Browsing by Author "Uzundurukan, Arife"

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Citation Count: 34
Carbon nanotube-graphene hybrid supported platinum as an effective catalyst for hydrogen generation from hydrolysis of ammonia borane
(Pergamon-elsevier Science Ltd, 2019) Uzundurukan, Arife; Devrim, Yilser; Energy Systems Engineering
In this study, we report the results of a kinetic study on the hydrogen (H-2) generation from the hydrolysis of ammonia borane (NH3BH3) catalyzed by Platinum supported on carbon nanotube-graphene hybrid material (Pt/CNT-G). Synthesized catalyst was characterized by TGA, XRD, CP-OES, TEM and SEM-EDX techniques. Characterization studies have shown that the CNT-G hybrid support material provides desired distribution of the Pt particles on the support material. The effect of various parameters such as catalyst loading, reaction temperature, effect of NaOH and the effect of NH3BH3 concentration are also determined. Experimental results showed that the Pt/CNT-G catalyst exhibited high catalytic activity on NH3BH3 hydrolysis reaction to release H-2. It has been found that Pt/CNT-G catalyst shows low activation energy of 35.34 kJ mol(-1) for hydrolysis reaction of NH3BH3. Pt/CNT-G catalyst also exhibited high catalytic activity with turnover frequency (TOF) of 135 (mol(H2)/mol(cat).-min). Therefore, the synthesized Pt/CNT-G catalyst is a potential candidate for enhanced H-2 generation through NH3BH3 hydrolysis. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation Count: 24
Carbon nanotube-graphene supported bimetallic electrocatalyst for direct borohydride hydrogen peroxide fuel cells
(Pergamon-elsevier Science Ltd, 2021) Uzundurukan, Arife; Akca, Elif Seda; Budak, Yagmur; Devrim, Yilser; Energy Systems Engineering
At present study, carbon nanotube-graphene (CNT-G) supported PtAu, Au and Pt catalysts were prepared by microwave-assisted synthesis method to investigate the direct liquid-fed sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell performance. Prepared catalysts were characterized by TGA, XRD, TEM, ICP-OES, cyclic voltammetry and rotating disc electrode (RDE) voltammetry. The catalysts were tested in a single NaBH4/H2O2 fuel cell with 25 cm(2) active area to evaluate fuel cell performance. The effects of temperature and fuel concentration on fuel cell performance were examined to observed best operating conditions. As a result of direct NaBH4/H2O2 fuel cell experiments, maximum power densities of 139 mW/cm(2), 125 mW/cm(2) and 113 mW/cm(2) were obtained for PtAu/CNT-G, Au/CNT-G and Pt/CNT-G catalysts, respectively. PtAu/CNT-G catalyst showed the enhanced NaBH4/H2O2 fuel cell performance, which was higher than the Pt/CNT-G catalyst and Au/CNT-G catalyst at 50 degrees C. The enhanced NaBH4/H2O2 performance can be attributed to synergistic effects between Pt and Au particles on CNT-G support providing a better catalyst utilization and interaction. These results suggest that the prepared PtAu/CNT-G catalyst is a promising anode catalyst for NaBH4/H2O2 fuel cell application. (c) 2020 Elsevier Ltd. All rights reserved.
Citation Count: 36
Examination of compression effects on PEMFC performance by numerical and experimental analyses
(Pergamon-elsevier Science Ltd, 2020) Uzundurukan, Arife; Bilgili, Muhittin; Devrim, Yilser; Energy Systems Engineering
In the present study, the effects of compression method on Proton Exchange Membrane Fuel Cell (PEMFC) performance were investigated both numerically and experimentally. Total deformation of the components within the PEMFC was simulated by ANSYS threedimensional finite element analysis (3D FEA). Moreover, geometrical and material properties of all components of PEMFC such as bipolar plates (BPP), membrane electrode assembly (MEA), gasket, current collector plate (CCP), screw and nut were implemented for accurate simulation of compression. In the experimental part, PEMFC tests were performed with 25 cm(2) active area single cell having 3 channel parallel in series (3 PS) flow channel via PEMFC test station with H-2 and air at 60 degrees C. The maximum power density was achieved as 0.458 W/cm(2) and 0.480 W/cm(2) for bolt compression and clamping plates compression, respectively. The equivalent stress values were found as 120 MPa that under 4389 N the clamping plates and 1600 MPa under bolt compression with 1.3 Nm torque. When numerical and experimental studies are examined together, it is seen that bolt compression has higher deformation and less equivalent stress than clamping plates compression. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation Count: 44
Hydrogen generation from sodium borohydride hydrolysis by multi-walled carbon nanotube supported platinum catalyst: A kinetic study
(Pergamon-elsevier Science Ltd, 2019) Uzundurukan, Arife; Devrim, Yilser; Energy Systems Engineering
In this study, it is aimed to investigate hydrogen (H-2) generation from sodium borohydride (NaBH4) hydrolysis by multi-walled carbon nanotube supported platinum catalyst (Pt/MWCNT) under various conditions (0-0.03 g Pt amount catalyst, 2.58-5.03 wt % NaBH4, and 27-67 degrees C) in detail. For comparison, carbon supported platinum (Pt/C) commercial catalyst was used for H-2 generation experiments under the same conditions. The reaction rate of the experiments was described by a power law model which depends on the temperature of the reaction and concentrations of NaBH4. Kinetic studies of both Pt/MWCNT and Pt/C catalysts were done and activation energies, which is the required minimum energy to overcome the energy barrier, were found as 27 kJ/mol and 36 kJ/mol, respectively. Pt/ MWCNT catalyst is accelerated the reaction less than Pt/C catalyst while Pt/MWCNT is more efficient than Pt/C catalyst, they are approximately 98% and 95%, respectively. According to the results of experiments and the kinetic study, the reaction system based on NaBH4 in the presence of Pt/MWCNT catalyst can be a potential hydrogen generation system for portable applications of proton exchange membrane fuel cell (PEMFC). (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation Count: 10
Investigation of hydrogen production from sodium borohydride by carbon nano tube-graphene supported PdRu bimetallic catalyst for PEM fuel cell application
(Wiley, 2022) Al-Msrhad, Tuqa Majeed Hameed; Devrim, Yilser; Uzundurukan, Arife; Budak, Yagmur; Energy Systems Engineering
In this study, hydrogen (H-2) generation from the hydrolysis of sodium borohydride (NaBH4) catalyzed by bimetallic Palladium-Ruthenium (PdRu) supported on multiwalled carbon nanotube-graphene (MWCNT-GNP) hybrid material is investigated. The effect of various parameters such as temperature, NaBH4 concentration, and catalyst loading and effect of base concentration are examined to observed optimum operating conditions. Experimental results show that the PdRu/MWCNT-GNP bimetallic catalyst has high catalytic activity on NaBH4 hydrolysis reaction. It has been found that PdRu/MWCNT-GNP catalyst shows low activation energy of 22.33 kJ/mol for hydrolysis reaction of NaBH4. The PdRu/MWCNT-GNP catalyst also exhibits H-2 generation rate of 79.2 mmol/min center dot g(cat) at 45 degrees C. It shows good cycle stability in the catalyst reusability test and retained 89% of its initial catalytic activity after fifth use. The high catalytic activity of the PdRu/MWCNT-GNP catalyst makes it promising in H-2 generation from NaBH4 hydrolysis for commercial proton exchange membrane fuel cell (PEMFC) applications.