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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: 15Citation - Scopus: 15Optimal Design and Technoeconomic Analysis of On-Site Hydrogen Refueling Station Powered by Wind and Solar Photovoltaic Hybrid Energy Systems(Pergamon-elsevier Science Ltd, 2025) Ozturk, Reyhan Atabay; Devrim, YilserIn this study, a grid-connected on-site hydrogen filling station (HRS) integrated with renewable energy systems is designed and examined for different daily hydrogen refueling capacities. The installation location of the HRS is selected in Izmir (Turkey) and daily solar radiation and wind speed data are used in the calculations. The HRS station was integrated with a hybrid energy system using photovoltaic panels (PV), wind turbine (WT) and PV/ WT and five different daily refueling scenarios were investigated. A techno-economic analysis is conducted for the designed HRS system, considering the initial investment capital, installation and operating costs. The levelized cost of hydrogen (LCOH) is evaluated according to different refueling capacity scenarios, periods of operation and renewable energy installation capacities. The lowest LCOH is obtained as 4.5 /kg H2 in the PVintegrated HRS system for a 20-year investment scenario. The results prove the suitability of the HRS system for integrating renewable energy in the identified region. It is recommended to integrate analytical models for the system components to increase the reliability of the design and optimization process in future planned studies.Article Mathematical Modeling of a Direct Dimethyl Ether Fuel Cell(Wiley-hindawi, 2022) Alpaydin, Guvenc Umur; Durmus, Gizem Nur Bulanik; Colpan, C. Ozgur; Devrim, YilserIn this study, a mathematical model of a direct dimethyl ether fuel cell (DDMEFC) is developed to examine the effect of operating conditions on voltage losses and cell performance. In modeling, the electrochemical relations and mass balances are used to find the cell voltage for the given conditions. The values of some modeling parameters are determined using experimental data through curve fitting. For validation purposes, in-house experimental studies are conducted. For this purpose, Pt50Ru25Pd25/C, Pt40Ru40Pd20/C, and Pt50Pd50/C anode catalysts are synthesized by the microwave method. The effects of these synthesized catalysts and the operating conditions (cell temperature, the molar ratio of dimethyl ether, and water) on the DDMEFC performance are discussed by comparing the activation and ohmic polarization as well as the polarization curves using the model developed. This cell-level modeling approach could be considered as a preliminary step in the design process of a DDMEFC stack.Article Citation - WoS: 44Citation - Scopus: 45Carbon Nanotube-Graphene Supported Bimetallic Electrocatalyst for Direct Borohydride Hydrogen Peroxide Fuel Cells(Pergamon-elsevier Science Ltd, 2021) Uzundurukan, Arife; Akca, Elif Seda; Budak, Yagmur; Devrim, YilserAt present study, carbon nanotube-graphene (CNT-G) supported PtAu, Au and Pt catalysts were prepared by microwave-assisted synthesis method to investigate the direct liquid-fed sodium borohydride/hydrogen peroxide (NaBH4/H2O2) fuel cell performance. Prepared catalysts were characterized by TGA, XRD, TEM, ICP-OES, cyclic voltammetry and rotating disc electrode (RDE) voltammetry. The catalysts were tested in a single NaBH4/H2O2 fuel cell with 25 cm(2) active area to evaluate fuel cell performance. The effects of temperature and fuel concentration on fuel cell performance were examined to observed best operating conditions. As a result of direct NaBH4/H2O2 fuel cell experiments, maximum power densities of 139 mW/cm(2), 125 mW/cm(2) and 113 mW/cm(2) were obtained for PtAu/CNT-G, Au/CNT-G and Pt/CNT-G catalysts, respectively. PtAu/CNT-G catalyst showed the enhanced NaBH4/H2O2 fuel cell performance, which was higher than the Pt/CNT-G catalyst and Au/CNT-G catalyst at 50 degrees C. The enhanced NaBH4/H2O2 performance can be attributed to synergistic effects between Pt and Au particles on CNT-G support providing a better catalyst utilization and interaction. These results suggest that the prepared PtAu/CNT-G catalyst is a promising anode catalyst for NaBH4/H2O2 fuel cell application. (c) 2020 Elsevier Ltd. All rights reserved.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: 3Citation - Scopus: 4The Design and Techno-Economic Evaluation of Wind Energy Integrated On-Site Hydrogen Fueling Stations for Different Electrolyzer Technologies(Pergamon-Elsevier Science Ltd, 2025) Devrim, Yilser; Ozturk, Reyhan AtabayHydrogen refueling stations (HRS) integrated with renewable energy sources present a pivotal solution for achieving sustainable transportation systems. This study focuses on the design and techno-economic analysis of a grid-connected, on-site hydrogen production HRS powered by wind energy, incorporating various electrolyzer technologies. The selected location for the HRS installation is & Ccedil;anakkale, Turkey, where daily wind speed data has been utilized for performance calculations. The proposed HRS system integrates a wind turbine (WT) with three different electrolyzer technologies: alkaline electrolyzer (AEL), proton exchange membrane electrolyzer (PEMEL), and anion exchange membrane electrolyzer (AEMEL). A comprehensive techno-economic analysis was conducted to evaluate the system's performance, considering factors such as initial capital investment, installation, operation, and replacement costs. The results of the analysis reveal that the levelized cost of hydrogen (LCOH) varies between 9.0 and 18.7 /kg H2, depending on the type of electrolyzer technology used and the daily hydrogen refueling capacity. Notably, increasing the hydrogen refueling capacity significantly reduces production costs. The minimum LCOH of 9.0 /kg H2, achieved under a 20-year investment scenario, corresponds to a refueling capacity of 250 kg H2/day when utilizing the AEL-integrated HRS system. The findings underscore the economic feasibility of on-site hydrogen refueling stations powered by wind energy and utilizing AEL, AEMEL, and PEMEL systems. Among the systems analyzed, the AEL-based HRS system demonstrated the highest return on investment (ROI) of 13.02 % and the shortest payback period (PBP) of 7.7 years, highlighting its economic performance. This study provides valuable insights into the integration of renewable energy with hydrogen production infrastructure, emphasizing the potential of wind-powered HRS systems to advance the sustainability and economic viability of hydrogen-based transportation solutions.Article Citation - WoS: 64Citation - Scopus: 69Reliability and Optimal Replacement Policy for a k-out-of-n< System Subject To Shocks(Elsevier Sci Ltd, 2019) Eryilmaz, Serkan; Devrim, YilserConsider a k-out-of-n system which is subject to shocks that occur at random times. Each shock causes failure of random number of components, and hence the system's lifetime corresponds to one of the arrival times of shocks. The reliability and mean time to failure of the system are studied when the times between shocks follow a phase type distribution. The optimal replacement time problem which is concerned with the minimization of the total long-run average cost per unit time is also defined and studied.Article Citation - WoS: 2Citation - Scopus: 2Performance Assessment of Anion Exchange Electrolyzer With PBI-BASED Membrane Through 0-D Modeling(Elsevier Ltd, 2025) Celebi, Ceren; Colpan, C. Ozgur; Devrim, YilserAnion exchange membrane (AEM) water electrolysis is emerging as a promising method for the sustainable production of hydrogen. A key advantage lies in the potential for cost-effective hydrogen production by substituting expensive noble metal electrocatalysts with affordable transition metals. This work presents a 0-D mathematical model for evaluating the performance of AEMWEs, with a particular focus on polybenzimidazole (PBI)-based membranes, which are renowned for their high thermal stability, chemical resistance and excellent conductivity in alkaline media. The objective of the model is to predict the behavior of membranes in AEMWE systems, and it has been employed to evaluate the performance of a range of PBI membranes. To ensure precision, the values were meticulously selected from the literature, in accordance with the experimental conditions. Furthermore, IR-corrected validation was incorporated to isolate the impact of membrane conductivity on performance, thereby facilitating a dependable assessment of PBI membranes under diverse conditions. The model considers the effects of electrolyte resistance and bubble formation on cell voltage behavior. The efficiency was evaluated on the basis of the higher heating value (HHV). The findings demonstrate that one membrane exhibits consistent efficiency across a broad temperature range (40-90 degrees C), whereas the other displays notable variability under diverse conditions. In particular, the efficiency of the electrolyzer is significantly enhanced by the use of thinner membranes and higher temperatures. The highest efficiencies obtained were 83.9% and 79.8% for 25 mu m and 50 mu m PBI/Polystyrene membrane under the operating conditions of 1 M KOH solution at 80 degrees C and current density of 2 A/cm2. This study aims to provide valuable information on the performance of PBI membranes through a zero-dimensional model validated by experimental data.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.
