Yazar "Şahin, Ö." seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • [ X ]
    Öğe
    Al2 o3 supported co-cu-b (Co-cu-b/al2 o3 ) catalyst for hydrogen generation by hydrolysis of aqueous sodium borohydride (nabh4 ) solutions
    (S.C. Virtual Company of Phisics S.R.L, 2019) Baytar, O.; İzgi, M.S.; Horoz, S.; Şahin, Ö.; Nar, S.
    In this study, Al2O3 supported Co-Cu-B (Co-Cu-B/Al2O3 ) catalyst was synthesized by chemical impregnation and precipitation method to be used for catalytic hydrogen generation from NaBH4. Co-Cu-B/Al2O3 catalyst was synthesized at various ratios using Co-Cu-B/Al2O3 (5-20%). The effect of some parameters such as NaOH concentration (0-7%), NaBH4 concentration (2.5-7.5%), catalyst amount (25-150 mg) and solution ambient temperature was investigated on the catalytic hydrolysis of NaBH4. The hydrogen generation rate was found as 2519 and 8962 mL*g-1 *min-1 for Co-Cu-B and Co-Cu-B/Al2O3 catalysts in NaBH4 hydrolysis, respectively. The order rate kinetics and activation energy for Co-Cu-B/Al2 O3 catalyst were determined as 0.125 and 27 kJ*mol-1, respectively. The obtained results suggest that Co-Cu-B/Al2O3 catalysts can be used for mobile applications of PEMFC systems. © S.C. Virtual Company of Phisics S.R.L. All rights reserved.
  • [ X ]
    Öğe
    Effect of Ce doping on the characteristic properties of CdS nanoparticles
    (S.C. Virtual Company of Phisics S.R.L, 2020) Ekinci, A.; Horoz, S.; Şahin, Ö.
    In our present study, Ce doped CdS nanoparticles were synthesized in room temperature environment by using chemical co-precipitation technique which is cheap in cost. Ce doped CdS nanoparticles (average particle size: 3.7 nm) were found to have cubic structure as a result of XRD measurements. It has also been clearly observed that Ce dopant ions do not alter the structure of the host semiconductor CdS. Using the spectrum obtained as a result of UV-Vis measurement, the energy band gap of Ce doped CdS nanoparticles was determined as 2.73 eV. This value was observed to be higher than the energy band gap of bulk CdS (2.42 eV). Thus, it can be said that this change in the energy band gap is due to the quantum confinement effect. The maximum IPCE value was 27% for Ce doped CdS nanoparticles while the IPCE values was 4% for pure CdS nanoparticles, respectively. The IPCE of the solar cells improves with the Ce dopant ion. Moreover, the spectral response range of Ce doped CdS nanoparticles widens with the Ce dopant ion. This is attributed to the long lifetimes of the Ce3+ excited states that facilities the transfer of the charge carries to the photoelectrode. © 2020, S.C. Virtual Company of Phisics S.R.L. All rights reserved.
  • [ X ]
    Öğe
    Hydrogen generation from NaBH 4 solution with the high-performance Co(0) catalyst using a cold plasma method
    (Taylor and Francis Inc., 2014) Şahin, Ö.; Hansu, F.; Saka, C.; Baytar, O.
    The hydrogen production from the hydrolysis of NaBH4 with Co(0) catalyst, which is prepared with a cold plasma method under nitrogen atmosphere, was investigated with effects of NaBH4 and NaOH concentration, temperature, plasma applying time and applying power, and Co(0) catalyst effect. The hydrolysis reaction completed within around 10-min time intervals with cold plasma, while the hydrolysis reaction in the known method completed within around 20-min time intervals. The completion rate of hydrolysis reaction with Co(0) catalyst in cold plasma media compared to non-plasma media increased to be around 100%. The yield of hydrogen in the presence of 3.2, 10, and 25% NaBH4 solution takes the values of around 94, 90, and 15% at the end of 600 sec, respectively. The experimental data were fitted to first-order. The activation energy for first-order was found to be 26.02 kJ mol-1. © 2014 Taylor & Francis Group,LLC.
  • [ X ]
    Öğe
    Studies on catalytic behavior of co–cr–b/al2 o3 in hydrogen generation by hydrolysis of nabh4
    (S.C. Virtual Company of Phisics S.R.L, 2019) Izgi, M.S.; Baytar, O.; Şahin, Ö.; Horoz, S.
    In this present study, the chemical reduction technique was used to synthesize Al2O3 supported Co-Cr-B catalyst (Co-Cr-B/Al2O3). The effects of the concentration of NaBH4, NaOH, amount of catalyst, ratio of metal/ Al2 O3and temperature were discussed in detail. The results show that the reaction rate of hydrolysis first rises up and then goes down subsequently with the increase of NaBH4 concentration, as well as the concentration of NaOH. It was observed that the hydrogen generation rate increases with the molar content of metal changing from 2.5% to 5 wt%. However, when the metal/Al2O3 molar ratio is located from 5% to 20 wt%, the rate of hydrogen generation goes down. The hydrolysis kinetic order and the activation energy (EE ) of NaBH4 in the presence of Co-Cr-B/Al2O3 catalyst were found as 0.15 and 37.34 kJ*mol-1, respectively. According to the results obtained, Co-Cr-B/Al2O3 catalyst can be used as a promising material in PEMFC mobile systems. © 2019, S.C. Virtual Company of Phisics S.R.L. All rights reserved.
  • [ X ]
    Öğe
    Synthesis of activated carbon in the presence of hydrochar from chickpea stalk and its characterization
    (S.C. Virtual Company of Phisics S.R.L, 2021) Genli, N.; Şahin, Ö.; Baytar, O.; Horoz, S.
    In this study, hydrochar was obtained from chickpea stalk by hydrothermal method. Then, activated carbon was synthesized by chemical activation method using ZnCl2 activator in the presence of this hydrochar. The effects of parameters such as impragnation rate (hydrochar/ZnCl2), impragnation rate, activation temperature and activation time on activated carbon synthesis were investigated. The iodine number of the obtained activated carbon was determined and its characterization was performed by SEM, BET, FTIR measurements. It was determined that the highest iodine number of synthesized activated carbon was 734 mg/g under conditions of impragnation time (24 hour), impragnation rate (1/2), activation temperature (400oC), and activation time (45 minutes). The BET surface area of the activated carbon with the highest iodine number was determined as 572 m2/g. The methylene blue number of synthesized activated carbon and hydrochar were found as 105 mg/g and 45 mg/g, respectively. © 2021, S.C. Virtual Company of Phisics S.R.L. All rights reserved.
  • [ X ]
    Öğe
    Synthesis of an efficient photocatalyst (Activated carbon supported zns) for methylene blue degradation
    (S.C. Virtual Company of Phisics S.R.L, 2020) Zörer, C.; Baytar, O.; Şahin, Ö.; Horoz, S.; Izgi, M.S.
    In the present study, activated carbon (AC) supported ZnS catalysts at different concentrations of AC were synthesized using hydrothermal method. The MB photocatalytic degradation efficiency of AC supported ZnS catalysts at different concentrations of AC was examined in the presence of UV-C lamp. As a result of photocatalytic measurements, the catalyst having the best photocatalytic activation was determined. The effect of different parameters, such as the amount of catalyst and dye concentration, on the photocatalytic degradation of methylene blue was investigated in the presence of this catalyst.Moreover, The photocatalytic degradation kinetics of methylene blue in the presence of catalyst were investigated by first and second order kinetic model. In the last part of the study, structural, morphological and elemental properties of the catalyst having the best photocatalytic activity were examined by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray (EDX)measurements, respectively. © 2020, S.C. Virtual Company of Phisics S.R.L. All rights reserved.
  • [ X ]
    Öğe
    Synthesis zto nanoparticles and study of their photocatalytic properties
    (S.C. Virtual Company of Phisics S.R.L, 2019) Bulut, N.; Baytar, O.; Şahin, Ö.; Horoz, S.
    Nanosized zinc tin oxide (ZTO, Zn2SnO4) photocatalysts were prepared with a hydrothermal technique and their structural and optical properties were characterized by performing powder x-ray diffraction (XRD), ultraviolet-visible (UV-Vis) and photoluminescence (PL) spectroscopies, respectively. The XRD results indicated that the ZTO nanoparticles have a face-centered cubic spinel structure and the average crystallite size was calculated as 18.75 nm by using the Debye–Scherrer equation. The band gap of ZTO nanoparticles was determined as 3.87 eV which is higher than that of bulk ZTO (3.6 eV). The effect of some parameters (amount of dye, amount of catalyst and temperature) were studied on the photocatalytic activity of ZTO nanoparticles. The obtained all results revealed that ZTO nanoparticles can be used as promising photocatalysts for degradation methyl-blue (MB) (dye). Moreover, it was determined that photocatalytic degradation kinetics of dye at all temperatures are better matched to the first order kinetic model. © 2019, S.C. Virtual Company of Phisics S.R.L. All rights reserved.