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Article Citation - WoS: 19Citation - Scopus: 21Development of Effective Bimetallic Catalyst for High-Temperature Pem Fuel Cell To Improve Co Tolerance(Wiley, 2021) Al-Tememy, Mogdam Gassy Hussein; Devrim, YilserIn this study, it is aimed to examine the effect of multi-walled carbon nanotube doped graphene nanoplatelet (MWCNT-GNP) supported PtPd bimetallic catalyst on the performance of the high-temperature proton-exchange membrane fuel cell (HT-PEMFC). In addition, PtPd/GNP and PtPd/MWCNT bimetallic catalysts were also investigated for performance comparison. The characterizations of these catalysts were examined by ICP-MS, XRD, HR-TEM, and TGA analysis. The electrochemical characterizations of the catalysts were performed for both cyclic voltammetry (CV) and CO stripping experiments, as well as HT-PEMFC tests. The specific surface area (SSA) for PtPd/GNP and PtPd/MWCNT catalysts was obtained as 148 and 137 m(2)/g, respectively, while the highest SSA was achieved as 164 m(2)/g for PtPd/MWCNT-GNP. The performance of the catalysts was confirmed with the HT-PEMFC tests, based on the H-2/air and reformate gas/air experiments. The electrocatalytic results display that PdPt bimetallic catalysts exhibited higher catalytic property than that of commercial Pt/C catalyst. The highest performance was achieved with PtPd/MWCNT-GNP catalyst as 0.390 and 0.310 W/cm(2)at 160 degrees C for H-2/air and reformat/air, respectively. The obtained results indicate that the PtPd/MWCNT-GNP catalyst is appropriate for HT-PEMFC operations.Article Citation - WoS: 21Citation - Scopus: 21Investigation 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, YagmurIn 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.Article Citation - WoS: 9Citation - Scopus: 10Investigation of the Performance of High-Temperature Electrochemical Hydrogen Purification From Reformate Gases(Wiley, 2022) Durmus, Gizem Nur Bulanik; Durmuş, Gizem Nur Bulanık; Colpan, C. Ozgur; Devrim, Yilser; Devrim, Yılser; Durmuş, Gizem Nur Bulanık; Devrim, Yılser; Mechanical Engineering; Energy Systems Engineering; Mechanical Engineering; Energy Systems EngineeringIn the present work, the purification of hydrogen from a hydrogen/carbon dioxide/carbon monoxide (H-2:CO2:CO) mixture by a high-temperature electrochemical purification (HT-ECHP) system is examined. Electrochemical H-2 purification experiments were carried out in the temperature range of 140-180 degrees C. The effects of the molar ratio of the gases in the mixture (H-2:CO2:CO-75:25:0, H-2:CO2:CO-72:26:2,0 H-2:CO2:CO-75:22:3, H-2:CO2:CO-75:20:5, H-2:CO2:CO-97:0:3, H-2:CO2:CO-95:0:5) and the operating temperature on the electrochemical H-2 separation were investigated. As a result of the electrochemical H-2 purification experiments, it was determined that the operating temperature is the most important parameter affecting the performance. According to the results obtained, H-2 purity of 99.999% was achieved at 160 degrees C with the reformate gas mixture containing 72% H-2, 26% CO2, and 2% CO by volume. According to the polarization curves of the gas mixtures containing CO, high current densities at low voltage were reached at 180 degrees C, and it was observed that the performance increased as the temperature increased, whereas the gas mixture without CO gave the best performance at 160 degrees C.Article Citation - WoS: 5Citation - Scopus: 9Development and Performance Analysis of Polybenzimidazole/Boron Nitride Composite Membranes for High-Temperature Pem Fuel Cells(Wiley, 2022) Hussin, Dedar Emad; Budak, Yagmur; Devrim, YilserIn this research, polybenzimidazole/boron nitride (PBI/BN) based composite membranes have been prepared for high-temperature PEM fuel cell (HT-PEMFC). BN was preferred because of its superior thermal robustness, high chemical stability, non-conductor property, and high plasticizer characteristic. The loading of BN in the composite membrane was studied between 2.5 to 10 wt%. The composite membranes were characterized using TGA, DSC, XRD, SEM, mechanical tests, acid doping/leaching, and proton conductivity measurements. The highest conductivity of 0.260 S/cm was found for PBI/BN-2.5 membrane at 180 degrees C. It has been determined that the PBI/BN-2.5 membrane has higher performance than the PBI membrane according to the HT-PEMFC tests performed with Hydrogen and dry air. The heightened HT-PEMFC performance can be ascribed to interactive effects between BN particles and the PBI polymer matrix. PBI/BN composite membranes show a good perspective in the high-temperature PEMFC applications.Article Citation - WoS: 9Citation - Scopus: 10Evaluation of Hybridsolar-Wind System Based on Methanol Electrolyzer(Wiley, 2020) Budak, Yagmur; Devrim, YilserIn this study, it is aimed to meet the annual electricity and heating needs of a house without interruption with the photovoltaic panel, wind turbine, methanol electrolyzer, and high temperature proton exchange membrane fuel cell system. The system results show that the use of the 2 WT with 18 PV was enough to provide the need of the methanol electrolyzer, which provides requirements of the high temperature proton exchange membrane fuel cell. The produced heat by the fuel cell was used to meet the heat requirement of the house with combined heat and power system. Electrical, thermal and total efficiencies of fuel cell system with combined heat and power were obtained as 38.54%, 51.77% and 90%, respectively. Additionally, the levelized cost of energy of the system was calculated as 0.295 $/kWh with combined heat and power application. The results of this study show that H(2)is useful for long-term energy storage in off-grid energy systems and that the proposed hybrid system may be the basis for future H-2-based alternative energy applications.Article Citation - WoS: 26Citation - Scopus: 27Performance of an Ht-Pemfc Having a Catalyst With Graphene and Multiwalled Carbon Nanotube Support(Wiley, 2019) Alpaydin, Guvenc Umur; Devrim, Yilser; Colpan, C. OzgurIn this study, the effect of multiwalled carbon nanotube and graphene nanoplatelet-based catalyst supports on the performance of reformate gas-fed polybenzimidazole (PBI)-based high-temperature proton exchange membrane fuel cell (HT-PEMFC) was investigated. In addition, the effect of several microwave conditions on the performance of the Pt-Ru/multiwalled carbon nanotube (MWCNT)-graphene nanoplatelet (GNP) catalyst was assessed. Through X-ray diffraction, thermal gravimetric analysis, transmission electron microscopy, scanning electron microscopy, and energy dispersive spectroscopy, the catalysts' chemical structure and morphology were characterized. Cyclic voltammetry analysis was used for the electrochemical characterization of catalysts through an electrochemical cell with three electrodes connected to a potentiostat. The results showed that the best performing catalyst is the catalyst produced using 800-W power for 40 seconds. The electrochemically active surface area values of this catalyst ranged from 54 to 45 m(2)/g. Single-cell performance tests of the HT-PEMFC were then carried out. In these tests, reformate gas mixture, consisting of H-2, CO2, and CO, was fed to the anode side at 160 degrees C without humidification. These tests for the best performing catalyst yielded peak power density of 0.280 W/cm(2) and current density (at 0.6 V) of 0.180 A/cm(2) in the H-2/air environment and peak power density of 0.266 W/cm(2) and current density (at 0.6 V) of 0.171 A/cm(2) in the reformate gas/air environment. As a result of the experiments, it was found that Pt-Ru/MWCNT-GNP hybrid material is a suitable catalyst for HT-PEMFC.Article Citation - WoS: 4Citation - Scopus: 6Statistics and Probability Theory in Renewable Energy: Teaching and Research(Wiley, 2023) Eryilmaz, Serkan; Kateri, Maria; Devrim, YilserIn this paper, the key-role and utility of statistics and probability theory in the field of renewable energy are emphasized and illustrated via specific examples. It is demonstrated that renewable energy is a very suitable field to effectively teach and implement many statistical and probabilistic concepts and techniques. From a research point of view, statistical and probabilistic methods have been successfully employed in evaluating renewable energy systems. These methods will continue to be of core interest for the renewable energy sector in the future, as new and more complex renewable energy systems are developed and installed. In this context, some future research directions in relation to the evaluation of renewable energy systems are also presented.
