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    A novel determination of curcumin via Ru@Au nanoparticle decorated nitrogen and sulfur-functionalized reduced graphene oxide nanomaterials
    (Royal Soc Chemistry, 2016) Kotan, Gul; Kardas, Faruk; Yokus, Ozlem Aktas; Akyildirim, Onur; Saral, Hasan; Eren, Tanju; Yola, Mehmet Lutfi
    We report the synthesis of Ru@Au nanoparticle involved L-cysteine functionalized reduced graphene oxide (rGO) composites (NSrGO/Ru@AuNPs). The nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The electrochemical determination of curcumin (CR) has been studied using square wave voltammetry (SWV) on a glassy carbon electrode (GCE) modified with NSrGO/Ru@AuNP composites (NSrGO/Ru@AuNPs/GCE). The effective surface areas (ESAs) of the rGO/GCE and NSrGO/Ru@AuNPs/GCE were calculated to be 347 cm(2) mg(-1) and 1289 cm(2) mg(-1), respectively. These results show that the electrochemical surface area of the NSrGO/Ru@AuNPs/GCE is 3.71 times higher than that of the rGO/GCE. The developed method was also applied successfully for the determination of CR in plasma and the linearity range of CR was 0.001-0.1 nM with a detection limit of 2.0 x 10(-13) M.
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    Electrochemical Sensor Based on Graphene Oxide/Iron Nanoparticles for the Analysis of Quercetin
    (Esg, 2015) Akyildirim, Onur; Medetalibeyoglu, Hilal; Manap, Sevda; Beytur, Murat; Tokali, Feyzi Sinan; Yola, Mehmet Lutfi; Atar, Necip
    We aimed a novel electrochemical sensor based on iron nanoparticles (FeNPs) and 2-aminoethanethiol (2-AET) functionalized graphene oxide (2-AETGO). The methods such as transmission electron microscope (TEM), scanning electron microscope (SEM), x-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIRS), electrochemical impedance spectroscopy (EIS) and the x-ray diffraction (XRD) method were used for the characterizations of nanocomposites. The linearity and the detection limit of quercetin (QR) were 1.0x10(-8) - 1.0x10(-7) M and 2.0x10(-9) M, respectively. The modified glassy carbon electrode (FeNPs/2-AETGO/GCE) was applied to the determination of QR in food sample such as apple juice.
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    Fabrication of bimetallic Pt/Pd nanoparticles on 2-thiolbenzimidazole functionalized reduced graphene oxide for methanol oxidation
    (Springer Heidelberg, 2016) Akyildirim, Onur; Kotan, Gul; Yola, Mehmet Lutfi; Eren, Tanju; Atar, Necip
    In this study, an electrocatalyst based on 2-thiolbenzimidazole (TBI) functionalized reduced graphene oxide (rGO) with platinum and palladium nanoparticles (Pt-PdNPs) was synthesized. The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope, X-ray photo electron spectroscopy, scanning electron microscope, electrochemical impedance spectroscopy and X-ray diffraction method. The effective surface areas of TBIrGO/GCE, PdNPs/TBIrGO/GCE, PtNPs/TBIrGO/GCE and Pt-PdNPs/TBIrGO/GCE were calculated to be 324, 578, 667 and 1189 cm(2)/mg, respectively. According to the results, the electrochemical surface area of the Pt-PdNPs/TBIrGO is 3.67, 2.06 and 1.78 times higher than those of TBIrGO, PdNPs/TBIrGO and PtNPs/TBIrGO, respectively. The Pt-PdNPs/TBIrGO/GCE also exhibited higher peak current for methanol oxidation than those of comparable TBIrGO/GCE, PdNPs/TBIrGO/GCE, PtNPs/TBIrGO/GCE modified GCEs, thus providing evidence for its higher electro-catalytic activity.
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    Platinum nanoparticles involved on nitrogen and sulfur-doped nanomaterial as fuel cell electrode
    (Springer, 2017) Saral, Hasan; Akyildirim, Onur; Yuksek, Haydar; Eren, Tanju
    A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions, and environmental pollution throughout world. In this study, a facile and cost-effective catalysts have been developed on platinum nanoparticles (PtNPs) supported on nitrogen and sulfur-doped nanomaterial (PtNPs-NS). The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope (TEM), X-ray photo electron spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. According to TEM images, the average particle sizes of PtNPs were found to be approximately 20-25 nm. The effective surface areas of NS/GCE and PtNPs-NS/GCE were calculated to be 105 and 518 cm(2)/mg, respectively. The PtNPs-NS/GCE also exhibited a higher peak current for methanol oxidation than those of comparable GCE and NS/GCE, providing evidence for its higher electro-catalytic activity.
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    Platinum nanoparticles supported on nitrogen and sulfur-doped reduced graphene oxide nanomaterial as highly active electrocatalysts for methanol oxidation
    (Springer, 2016) Akyildirim, Onur; Yuksek, Haydar; Saral, Hasan; Ermis, Ismail; Eren, Tanju; Yola, Mehmet Lutfi
    A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions and environmental pollution throughout world. In this study, a facile and cost-effective catalysts have been developed on platinum nanoparticles (PtNPs) supported on nitrogen and sulfur-doped reduced graphene oxide (NSrGO). The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope (TEM), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS). According to TEM images, the average particle sizes of PtNPs were found to be approximately 15-20 nm. The effective surface areas (ESA) of NSrGO/GCE and PtNPs/NSrGO/GCE were calculated to be 148 and 469 cm(2)/mg, respectively. The PtNPs/NSrGO/GCE also exhibited a higher peak current for methanol oxidation than those of comparable GCE and NSrGO/GCE, providing evidence for its higher electro-catalytic activity.
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    Sensitive voltammetric sensor based on polyoxometalate/reduced graphene oxide nanomaterial: Application to the simultaneous determination of L-tyrosine and L-tryptophan
    (Elsevier Science Sa, 2016) Yokus, Ozlem Aktas; Kardas, Faruk; Akyildirim, Onur; Eren, Tanju; Atar, Necip; Yola, Mehmet Lutfi
    In this report, a novel voltammetric sensor based on polyoxometalate (H3PW12040, POM) functionalized reduced graphene oxide (rGO) modified glassy carbon electrode (GCE) was presented for simultaneous determination of L-tyrosine (L-Tyr) and L-tryptophan (L-Trp). The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrochemical determination of L-Tyr and L-Trp has been studied using square wave voltammetry (SWV) on GCE modified with POM-rGO composite (POM-rGOIGCE). The developed method was also applied successfully for the simultaneous determination of L-Tyr and L-Trp in spiked serum sample and the linearity range of L-Tyr and L-Trp was 1.0 x 10(-11) - 1.0 x 10(-9)M with the detection limit of 2.0 x 10(-12)M. (C) 2016 Elsevier B.V. All rights reserved.