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Conference Object Citation - WoS: 98Citation - Scopus: 101Experimental Investigation of Co Tolerance in High Temperature Pem Fuel Cells(Pergamon-elsevier Science Ltd, 2018) Devrim, Yilser; Albostan, Ayhan; Devrim, HuseyinIn the present work, the effect of operating a high temperature proton exchange membrane fuel cell (HT-PEMFC) with different reactant gases has been investigated throughout performance tests. Also, the effects of temperature on the performance of a HT-PEMFC were analyzed at varying temperatures, ranging from 140 degrees C to 200 degrees C. Increasing the operating temperature of the cell increases the performance of the HT-PEMFC. The optimum operating temperature was determined to be 160 degrees C due to the deformations occurring in the cell components at high working temperatures. To investigate the effects of CO on the performance of HT-PEMFC, the CO concentration ranged from 1 to 5 vol %. The current density at 0.6 V decreases from 0.33 A/cm(2) for H-2 to 0.31 A/cm(2) for H-2 containing 1 vol % CO, to 0.29 A/cm(2) for 3 vol % CO, and 0.25 A/cm(2) for 5 vol % CO, respectively. The experimental results show that the presence of 25 vol % CO2 or N-2 has only a dilution effect and therefore, there is a minor impact on the HT-PEMFC performance. However, the addition of CO to H-2/N-2 or H-2/CO2 mixtures increased the performance loss. After longterm performance test for 500 h, the observed voltage drop at constant current density was obtained as similar to 14.8% for H-2/CO2/CO (75/22/3) mixture. The overall results suggest that the anode side gas mixture with up to 5 vol % CO can be supplied to the HT-PEMFC stack directly from the reformer. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - WoS: 85Citation - Scopus: 92Enhancement of Pem Fuel Cell Performance at Higher Temperatures and Lower Humidities by High Performance Membrane Electrode Assembly Based on Nafion/Zeolite Membrane(Pergamon-elsevier Science Ltd, 2015) Devrim, Yilser; Albostan, AyhanThis work reports the preparation of Nafion/zeolite composite membranes with different zeolite loading. The structure of the Nafion/zeolite composite membranes are investigated by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and by thermogravimetric analysis (TGA). The introduction of zeolite particles into the Nafion matrix helps to improve the water uptake, proton conductivity and thermal stability of the nanocomposite membranes compared to the virgin Nafion membrane. The SEM analyses have proved the uniform and homogeneous distribution of zeolite in composite membranes. The composite membranes are tested in a single PEMFC with a 5 cm(2) active area operating at the temperature range of 75-120 degrees C and in humidified under 50% relative humidity (RH) and fully humidified conditions. Single PEMFC tests show that Nafion/zeolite composite membrane is more stable and also performed better than virgin Nafion membrane at low humidity condition. The results indicate the Nafion/zeolite composite membranes could be utilized as the proton exchange membranes for PEMFC. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Article Citation - WoS: 18Citation - Scopus: 20Cobalt nanoparticles supported on alumina nanofibers (Co/Al2O3): Cost effective catalytic system for the hydrolysis of methylamine borane(Pergamon-elsevier Science Ltd, 2019) Baguc, Ismail Burak; Yurderi, Mehmet; Bulut, Ahmet; Celebi, Metin; Kanberoglu, Gulsah Saydan; Zahmakiran, Mehmet; Baysal, AkinAmongst different amine-borane derivatives, methylamine-borane (CH3NH2BH3) seems to be one of the capable aspirants in the storing of hydrogen attributable to its high hydrogen capacity, stability and aptitude to generate hydrogen through its catalytic hydrolysis reaction under ambient conditions. In this research paper, we report that cobalt nano-particles supported on alumina nanofibers (Co/Al2O3) are acting as active nanocatalyst for catalytic hydrolysis of methylamine-borane. Co/Al2O3 nanocatalyst was fabricated by double-solvent method followed with wet-chemical reduction, and was characterized by utilizing various spectroscopic methods and imaging techniques. The results gathered from these analyses showed that the formation Al2O3 nanofibers supported cobalt(0) nanoparticles with a mean diameter of 3.9 +/- 1.2 nm. The catalytic feat of these cobalt nanoparticles was scrutinized in the catalytic hydrolysis of methylamine-borane by considering their activity and durability performances. They achieve releasing of 3.0 equivalent of H-2 via methylamine-borane hydrolysis at room temperature (initial TOF = 297 mol H-2/mol metal x h). Along with activity the catalytic durability of Co/Al2O3 was also studied by carrying out recyclability tests and it was found that these supported cobalt nanoparticles have good durability during the course of the catalytic recycles so that Co/Al2O3 preserves almost its innate activity at 5th catalytic recycle. The studies presented here also contains kinetic investigation of Co/Al2O3 catalyzed methylamine borane hydrolysis depending on the temperature, cobalt and methylamine borane concentrations, which were used to define rate expression and the activation energy of the catalytic reaction. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
