Petrol ve Doğalgaz MühendisliğiPetrol and Natural Gases Engineeringhttps://hdl.handle.net/20.500.12508/1272024-03-28T11:27:12Z2024-03-28T11:27:12ZHigh-Performance Ag-Doped Na0.67MnO2 Cathode: Operando XRD Study and Full-Cell Performance Analysis with Presodiated AnodeKalyoncuoğlu, BurcuÖzgül, MetinAltundağ, SebahatAltın, EmineMoeez, IqraChung, Kyung YoonArshad, MuhammadAydın, Mustafa GöktanDepci, TolgaAltın, SerdarŞahinbay, Sevdahttps://hdl.handle.net/20.500.12508/30242024-01-17T11:48:08Z2023-01-01T00:00:00ZHigh-Performance Ag-Doped Na0.67MnO2 Cathode: Operando XRD Study and Full-Cell Performance Analysis with Presodiated Anode
Kalyoncuoğlu, Burcu; Özgül, Metin; Altundağ, Sebahat; Altın, Emine; Moeez, Iqra; Chung, Kyung Yoon; Arshad, Muhammad; Aydın, Mustafa Göktan; Depci, Tolga; Altın, Serdar; Şahinbay, Sevda
The key challenges of Na-ion batteries are to design structurally stable electrodes and reach high-enough capacities with full-cells. In this study, we report the positive effects of Ag substitution/addition to Na0.67MnO2. We determined that some of the intended Ag was incorporated into the structure, while the rest remained in metallic form. Ag substitution/addition increases the capacity (208 mA h/g at C/3 rate) and improves the cycle life of Na0.67MnO2 (42% capacity fade with 100 cycles) in half-cells. We attribute these results to an enlarged interlayer spacing due to the large ionic radius of Ag, a suppressed Jahn-Teller effect due to the reduced number of Mn3+ ions, and an increased electrical conductivity due to the presence of metallic Ag. We also produced full-cells with an electrochemically presodiated hard carbon anode. We reached a very high initial capacity of 190 mA h/g at the C/3 rate, showing that Ag substituted/added Na0.67MnO2 is a promising candidate for commercialization of Na-ion batteries.
2023-01-01T00:00:00ZCatalytic cracking of gas oil derived from heavy crude oil over biochar-based catalystKar, YakupKök, Onur Eserhttps://hdl.handle.net/20.500.12508/30192024-01-17T06:36:15Z2023-01-01T00:00:00ZCatalytic cracking of gas oil derived from heavy crude oil over biochar-based catalyst
Kar, Yakup; Kök, Onur Eser
In this study, the main target is to obtain high grade light commercial motor fuels from the catalytic cracking of the gas oil fraction by using a modified green catalyst biochar. For this aim, initially the biochar has been impregnated with the spent pickling liquor to acquire a catalyst being strong cracking activity under certain conditions. By using of the catalyst activated via the spent pickling liquor, the catalytic cracking runs have been carried out on the gas oil at different catalyst additive rates in ranging from 5 wt.% to 20 wt.% to obtain light liquid hydrocarbon fractions at the temperature of 500oC and heating rate of 10 ℃/min. The n-pentane soluble fraction of the catalytic cracking liquid obtained from the use of activated char catalyst at additive rate of 20 wt.% has a low sulphur content and also consisted of short straight chain paraffinic hydrocarbons with carbon number of C13, C17, and C18 compared to those of the thermal and non-activated catalyst. Consequently, the activated catalyst has a considerable potential as a green catalyst with low cost for the converting of heavy hydrocarbons into light and more valuable hydrocarbons.
2023-01-01T00:00:00ZCatalytic pyrolysis of lignite with clay catalyst activated with spent pickling liquorKar, YakupMert, Bayram Alihttps://hdl.handle.net/20.500.12508/30002024-01-15T08:23:52Z2023-01-01T00:00:00ZCatalytic pyrolysis of lignite with clay catalyst activated with spent pickling liquor
Kar, Yakup; Mert, Bayram Ali
Spent pickling liquor (SPL) is an acidic waste with rich iron content from the stainless steel production industry. Reusability of SPL as a catalytic activity promoter in bentonite clay is crucial for the catalytic pyrolysis of various materials like biomass, coal, and waste plastics. For this aim, the bentonite catalyst activated with the SPL nomenclatured as SPL-treated bentonite (SPLAB) catalyst was employed in the catalytic pyrolysis of lignite for an oil product with high yield and quality. The SPL-treated bentonite catalytic pyrolysis oil (SPLABO) for the conditions of the final temperature of 600°C, heating rate of 10°C/min, and catalyst ratio of 15 wt% had a yield of 26.35 ± 1.14 wt% and good fuel properties in view of the higher heating value of 35.23 MJ/kg and density of 1076.4 kg/m3 at 20°C. Moreover, it has a rich chemical content by means of monocyclic aromatics and shorter chain alkanes compared with that of the thermal activated bentonite oil (TABO). Based on the chemical structure analysis results of the SPLABO and TABO comparatively, it was concluded that the SPL agent used as a catalytic activity promoter led to a significant increase in the catalytic activity of bentonite catalyst.
2023-01-01T00:00:00ZNovel data on genotoxic assessment of bismuth sulfide nanoflowers in common carp Cyprinus carpioErgenler, AyşegülTuran, FundaZaman, Buse TuğbaTezgin, EmineBakırdere, SezginDepci, Tolgahttps://hdl.handle.net/20.500.12508/29842024-01-12T11:07:11Z2023-01-01T00:00:00ZNovel data on genotoxic assessment of bismuth sulfide nanoflowers in common carp Cyprinus carpio
Ergenler, Ayşegül; Turan, Funda; Zaman, Buse Tuğba; Tezgin, Emine; Bakırdere, Sezgin; Depci, Tolga
The environmental impacts and risks of nanomaterials that are commonly used in different technologies are of great concern as their toxic effects on the aquatic ecosystem remain unclear. In this study, bismuth sulfide (Bi2S3) nanoflowers (nfs) were synthesized using a microwave-based hydrothermal process, and their genotoxic effects were investigated in the common carp, Cyprinus carpio. Bi2S3 nanoflowers were applied to common carp for 96 h. LC50 value (LC50 = 350 mg/L−1) was determined for acute toxicity with probit analysis, and three sublethal concentrations (35, 87, and 175 mg/L−1) were selected accordingly for genotoxicity tests. Such LC50 value − 350 mg L−1 for the common carp makes these nanoflowers non-toxic to aquatic organisms according to the EU-Directive 93/67/EEC classification scheme. Toxicological evaluations of the sublethal concentrations of Bi2S3 nanoflowers demonstrated that the 35 and 87 mg L−1 Bi2S3nfs groups were generally harmless and similar to the control group. Only the 175 mg L−1 Bi2S3nfs group had significant DNA damage frequency and nuclear abnormalities than the control and other Bi2S3nfs groups. To the best of our knowledge, this is a novel data on genotoxicity reported for fish species exposed to Bi2S3 nanoflowers; however, further systematic studies need to be performed to fully estimate the effects of Bi2S3 nanoflowers on aquatic life.
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