Yazar "Gurbet Canpolat" seçeneğine göre listele

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  • Küçük Resim
    Öğe
    Applications of Environmentally Friendly Metal Oxides as PEM Fuel Cell Cathode Catalysts
    (Springer Science and Business Media LLC, 2025-04-10) Orhan Baytar; Ömer Şahin; Abdurrahman Akdag; Gurbet Canpolat; Arzu Ekinci
    For the first time, this study investigated the behaviors of CuO and FeO metal oxides synthesized from bean shell extract using an environmentally friendly green synthesis method at varying cell temperatures in PEMFCs according to the amount of Pt used. Analyzed techniques such as XRD, SEM–EDX, TEM, and XPS were used to ascertain the structural and morphological characteristics of the produced catalysts. The performance of the catalysts was evaluated based on the voltage-current density values obtained from PEMFCs at different cell temperatures and increased at higher cell temperatures.At a cell temperature of 70 °C, the Pt-FeO/C and Pt-CuO/C catalysts exhibited higher power values than the Pt/FeO-C and Pt/CuO-C catalysts, containing only half the amount per unit area. The power density values for catalysts were tested as follows: 3380 mW/cm2mgPt for Pt-FeO/C, 1697 mW/cm2mgPt for Pt-CuO/C, 919 mW/cm2mgPt for Pt/FeO-C, and 1264 mW/cm2mgPt for Pt/CuO-C, and these values were determined to be higher than the values measured using the Pt/C (431 mW/cm2mgPt) catalyst. According to the measured current density-power density values, It was determined that the performances of the catalysts were Pt/FeO-C > Pt-CuO/C > Pt/CuO-C > Pt-FeO/C.
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    Bio-derived catalysts for hydrogen production: Synthesis, characterization, and performance
    (Elsevier BV, 2025-03) Arzu Ekinci; Ömer Şahin; Gurbet Canpolat; Orhan Baytar
    In this study, green synthesis method was used to prepare Co–La–B catalysts using Rheum ribes bark extract as stabilizing agent. SEM, EDX, XRD, FTIR, TEM and XPS analyses determined the structural and morphological properties of the Co–La–B catalyst. The average particle size was found to be about 30 nm, indicating a high surface area, which can enhance the catalytic activity. In addition, the presence of functional groups in the shell extract was confirmed, suggesting their role in stabilizing the metal particles during synthesis. The particle size was determined to be 20–50 nm in TEM analysis results. For the first time, green synthesis of Co–La–B catalyst using Rheum ribes bark extract was carried out and the effect of different NaOH/NaBH4 concentrations, different amounts of catalyst and temperature on sodium borohydride hydrolysis was studied. In the study, the cycle frequency (TOF) values for Co–La–B catalyst at different temperatures were determined to be 31610 mLH2/gcat.min. Activation energy (Ea), activation entropy (ΔS) and activation enthalpy (ΔH) values were calculated as 62.61 kJ/mol, −120 J/molK and 29.82 kJ/mol, respectively. Reusability tests determined the efficiency of the nanoparticle as 89.4 %.
  • Küçük Resim
    Öğe
    Cost-Effective Removal of Cu(II) and Cd(II) from Wastewater Using Walnut Shell-Immobilized Amberlite XAD-4 as a Sorbent
    (Springer Science and Business Media LLC, 2025-05-19) İbrahim Teğin; Selma Akdeniz; Gurbet Canpolat; Orhan Acar
    In this study, a cost-effective and environmentally friendly solid-phase extraction (SPE) method using walnut shell-immobilised on Amberlite XAD-4 (WNS-XAD-4) was developed to pre-concentrate and determine Cu(II) and Cd(II) ions in water samples prior to flame atomic absorption analysis (FAAS). The low-cost adsorbent, prepared by immobilizing waste walnut shells on Amberlite XAD-4 (WNS-XAD-4), was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA), and Brunauer-Emmett-Teller (BET) analysis. Under optimal conditions, the method achieved recoveries of 95.7% for Cu(II) and 100% for Cd(II) using 5.0 mL of 1.5 mol L-1 HNO3 as eluent. The detection limits were found as 0.582 mu g L-1 for Cu(II) and 0.03 mu g L-1 for Cd(II) with preconcentration factors of 10 and 40, respectively. The accuracy of the method was validated using the certified aquatic plant reference material BCR-670 and successfully applied to various real water samples, including those from Lake Van, Billoris Spa, tap water, salt water and wastewater from Siirt, Turkey.