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Conference Object Citation - WoS: 82Citation - Scopus: 92Graphene Based Catalyst Supports for High Temperature Pem Fuel Cell Application(Pergamon-elsevier Science Ltd, 2018) Devrim, Yilser; Arica, Elif Damla; Albostan, AyhanIn this study, the effect of graphene nanoplatelet (GNP) and graphene oxide (GO) based carbon supports on polybenzimidazole (PBI) based high temperature proton exchange membrane fuel cells (HT-PEMFCs) performances were investigated. Pt/GNP and Pt/GO catalysts were synthesized by microwave assisted chemical reduction support. X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Brauner, Emmet and Teller (BET) analysis and high resolution transmission electron microscopy (HRTEM) were used to investigate the microstructure and morphology of the as-prepared catalysts. The electrochemical surface area (ESA) was studied by cyclic voltammetry (CV). The results showed deposition of smaller Pt nanoparticles with uniform distribution and higher ECSA for Pt/GNP compared to Pt/GO. The Pt/GNP and Pt/GO catalysts were tested in 25 cm(2) active area single HT-PEMFC with H-2/air at 160 degrees C without humidification. Performance evaluation in HT-PEMFC shows current densities of 0.28, 0.17 and 0.22 A/cm(2) for the Pt/GNP, Pt/C and Pt/GO catalysts based MEAs at 160 degrees C, respectively. The maximum power density was obtained for MEA prepared by Pt/GNP catalyst with H-2/Air dry reactant gases as 0.34, 0.40 and 0.46 W/cm(2) at 160 degrees C, 175 degrees C and 190 degrees C, respectively. Graphene based catalyst supports exhibits an enhanced HT-PEMFC performance in both low and high current density regions. The results indicate the graphene catalyst support could be utilized as the catalyst support for HT-PEMFC application. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Conference Object Citation - WoS: 52Citation - Scopus: 61Multi-Walled Carbon Nanotubes Decorated by Platinum Catalyst for High Temperature Pem Fuel Cell(Pergamon-elsevier Science Ltd, 2019) Devrim, Yilser; Arica, Elif DamlaIn the literature, studies on platinum catalysts deposited on multi-walled carbon nanotube (Pt/MWCNT) have been mostly focused on low temperature fuel cell (LT-PEMFC) applications. In this study, we focus the synthesis and characterization of high temperature fuel cell (HT-PEMFC) performance of Pt/MWCNT in short and long term. The structural properties of the Pt/MWCNT electrocatalyst were analyzed by XRD, TGA, SEM and TEM measurements. The Pt/MWCNTs were also characterized by electrochemical measurements for durability estimation. Laboratory scale MEA with Pt/MWCNT was prepared by ultrasonic coating technique and has been tested in situ in single HT-PEMFC. Performance curves in dry Hydrogen/Air system were obtained that demonstrated performance comparable to commercial catalysts in that HT-PEMFC. The characterizations specified that the electrocatalytic and HT-PEMFC performance of the Pt/MWCNT catalysts are higher power density (0.360 W/cm(2)) than Pt/C (0.310 W/cm(2)) at 160 degrees C. The results obtained show that the synthesized catalysts are suitable for high temperature applications. In addition, the stability studies of MEAs prepared with Pt/MWCNT catalyst were performed by AST tests and compared with Pt/C based MEA. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation - WoS: 37Citation - Scopus: 41Carbon 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, YilserIn 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.Article Citation - WoS: 60Citation - Scopus: 64Hydrogen Generation From Sodium Borohydride Hydrolysis by Multi-Walled Carbon Nanotube Supported Platinum Catalyst: a Kinetic Study(Pergamon-elsevier Science Ltd, 2019) Uzundurukan, Arife; Devrim, YilserIn 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.
