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Article Citation - WoS: 7Citation - Scopus: 7Development of Non-Noble Co-N Electrocatalyst for High-Temperature Proton Exchange Membrane Fuel Cells(Pergamon-elsevier Science Ltd, 2020) Eren, Enis Oguzhan; Ozkan, Necati; Devrim, YilserThe development of a non-noble Co-N/MWCNT (MWCNT = multi-walled carbon nano tubes) electrocatalyst is achieved through the high-temperature pyrolysis method and successfully characterized by five-step physico-chemical analysis. By utilizing high resolution analytical surface characterization methods, the chemical states of elements are determined, and the presence of Co-N-x sites is confirmed. ORR activity of a Co-N/MWCNT is found to be auspicious. The maximum number of transferred-electron (n) and the diffusion-limiting current density (j(d)) are calculated as 3.95 and 4.53 mA.cm(-2), respectively. The catalyst is further evaluated under a single-cell test station. The test results show that the current and power density values of Co-N/MWCNT are found superior to those of the commercial Pt/C at the 150 degrees C and 160 degrees C (e.g., 57 vs. 69 mW.cm(-2) at 150 degrees C). Due to some stability issues, it is observed that the performance of the Co-N/MWCNT catalyst is slightly decreased while switching the temperature towards 180 degrees C. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Article Citation - WoS: 20Citation - Scopus: 26Polybenzimidazole-Modified Carbon Nanotubes as a Support Material for Platinum-Based High-Temperature Proton Exchange Membrane Fuel Cell Electrocatalysts(Pergamon-elsevier Science Ltd, 2021) Eren, Enis Oguzhan; Ozkan, Necati; Devrim, YilserWe fabricate polybenzimidazole (PBI) wrapped carbon nanotubes (MWCNTs) as support material for platinum-based fuel cell electrocatalyst. With the aid of microwave-assisted polyol reduction, we obtain very fine platinum (Pt) nanoparticles on PBI/MWCNT support while reducing the amount of Pt waste during synthesis. Cyclic voltammetry (CV) concludes that Pt-PBI/MWCNT has 43.0 m(2) g(-1) of electrochemically active surface area (ECSA) to catalyze hydrogen oxidation. Furthermore, after the 1000th cycle, Pt-PBI/MWCNT preserves almost 80% of its maximum ECSA, meaning that Pt-PBI/MWCNT is much more durable than the Pt/MWCNT and commercial Pt/C. High-temperature proton exchange membrane fuel cell (HT-PEMFC) performance tests are conducted under H-2/Air conditions at the temperatures ranging from 150 degrees C to 180 degrees C. Nevertheless, tests conclude that the maximum power density values of the Pt-PBI/MWCNT are found inferior to the Pt/C at all temperatures (e.g., 47 vs. 62 mW cm(-2) at 180 degrees C), suggesting that some balance between durability and performance has to be taken into consideration. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
