DFT) method. The B3LYP method with 6-31G(d,p) basis set have been utilized. Six different adsorption configurations have been studied theoretically. After 5-FU adsorption on Ni-BNNT, the adsorption energy values were calculated as negative values in all configurations. Adsorption energy (Delta E) value and adsorption enthalpy (Delta H) value reached 0.75 eV and -0.78 eV values, respectively. Moreover, Gibbs free energy changes were computed to be negative values in all configurations and thus it was determined that the process could occur spontaneously. Charge transfer occurred between all configurations of Ni-BNNT and the 5-FU molecule. The HOMO-LUMO gap decreased in the NiN-BNNT (Ni-doped instead of N) structure, while it increased in the Ni-B-BNNT (Ni-doped instead of B) structure. The Ni-BNNT structure assistances from a recovery time as a sensor for 5-FU drug molecule. Moreover, the workfunction change occurred somewhat in all configurations, but it was calculated that there was more change (16.22%) in the NiN-O1-BNNT configuration. In addition, solvent (water) effect was also examined. Consequently, Ni-doped (8,0) BNNT structure can be used as both a sensor and an adsorbent for 5-FU molecule at room temperature.Öğe A density functional theory study of [(4-aminophenyl)imino]methyl-6-methoxy 4-nitrophenol complexes with Co,Ni,Cu and Zn metals(Scientific Publishers, 2014) Fellah, Mehmet Ferdi; Bakirdere, E.G.; Canpolat, E.; Kaya, M.The optimization and IR spectra of the [(4-aminophenyl)imino]methyl-6~methoxy-4-nitrophenol and its complexes with Co, NI, Cu and Zn metals were determined by means of density functional theory (DFT) calculations using B3LYP formalism. The optimized geometries of complexes have tetrahedral structures. The C=N, C-O and N-H stretching frequency values were calculated to be in good agreement with experimental frequency data for ligand and its complexes with metals. Ail calculated frequencies are within 1.1% of the regions of experimental frequencies. © 2014 Scientific Publishers. All Rights Reserved.Öğe A density functional theory study of [(4-aminophenyl)imino]methyl-6-methoxy-4-nitrophenol complexes with Co, Ni, Cu and Zn metals(Scientific Publ-India, 2014) Fellah, Mehmet Ferdi; Bakirdere, Emine Gulhan; Canpolat, Erdal; Kaya, MehmetThe optimization and IR spectra of the [(4-aminophenyl)imino]methyl-6-methoxy-4-nitrophenol and its complexes with Co, Ni, Cu and Zn metals were determined by means of density functional theory (DFT) calculations using B3LYP formalism. The optimized geometries of complexes have tetrahedral structures. The C=N, C-O and N-H stretching frequency values were calculated to be in good agreement with experimental frequency data for ligand and its complexes with metals. All calculated frequencies are within 1.1% of the regions of experimental frequencies.Öğe A density functional theory study of hydrogen adsorption on Be-, Mg-, and Ca-exchanged LTL zeolite clusters(Springer, 2017) Fellah, Mehmet FerdiHydrogen molecule adsorption on frameworks consisting of alkaline earth metal atoms (Be, Mg, or Ca) in LTL zeolite was investigated via density functional theory. A 24T zeolite cluster model was used in this study. HOMO and LUMO energy, chemical potential, chemical hardness, electro-negativity, adsorption energy, and adsorption enthalpy values were calculated. The Mg-LTL and Ca-LTL clusters were found to have much lower chemical potentials and adsorption energies than those of the Be-LTL cluster. Additionally, the calculations indicated that the Mg-LTL and Ca-LTL clusters are softer (considering their lower chemical hardness values) and more chemically reactive than the Be-LTL cluster. The calculated hydrogen adsorption enthalpies were -14.7 and -9.4 kJ/mol for the Mg-LTL and Ca-LTL clusters, respectively, which are significantly larger than the enthalpy of liquefaction for the hydrogen molecule. These results imply that the Mg-LTL and Ca-LTL zeolite structures are promising cryoadsorbents for hydrogen storage.Öğe A Density Functional Theory study of molecular hydrogen adsorption on Mg site in OFF type zeolite cluster(Pergamon-Elsevier Science Ltd, 2020) Yüksel, Numan; Köse, Ahmet; Fellah, Mehmet FerdiIn this study, hydrogen molecule adsorption was investigated on additional framework of Mg atom in OFF type zeolite by way of DFT (Density Functional Theory). The adsorption enthalpy and adsorption energy, chemical potential, HOMO energy, electronegativity, LUMO energy, chemical hardness values have been computed on a 8T zeolite cluster model and compared with those of Mg exchanged ERI, LTL and DFT zeolite structures previously reported in literature. Hydrogen adsorption enthalpy value was computed as -17 kJ/mol. This value is meaningfully larger than the hydrogen molecule's liquefaction enthalpy value. This accordingly specifies that Mg-OFF zeolite structure appears to be an encouraging candidate cryoadsorbent for hydrogen storing. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe A Density Functional Theory Study of NO Reduction by C3H8 Aided Selective Catalytic Reduction Method(Springer, 2015) Tezsevin, Ilker; Onay, Deniz; Fellah, Mehmet Ferdi; Onal, IsikIn this theoretical work sequential adsorption of H-2 and O-2 on a Ag (7) (+) cluster surface is first studied and Ag (7) (+) H2O2 cluster co-complex thereby obtained is used for the NO reduction process. This cationic charged silver nano cluster simulates small Ag crystals experimentally detected on gamma-Al2O3 support. For NO reduction, three different mechanisms and intermediate steps of these mechanisms reported in experimental literature are examined. Energy profiles, activation barriers and transition states of the reaction steps involved are studied. Some intermediate steps turned out to have high activation barriers. Hence a combined mechanism selected from the favorable steps found in these three mechanisms is proposed. By using this combined mechanism, reduction of NO to N-2 is achieved.Öğe A Density Functional Theory Study on Graphene Triple Doped with Ga, Ge, P, Si, and Al(MAIK NAUKA, 2022) Serinçay, Nazmiye; Fellah, Mehmet FerdiThe basic properties of graphene surfaces doped with Ga, Ge, P, Si, and Al were investigated using DFT (density functional theory). The structural, electrical, chemical and optical properties obtained by doping three elements onto the graphene structures modeled as a single layer were obtained in quantum chemical calculations with the WB97XD/6-31G(d,p) method. The HOMO-LUMO gap value, which expresses its chemical hardness, has decreased in the graphene structures doped with Ga-Ga-Ga, Ge-Ge-Ge, P-P-P, Si-Si-Si, and Al-Al-Al. Increased rigidity in doped graphene structures, increased movement of the system towards a more stable configuration, higher stability of the electronic structure, high chemical reactivity, high chemical potential, low electronegativity value, and high electrical conductivity. Increasing properties of element-doped graphene structures have predicted the structure's use in electronic devices such as transistors, energy storage devices, conductors, and sensors.Öğe Design, synthesis, characterization, and antimicrobial activity of the new 2-{(E)-[(4-aminophenyl)imino]methyl}-4,6-dichlorophenol and its complexes with Co(II), Ni(II), Cu(II) and Zn(II): An experimental and DFT study(Serbian Chemical Soc, 2016) Bakirdere, Emine Gulhan; Fellah, Mehmet Ferdi; Canpolat, Erdal; Kaya, Mehmet; Gur, SeherIn this study, the complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 2-{(E)-[(4-aminophenyl)imino]methyl}-4,6-dichlorophenol were prepared and characterized by physical, spectral and analytical data. The metal:ligand stoichiometric ratio was 1:2 in all the complexes. The results suggested that the Schiff bases were coordinated to the metal ions through the phenolic oxygens and the azomethine nitrogen to give mononuclear complexes. Their structures were elucidated based on elemental analysis, IR, H-1- and C-13-NMR, UV-Vis, and magnetic susceptibility measurements and thermogravimetric analyses. Both the antibacterial and antifungal activities and the minimum inhibitory concentration (MIC) values of compounds are reported. Among the tested compounds, the most effective compound providing an MIC value of 64 mu g mL(-1) was Zn(L)(2) against Candida tropicalis and Bacillus subtilis. The theoretically optimized geometries of the complexes were tetrahedral structures. The computed stretching frequencies of the C=N, C-O and N-H bonds were in good agreement with the experimental data. All the calculated frequencies fell within about 5 % of the experimental frequency regions.Öğe A DFT investigation of hydrogen adsorption and storage properties of Mg decorated IRMOF-16 structure(ELSEVIER, 2022) Yüksel, Numan; Köse, Ahmet; Fellah, Mehmet FerdiHerein, the hydrogen storage property of the Mg decorated isoreticular metal organic framework-16 (IRMOF-16) is investigated by Density Functional Theory (DFT) method. The WB97XD hybrid method (including dispersion) was used for hydrogen adsorption on Mg decorated IRMOF-16 structure. It was determined that the adsorption enthalpy for the structure was negative (-4.2 kJ/mol) at room temperature and thus it could be a potential adsorbent material for the hydrogen. The gravimetric hydrogen storage capacity of the IRMOF-16 structure decorated with four Mg atoms was determined as ~5.8 wt%. According to the electronic properties, it was revealed that the Mg-IRMOF-16 structure could not be used as an electronic sensor against the hydrogen molecule.Öğe DFT Study of Direct Methanol Oxidation to Formaldehyde by N2O on the [Fe](2+)-ZSM-5 Zeolite Cluster(Amer Chemical Soc, 2012) Fellah, Mehmet Ferdi; Onal, IsikThe mechanistic pathways of direct oxidation of methanol to formaldehyde by N2O were theoretically investigated by means of density functional theory (DFT) over an extra framework species in ZSM-5 zeolite represented by a [Si6Al2O9H14](2-)[Fe](2+) cluster model. The catalytic reactivity of these species is compared with that of mononuclear Fe1+ and (FeO)(1+) sites in ZSM-5 investigated in our earlier work at the same level of theory (J. Catal. 2011, 282, 191). The formation of the grafted species including methoxy on the [Fe](2+) site was calculated to be thermodynamically more stable than on the [FeO](1+) site and less stable than on the [Fe](1+) site. The order of activation barrier values of a critical step, proton transfer from grafted methoxy to form formaldehyde and water, on these sites is as follows: [Fe](1+) > [Fe](2+) >> [FeO](1+). The calculated vibrational frequencies for grafted species on the iron site on the surface are in good agreement with the experimental values.Öğe A DFT Study of Ethylene Hydrogenation Reaction Mechanisms on Ni-13 Nanocluster(Springer/Plenum Publishers, 2013) Fellah, Mehmet Ferdi; Onal, I.Metal nanoclusters can potentially exhibit high catalytic activity and selectivity due to not only a high number of exposed surface atoms but also active sites with different coordination numbers as compared to bulk catalyst surface. In this study ethylene hydrogenation was used as a model reaction in an effort to elaborate reactivity of small Ni nanoclusters and the ethylene hydrogenation reaction mechanism. Two mechanistic pathways; representing Eley-Rideal and Horiuti-Polanyi type of mechanism for ethylene hydrogenation reaction are studied. It has been concluded that Horiuti-Polanyi type is more favorable when compared to Eley-Rideal type.
