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COAR Access Rights: metadata only accessSubject: Graphene oxide

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    Conference Object
    Citation - WoS: 82
    Citation - Scopus: 92
    Graphene Based Catalyst Supports for High Temperature Pem Fuel Cell Application
    (Pergamon-elsevier Science Ltd, 2018) Devrim, Yilser; Arica, Elif Damla; Albostan, Ayhan
    In 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.
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    Article
    Citation - WoS: 159
    Citation - Scopus: 172
    Development of Polybenzimidazole/Graphene Oxide Composite Membranes for High Temperature Pem Fuel Cells
    (Pergamon-elsevier Science Ltd, 2017) Uregen, Nurhan; Pehlivanoglu, Kubra; Ozdemir, Yagmur; Devrim, Yilser
    In this study, phosphoric acid doped Polybenzimidazole/Graphene Oxide (PBI/GO) nano composite membranes were prepared by dispersion of various amounts of GO in PBI polymer matrix followed by phosphoric acid doping for high temperature proton exchange membrane fuel cell (HT-PEMFC) application. The structure of the PBI/GO composite membranes was investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and by thermogravimetric analysis (TGA). The introduction of GO into the FBI polymer matrix helps to improve the acid doping, proton conductivity and acid leaching properties. The SEM analyses have proved the uniform and homogeneous distribution of GO in composite membranes. The composite membranes were tested in a single HT-PEMFC with a 5 cm(2) active area at 165 degrees C without humidification. HT-PEMFC tests show that PBI/ GO composite membrane with 2 wt. % GO content performed better than bare PBI membrane at non humidified condition. At ambient pressure and 165 degrees C, the maximum power density of the PBI/GO-1 membrane can reach 0.38 W/cm(2), and the current density at 0.6 V is up to 0.252 A/cm(2), with H-2/air. The results indicate the PBI/GO composite membranes could be utilized as the proton exchange membranes for HT-PEMFC. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.