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    3D Polyoxometalate-Functionalized Graphene Quantum Dots with Mono-Metallic and Bi-Metallic Nanoparticles for Application in Direct Methanol Fuel Cells
    (Electrochemical Soc Inc, 2016) Colak, Alper Tolga; Eren, Tanju; Yola, Mehmet Lutfi; Besli, Erdem; Sahin, Onur; Atar, Necip
    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 throughoutworld. Afacile and cost-effective catalysts have been developed on polyoxometalate (NaPWO) functionalized graphene quantum dots (GQDs) with several mono-metallic and bi-metallic nanoparticles such as platinum nanoparticles (PtNPs), palladium nanoparticles (PdNPs) and platinum-palladium nanoparticles (Pt-PdNPs). 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), electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) method. According to TEM images, the average particle sizes of PtNPs and PdNPs were found to be approximately 20-30 nm. The Pt-PdNPs/NaPWO/GQDs also exhibited a higher peak current for methanol oxidation than those of comparable PdNPs/NaPWO/GQDs and PtNPs/NaPWO/GQDs, thus providing evidence for its higher electro-catalytic activity. (C) 2016 The Electrochemical Society. All rights reserved.
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    Öğe
    Sodium salt of boron-substituted first keggin-type polyoxometalate; synthesis, crystal structure and investigation of antimicrobial activities
    (Pergamon-Elsevier Science Ltd, 2025) Besli, Erdem; Colak, Ferdag; Sahin, Onur; Dikim, Selinsu; Colak, Alper Tolga
    This study aims to investigate the antimicrobial activity of the boron-containing polyoxometalate (BPOM) Na7[H1.5BW12O40]center dot 6en (1), synthesized as a single crystal. The structural and thermal properties of this novel BPOM were thoroughly analyzed using FT-IR, TGA, and X-ray diffraction (XRD) techniques. The incorporation of boron into these structures is believed to enhance their antimicrobial properties. The antimicrobial activity of the compound was evaluated against two Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus), three Gramnegative bacteria (Escherichia coli, Legionella spp., Legionella pneumophila sg 2-15), and a yeast (Candida albicans) using disc diffusion and tube dilution (Minimal Inhibition Concentration) methods. The results demonstrated that the synthesized compound exhibited significant antimicrobial activity, particularly against Bacillus cereus (Gram-positive) and Legionella spp. and Legionella pneumophila sg 2-15 (Gram-negative).