Yazar "Levent, Abdulkadir" seçeneğine göre listele

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    Enhanced electrochemical performance of ZnO@sulphur-doped carbon particles for use in supercapacitors
    (Elsevier, 2024) Levent, Abdulkadir; Saka, Cafer
    Here, the electrochemical performance of ZnO@sulphur-doped carbon particles from banana peels in three stages for use in supercapacitors was investigated. The first stage involves the production of activated carbon from banana peel by NaOH activation (BPAC). The second stage involves the production of sulphur-doped BPAC (BPAC-S) by sulphuric acid activation of the obtained BPAC sample. In the third stage, the ZnO-doped BPAC-S sample was produced by ZnO doping using hydrothermal process. The electrochemical performances of the obtained BPAC-S and ZnO-doped BPAC-S samples were investigated in supercapacitor application as an electrode material. The characterization of the obtained materials was performed by SEM, FTIR, XRD, EDS and nitrogen adsorption/desorption analyses. In particular, there are significant changes in the capacitive response with the changes in the porous structure of the composite material with the addition of ZnO. In supercapacitor applications, the electrochemical properties of these electrode materials were investigated by CV, high charge/ discharge and EIS analyses. The maximum specific capacitances for the BPAC-S and ZnO-doped BPAC-S at 10 mA/g were 147.03 and 224.15 F/g.
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    Fabrication of nitrogen and ZnO doped on carbon particles obtained from waste biomass and their use as supercapacitor electrodes for energy storage
    (Pergamon-Elsevier Science Ltd, 2024) Saka, Cafer; Levent, Abdulkadir
    In this study, activated carbon (PPAC) is produced from pomegranate peel waste by activation of sodium hydroxide (NaOH) in the first stage. In the second stage, ammonia activation for nitrogen doping is carried out on PPAC (N-doped PPAC). In the third stage, zinc oxide (ZnO) doping is carried out on the obtained N-doped PPAC sample (ZnO@N-doped PPAC). The surface properties of the produced composite are examined by scanning electrode microscope (SEM), X-ray diffraction analysis (XRD), Energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy(XPS), micro Raman and nitrogen adsorption analyses. The electrochemical performance of the supercapacitor is investigated by cyclic voltammetry (CV), charge-discharge curves(GCD), and electrochemical impedance spectroscopy (EIS). N-doped PPAC and ZnO@Ndoped PPAC composite materials are used as supercapacitor electrodes. Specific capacitance values of 207.4 and 265.2 F/g in 1 M sulfuric acid(H2SO4) are obtained with N-doped PPAC and ZnO@N-doped PPAC electrodes, respectively. Additionally, cycle stability is achieved with a capacitance retention of approximately 86% after 5000 cycles at 0.6 A/g. The maximum energy density and power density of ZnO@N doped PPAC were calculated as 7.29 Wh/kg and 3600 Wh/kg, respectively.
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    High-performance pseudo-capacitance supercapacitor with highly mesoporous fluorine doped polymeric carbon nitride nanosheets as electrode material
    (Elsevier Science Sa, 2024) Saka, Cafer; Levent, Abdulkadir
    In this study, graphitic carbon nitride (GCN) material obtained from urea was hydrothermally doped with fluorine atoms (F-doped GCN). The resulting F-doped GCN material was designed as an electrode material for supercapacitors. Characterization of these samples was carried out by XRD, EDS, SEM, nitrogen adsorption and FTIR analyses. EDS and FTIR analyses confirmed the doping of fluorine atoms onto GCN. Nitrogen adsorption analyses supported the formation of a significant mesoporous structure with fluoride doping on GCN. The specific capacitance values of the GCN and F-doped GCN supercapacitors were calculated as 39.75 F/g and 305.72 F/g at a frequency of 0.01 Hz. A significant increase of about 7-fold in capacitance value was obtained by fluorine doping on GCN. Cycling trials of the F-doped GCN supercapacitor for up to 1000 cycles at a current density of 0.4 A/g maintain an efficiency of 86.72 %. For the supercapacitor designed from F-doped GCN material, the maximum energy density and power density were calculated as 4.26 Wh/kg and 1792 Wh/kg, respectively.
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    Mesoporous carbon particles by biomass waste based on sulfonation and copper oxide functionalization as efficient and stable electrode material for supercapacitor
    (Springer, 2024) Levent, Abdulkadir; Saka, Cafer
    Here, the hierarchical mesoporous-activated carbon particles obtained by KOH activation from pistachio shell wastes are modified by both the sulfonation process and CuO doping by hydrothermal heating (CuO@S-doped PSAC) for use as a supercapacitor. It is predicted that the electrochemical performance of the porous carbon electrode material obtained by such CuO doping and sulfonation process will be significantly increased with increased Faradaic capacitance. The electrochemical performance of CuO@S doped PSAC composite is systematically investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge/discharge (GCD) in the presence of 1 M H2SO4, 1 M Na2SO4, and 1 M NaOH as electrolytes. The CuO@S doped PSAC-based electrode shows excellent stability with high specific capacitance up to 397.16 F/g at 0.1 A/g and 92.64% retention. Furthermore, FTIR, SEM, XRD, EDS, and nitrogen adsorption/desorption analyses are used for the characterisation of the obtained composites. Based on a significant supercapacitor performance, the synthesis strategy of carbon-based electrode material containing sulfonation and CuO modifications derived from agricultural biomass waste material is predicted to be a valuable example. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
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    Stable electrode material for use in supercapacitor with iodine doping after sulfonation of mesoporous activated carbon particles based on microalgae biomass
    (2025-01-01) Levent, Abdulkadir; Saka, Cafer
    Developing appropriate electrode materials is crucial for achieving supercapacitors with high power output and extended cycle life. Among these, biomass-derived carbon electrodes hold a prominent position in supercapacitor applications. However, these electrodes need to be modified by appropriate methods to increase their performance. In this study, sulphur and iodine heteroatom functionalization was performed using a hydrothermal method on activated carbon (SPAC) derived from a microalgae precursor through potassium hydroxide activation, resulting in iodine- and sulphur-doped SPAC (iodine@S-doped SPAC). Characterization was carried out with Scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), energy-dispersive X-ray spectroscopy (EDS), and nitrogen adsorption/desorption analyses. The electrochemical properties of the resulting composite material as a supercapacitor were examined. A specific capacitance of 208.95 F/g was achieved with the iodine@S-doped SPAC supercapacitor. The maximum energy density and power density of the supercapacitor, derived from the iodine@S-doped SPAC sample, were calculated as 5.11 Wh/kg and 2000 W/kg, respectively. Additionally, the coulombic efficiency of this supercapacitor was calculated to be 87.57% at a current density of 0.06 A/g. It also exhibited a capacity retention of up to 89.72% over 1000 cycles.
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    Synthesis and characterization of 1,2-bis(2-(5-bromo-2-hydroxybenzilidenamino)-4-chlorophenoxy)ethane and its metal complexes: An experimental, theoretical, electrochemical, antioxidant and antibacterial study
    (Pergamon-Elsevier Science Ltd, 2014) Ilhan, Salih; Baykara, Haci; Oztomsuk, Abdussamet; Okumus, Veysi; Levent, Abdulkadir; Seyitoglu, M. Salih; Ozdemir, Sadin
    A new Schiff base ligand was synthesized by reaction of 5-bromosalicylaldehyde with 1,2-bis(4-chloro-2-aminophenoxy)ethane. Then the Schiff base complexes were synthesized by the reaction of metal salts and the novel Schiff base. The molar conductivity properties of the complexes were studied and found out that the complexes are nonelectrolytes. The structures of the ligand and its metal complexes were characterized by elemental analysis, FT-IR, UV-VIS, magnetic susceptibility measurements, molar conductivity measurements, and thermal gravimetric analysis. In addition antioxidant, theoretical NMR studies and cyclic voltammetry of the complexes were done. Two methods namely metal chelating activity and diphenylpicrylhydrazyl (DPPH) radical scavenging method were used to determine the antioxidant activity, and antibacterial properties of the compounds were also studied. (C) 2013 Elsevier B.V. All rights reserved.
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    Synthesis and characterization of 1,2-bis(2-(5-bromo-2-hydroxybenzilidenamino)-4-chlorophenoxy)ethane ant its metal complexes:An experimental, theoretical, electrochemical, antioxidant and antibacterial study
    (Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014) İlhan, Salih; Baykara, Haci; Tomsuk, Abdussamet; Okumuş, Veysi; Levent, Abdulkadir; Seyitoğlu, Salih; Özdemir, Sadin
    A new Schiff base ligand was synthesized by reaction of 5-bromosalicylaldehyde with 1,2-bis(4-chloro-2- aminophenoxy)ethane. Then the Schiff base complexes were synthesized by the reaction of metal salts and the novel Schiff base. The molar conductivity properties of the complexes were studied and found out that the complexes are nonelectrolytes. The structures of the ligand and its metal complexes were characterized by elemental analysis, FT-IR, UV–VIS, magnetic susceptibility measurements, molar conductivity measurements, and thermal gravimetric analysis. In addition antioxidant, theoretical NMR studies and cyclic voltammetry of the complexes were done. Two methods namely metal chelating activity and diphenylpicrylhydrazyl (DPPH) radical scavenging method were used to determine the antioxidant activity, and antibacterial properties of the compounds were also studied.
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    Synthesis and characterization of a new di-functional ligand and its metal complexes: an experimental, theoretical, cyclic voltammetric and antimicrobial study.
    (Synthesis and Reactivity in Inorganic, Metal-Organic & Nano Metal Chemistry, 2015) Baykara, Haci; İlhan, Salih; Tomsuk, Abdussamet; Seyitoğlu, Salih; Levent, Abdulkadir; Okumuş, Veysi; Dündar, Abdurrahman
    A new difunctional Schiff base ligand and its some metal complexes were synthesized. The compounds were characterized by elemental analysis, 1H-NMR, 13C-NMR, FT-IR, UV-VIS, magnetic susceptibility measurements, molar conductivity measurements, and thermal gravimetric analysis techniques. Additionally, DPPH scavenging, metal chelating and antibacterial activity of compounds were examined via in vitro methods. The lowest DPPH scavenging activity observed by Co(II) as 36.28% and highest was ligand as 52.00%. A cyclic voltammetric study was also carried out to determine redox potentials of the compounds. Some theoretical studies such as 1H-NMR, HOMO-LUMO, and mapped electron density of the ligand were also carried out successfully.
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    Synthesis and Characterization of a New Difunctional Ligand and Its Metal Complexes: An Experimental, Theoretical, Cyclic Voltammetric, and Antimicrobial Study
    (Taylor & Francis Inc, 2015) Baykara, Haci; Ilhan, Salih; Oztomsuk, Abdussamet; Seyitoglu, M. Salih; Levent, Abdulkadir; Okumus, Veysi; Dundar, Abdurrahman
    A new difunctional Schiff base ligand and its some metal complexes were synthesized. The compounds were characterized by elemental analysis, H-1-NMR, C-13-NMR, FT-IR, UV-VIS, magnetic susceptibility measurements, molar conductivity measurements, and thermal gravimetric analysis techniques. Additionally, DPPH scavenging, metal chelating and antibacterial activity of compounds were examined via in vitro methods. The lowest DPPH scavenging activity observed by Co(II) as 36.28% and highest was ligand as 52.00%. A cyclic voltammetric study was also carried out to determine redox potentials of the compounds. Some theoretical studies such as H-1-NMR, HOMO-LUMO, and mapped electron density of the ligand were also carried out successfully.
  • Küçük Resim
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    Synthesis, characterization and experimental, theoretical, electrochemical, antioxidant and antibacterial study of a new schiff base and its complexes
    (Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014) Baykara, Haci; İlhan, Salih; Levent, Abdulkadir; Seyitoğlu, Salih; Özdemir, Sadin; Okumuş, Veysi; Tomsuk, Abdussamet; Cornejo, Mauricio
    A new Schiff base ligand was synthesized by reaction of salicylaldehyde with 1,6-bis(4-chloro-2-aminophenoxy) hexane. Then the Schiff base complexes were synthesized by metal salts and the Schiff base. The metal to ligand ratio of metal complexes was found to be 1:1. The Cu(II) complex is proposed to be square planar and the Co(II), Ni(II), Mn(II) and Zn(II) complexes are proposed to be tetrahedral geometry. The Ti(III) and V(III) complexes are proposed to be a capped octahedron in which a seventh ligand has been added to triangular face. The complexes are non-electrolytes as shown by their molar conductivities (KM). The structure of metal complexes is proposed from elemental analysis, FT-IR, UV–vis, magnetic susceptibility measurements, molar conductivity measurements, Mass Spectra and thermal gravimetric analysis. In addition antimicrobial and antioxidant studies, cyclic voltammetry of the complexes, theoretical 1H NMR and HOMO–LUMO energy calculations of the new di-functional ligand were done.