Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 7A Comprehensive Life Cycle Impact Evaluation of Hydrogen Production Processes for Cleaner Applications(Pergamon-elsevier Science Ltd, 2025) Goren, A. Yagmur; Dincer, Ibrahim; Khalvati, AliThe worldwide energy demands have greatly increased with urbanization and population growth. Air pollution, acid rain, greenhouse gas emissions, global warming originating from CO2 emissions, depletion of energy supplies, and environmental degradation resulting from climate change are all consequences of using non-renewable fossil fuel-based energy infrastructure. To minimize emissions, renewable energy-based alternative energy sources must be investigated. In this regard, hydrogen (H2) has emerged as a promising fuel to meet energy requirements, and green H2 production with net-zero emissions has gained significant interest in recent years. Therefore, this study uses the life cycle assessment approach to evaluate the atmospheric emissions and environmental impact parameters of the gasification, electrolysis, and dark fermentation-microbial electrolysis hybrid process and assess their sustainability levels, considering the sustainable development goals. Among the studied H2 production processes, the maximum CO2 emission originates from the coal gasification process, accounting for 18.6 kg-CO2/kg-H2, while the alkaline electrolysis process provides the lowest total CO2 emission of 6.39 kg-CO2/kg-H2. Furthermore, the biological-based dark fermentation-microbial electrolysis cell process is a promising option owing to its highest negative biogenic CO2 emission of -68.69 kg-CO2/kg-H2. The environmental impact parameters of the studied processes are calculated considering the emissions, and the highest global warming potential of 21.75 kgCO2-eq./kg-H2 is obtained for the coal gasification process, considering the life cycle assessment coefficients. Overall, the lowest atmospheric emissions and environmental impacts are obtained for the electrolysis process. Consequently, these results revealed that switching from the fossil fuel resources used in the conventional H2 production methods to fully sustainable sources, such as renewables, can make energy production methods entirely sustainable from an environmental point of view.Article Citation - WoS: 10Citation - Scopus: 10The Role of Effective Catalysts for Hydrogen Production: a Performance Evaluation(Pergamon-elsevier Science Ltd, 2025) Goren, A. Yagmur; Temiz, Mert; Erdemir, Dogan; Dincer, IbrahimIn recent years, research on hydrogen (H2) production for alternative and environmentally-benign energy solution as fuel, storage medium and feedstock has been one of the most highly demanded subjects. It aims to reduce the pressures set by carbon dioxide emissions and the depletion of fossil fuel supplies. Nevertheless, largescale H2 production is limited by its high cost and low yield. The distinct photo-electrochemical characteristics of catalysts have shown them to have great promise for enhancing the production of H2. This article presents an updated and comprehensive review of enhanced H2 production using various catalysts in biological, thermochemical, and water-based processes. Various operational parameters (reactor configuration, catalyst dosage, catalyst type, catalyst modification methods, temperature, pH, and inoculum type) are summarized to improve the H2 production performance and reduce the environmental impacts and costs of these processes. For instance, in dark fermentation, biological H2 production is enhanced by 3.2-38 % with certain metal catalysts. Overall, results revealed that catalysts, specifically inorganic catalysts such as iron, nickel, titanium oxide, and silver, have improved the production rate of H2. This review has provided the application fields and working principles of catalysts in different H2 production processes. Finally, we suggested the main concerns that need to be prioritized in the long-term advancement of H2 production using catalysts.Article Citation - WoS: 7Citation - Scopus: 7Hydrogen Production From Energetic Poplar and Waste Sludge by Electrohydrogenesis Using Membraneless Microbial Electrolysis Cells(Pergamon-elsevier Science Ltd, 2024) Goren, A. Yagmur; Kilicaslan, A. Faruk; Dincer, Ibrahim; Khalvati, AliMembraneless microbial electrolysis cells (MECs) are potentially considered to produce biohydrogen (bioH2) in a green manner and simultaneously minimize agricultural and wastewater facility wastes. However, effective, sustainable, and cost-effective system configuration and improvement of operating variables, working at ambient conditions, are needed to make the MEC a sustainable process. Therefore, this study investigates the bioH2 production from poplar leaves and anaerobic sludge mixture by incorporating nanomaterials comprising Al2O3, MgO, and Fe2O3 metal oxides at various dosages. Moreover, the effects of applied cell voltage (0.5-1.5 V) and inoculum amount (20-40 mL) on bioH2 production and organic matter removal performance are evaluated. The maximum bioH2 production value is 417 mL at an applied voltage of 1.5 V with a chemical oxygen demand (COD) removal efficiency of 37.6 % under operating times of 5 min using 40 ml of inoculum. The bioH2 production of the MEC system is reduced with the decrease in inoculum amount. The highest bioH2 production of 828 mL is obtained at improved conditions in the presence of 1 g of Fe2O3 metal oxide. Overall, this study provides the potentiality of simultaneous waste minimization and bioH2 production under ambient conditions that highlight the waste-to-energy pathway for membraneless and green bioelectrochemical process.