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    Öğe
    Evaluation of nanoparticle formation and magnetic properties by boron doping in Ni/NiO? nanoparticles
    (Springer, 2020) Adanur, Idris; Akyol, Mustafa; Tezcan, Fatih; Kardas, Gulfeza; Ekicibil, Ahmet
    In this work, Boron-doped B-x:Ni/NiO delta [x(%) = 0.0, 5.0, 10.0 and 15.0] core/shell magnetic nanoparticles were synthesized by the polyol reduction process. The XRD spectra of the samples indicate that the B addition does not cause any change in the cubic structure of Ni. The TEM photographs present that nanoparticle formation and accumulation orientation occurs in various shapes as spherical, octahedral-like and octopus-like accumulation. The average particle sizes of B-x:Ni/NiO(delta)MNPs forx(%) = 0.0, 5.0, 10.0, 15.0 were found as similar to 90, 12, 46, 5 nm, respectively, from the TEM images. It is observed from the temperature and magnetic field dependence magnetization measurements that magnetization of Ni/NiO delta core/shell MNPs increases with increasing Boron concentration from 5 to 15%. One can be deduced that this increment in the magnetization comes from the resulting of strengthening the Ni-B ferromagnetic interaction. The highest saturation magnetizations under 1 T magnetic field were found as similar to 37 and similar to 30 emu/g at 10 and 300 K, respectively.
  • [ X ]
    Öğe
    Production of Pt decorated poly(3,4-ethylenedioxythiophene)/ERGO/GCE as an efficient catalyst for methanol oxidation reaction
    (Wiley, 2023) Mert, Basak Dogru; Karazehir, Tolga; Mert, Mehmet Erman; Kardas, Gulfeza
    In this study, Pt-decorated poly(3,4-ethylenedioxythiophene) (PEDOT) electrocatalyst was uniformly coated electrochemically reduced graphene oxide (ERGO) layer on glassy carbon electrode (GCE) has been created using appropriate procedures to facilitate the implementation of the methanol oxidation reaction (MOR). This multi-layer catalyst was characterized in each production step via Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, field-emission scanning electron microscopy and energy-dispersive x-ray analysis (FESEM-EDX) morphological analysis beside the electrochemical tests. The favorable structures of both ERGO and PEDOT increase conductivity and electrocatalytic activity toward methanol oxidation, which may create a suitable matrix for Pt loading thanks to the formation of much more active centers for methanol electrooxidation. The results demonstrate that the electrochemical surface area (ECSA) of Pt/PEDOT/ERGO/GCE was 39.1 m(2) g(-1), and it has a convenient mass activity (MA with 467 mA mg Pt-1) compared to that of commercial Pt/C. According to chronoamperometric analysis, the current density of Pt/PEDOT/ERGO/GCE was stable during the 1200 s of operation. It demonstrated remarkable stability with a final current density of 4.36 mA cm(-2).