Materials Science and Engineering / Malzeme Bilimi ve Mühendisliği

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Breaking the Boundaries of the Goldschmidt Tolerance Factor With Ethylammonium Lead Iodide Perovskite Nanocrystals
    (American Chemical Society, 2024) Güvenç, Çetin Meriç; Toso, Stefano; Ivanov, Yurii P.; Saleh, Gabriele; Balcı, Sinan; Divitini, Giorgio; Manna, Liberato
    We report the synthesis of ethylammonium lead iodide (EAPbI3) colloidal nanocrystals as another member of the lead halide perovskites family. The insertion of an unusually large A-cation (274 pm in diameter) in the perovskite structure, hitherto considered unlikely due to the unfavorable Goldschmidt tolerance factor, results in a significantly larger lattice parameter compared to the Cs-, methylammonium- and formamidinium-based lead halide perovskite homologues. As a consequence, EAPbI3 nanocrystals are highly unstable, evolving to a nonperovskite delta-EAPbI3 polymorph within 1 day. Also, EAPbI3 nanocrystals are very sensitive to electron irradiation and quickly degrade to PbI2 upon exposure to the electron beam, following a mechanism similar to that of other hybrid lead iodide perovskites (although degradation can be reduced by partially replacing the EA+ ions with Cs+ ions). Interestingly, in some cases during this degradation the formation of an epitaxial interface between (EA x Cs1-x )PbI3 and PbI2 is observed. The photoluminescence emission of the EAPbI3 perovskite nanocrystals, albeit being characterized by a low quantum yield (similar to 1%), can be tuned in the 664-690 nm range by regulating their size during the synthesis. The emission efficiency can be improved upon partial alloying at the A site with Cs+ or formamidinium cations. Furthermore, the morphology of the EAPbI3 nanocrystals can be chosen to be either nanocube or nanoplatelet, depending on the synthesis conditions.
  • Article
    Citation - Scopus: 4
    One-step hydrothermal synthesis of spinel manganese oxide ion-sieve from commercial Γ-Mno2 and its uptake performance for lithium
    (Elsevier Ltd, 2024) Toprak, Seyra; Demir, Mustafa Muammer
    The selective extraction of lithium from aqueous systems necessitates efficient sorbent materials. Spinel-type lithium manganese oxide ion sieves (LMOs) have been bee recognized for their high performance in this application. However, the elevated market cost of the spinel form (λ-MnO2) raises economic concerns, posing challenges to the feasibility of the extraction process. In this study, the one-step hydrothermal synthesis of Li1.33Mn1.67O4 was carried out at 200 °C for 7 days using commercial γ-MnO2 powder and aqueous LiOH solution as reactants. The synthesized powder exhibited characteristic XRD reflections consistent with spinel Li1.33Mn1.67O4. Lithium ion-sieve (H1.33Mn1.67O4) was obtained by leaching the LMO product with dilute hydrochloric acid solution. The sorption capacity of γ-MnO2 is increased from 8.4 to 23.1 mg/g (C0=200 mg/L), this capacity is very close to the one of the commercial λ-MnO2. The synthesized spinel HMO sorbent achieved a maximum Langmuir adsorption capacity of 52.1 mg/g. The extraction efficiency reached 94% at the sorbent dose of 20 g/L. The distribution coefficients of metal ions were in the order Li+ > Ca2+ > K+ > Na+, emphasizing selective Li+ extraction from brines with high Na+ content. These findings highlight the successful development of a spinel-type lithium manganese oxide ion sieve from γ-MnO2 polymorph, which is nearly an order of magnitude cheaper than the selective λ-MnO2. The study addresses critical issue of economic feasibility in lithium extraction processes, providing a potential solution for the selective recovery of bulk lithium. © 2024 Elsevier Ltd
  • Article
    Citation - Scopus: 1
    Audio-magnetotelluric (amt) studies over rajapur hot spring in west coast maharashtra, India
    (indian Acad Sciences, 2024) Deshmukh, Vasu; Kumar, P. V. Vijaya; Chandrasekaram, D.; Raju, Khasi; Sathishkumar, S.; Srinivas, Y.; Rao, P. B. V. Subba
    In the west coast geothermal provinces, the Rajapur hot spring, located in the southern part of western Maharashtra, is well thought to originate from the interaction of meteoric water with the granitic basement. A 3D AMT survey was conducted to determine the geo-electrical structure of the hot spring. Dimensionality analysis carried out by phase tensor analysis reveals complex subsurface 3D structures. 2D and 3D modelling have yielded three distinct resistivity layers in the Rajapur geothermal field. These layers include a moderately resistive surface layer representing weathered Deccan traps having a thickness of about 100 m, a conductive second layer with a thickness of about 100-400 m represents Kaladgi sediments and a deeper high resistive layer (0.5-1.0 km) representing granitic gneisses basement. High conductivity anomaly within the Kaladgi sediments represents a hydrothermal reservoir that is associated with faults/fractures beneath the Deccan Traps.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Bioavailability Assessment of the Novel Gsh-Functionalized Feb Nanoparticles Via Oxidative Stress and Trace Element Metabolism in Vitro: Promising Tools for Biomedical Applications
    (Springer, 2024) Aydemir, Duygu; Aribuga, Dilara; Hashemkhani, Mahshid; Acar, Havva Yagci; Çağıran, Özge Balcı; Ulusu, Nuriye Nuray
    Iron-based magnetic nanoparticles (NPs) have attracted significant attention in biomedical research, particularly for applications such as cancer detection and therapy, targeted drug delivery, magnetic resonance imaging (MRI), and hyperthermia. This study focuses on the synthesis and glutathione (GSH) functionalization of iron boride (FeB) nanoparticles (NPs) for prospective biomedical use. The GSH-functionalized FeB NPs (FeB@GSH) demonstrated ferromagnetic behavior, with a saturation magnetization (Ms) of 45.8 emu/g and low coercivity (Hc = 1000 Oe), indicating desirable magnetic properties for biomedical applications. Transmission electron microscopy (TEM) analysis of the FeB@GSH revealed well-dispersed nanoparticles with diameters smaller than 30 nm. Comprehensive nanotoxicity and biocompatibility assessments were performed using various healthy and cancer cell lines, including 293 T, HeLa, 3T3, MCF7, HCT116, and CFPAC-1. Cytotoxicity assays were conducted on FeB@GSH-treated cells over a dose range of 0-300 mu g/mL during 24-h incubations. Results indicated no significant differences in cell viability between treated and untreated control groups, confirming the biocompatibility of FeB@GSH. Further nanotoxicity evaluations were carried out on 3T3, 293 T, and CFPAC-1 cell lines, focusing on oxidative stress markers and cellular metabolism by measuring antioxidant enzyme activity. Additionally, ion release and mineral metabolism were assessed using inductively coupled plasma mass spectrometry (ICP-MS), revealing no notable variations between the treated and control groups. These findings suggest that FeB@GSH NPs exhibit excellent biocompatibility, making them promising candidates for diverse biomedical applications, including medical imaging, drug delivery systems, and therapeutic interventions.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 4
    A Facile Method for Boosting the Graphitic Carbon Nitride's Photocatalytic Activity Based on 0d/2d S-Scheme Heterojunction Nanocomposite Architecture
    (Elsevier, 2024) Kahraman, Zeynep; Kartal, Uğur; Gent, Aziz; Alp, Emre
    Graphitic carbon nitride (g-C 3 N 4 ) has received significant interest as a metal -free photocatalyst. The S -scheme photocatalytic system has great potential to improve the charge separation in semiconductor photocatalysts. In this study, we have fabricated non-toxic and low-cost photocatalytic nanocomposites of 0D/2D S -scheme heterojunction composed of iron oxide and graphitic carbon nitride by a facile method. The developed facile method provides a sustainable way with a high atom economy to further enhance the photocatalytic performance of exfoliated g-C 3 N 4 . The 0D -iron oxide/2D-C 3 N 4 exhibited nearly 10 times better than bulk g-C 3 N 4 and almost 60 % better than exfoliated g-C 3 N 4 under simulated solar light irradiation. The experimental results demonstrated that the effective charge -carrier mechanism led to an improved generation of reactive oxygen species (ROSs), resulting in an impressive photocatalytic performance. A serial photocatalytic test was also conducted to understand photocatalytic reaction mechanisms with various scavengers.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 2
    Electrocaloric Behaviour of Tape Cast and Grain Oriented Nbt-Kbt Ceramics
    (Elsevier Sci Ltd, 2024) Unal, Muhammet Ali; Karakaya, Merve; Irmak, Tugce; Yildirim-Ozarslan, Gokce; Avci, A. Murat; Fulanovic, Lovro; Adem, Umut
    We have investigated the effects of grain orientation and tape casting process on the electrocaloric properties of 0.82Na(0.5)Bi(0.5)TiO(3)-0.18 K0.5Bi0.5TiO3 (0.82NBT-0.18KBT) ceramics at the Morphotropic Phase Boundary (MPB), using direct and indirect measurements. We observe a larger electrocaloric response for the template-free ceramics compared to 7 and 10 wt% template containing ones, suggesting that grain orientation along rhombohedral < 100 > does not improve the electrocaloric response. Indirect measurements yielded a large adiabatic temperature change of around 3 K under an electric field of 50 kV/cm, which is significantly higher than 0.9 K reached at a lower electric field of 40 kV/cm using the direct measurement.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 10
    Impact of Simulated Inflammation and Food Breakdown on the Synergistic Interaction Between Corrosion and Wear on Titanium
    (Elsevier, 2024) Lima, A.R.; Pinto, A.M.P.; Toptan, F.; Alves, A.C.
    This paper investigates the impact of lactic acid and phosphoric acid additives in artificial saliva (AS), simulating inflammation and food breakdown, on the electrochemical and tribo-electrochemical behavior of titanium. The results showed that, unlike lactic acid, phosphoric acid significantly reduced corrosion resistance, mainly due to local damage and heterogeneities on the passive film. Non-additivated AS caused greater wear volume loss, with mechanical wear identified as the main mechanism. However, when additives were present, a synergistic interplay between corrosion and wear was observed. The study concludes that prolonged exposure to food breakdown could accelerate material degradation in titanium. © 2024 Elsevier Ltd
  • Article
    Citation - WoS: 3
    Citation - Scopus: 2
    Electrocaloric Behaviour of Tape Cast and Grain Oriented Nbt-Kbt Ceramics
    (Elsevier Sci Ltd, 2024) Unal, Muhammet Ali; Karakaya, Merve; Irmak, Tugce; Yildirim-Ozarslan, Gokce; Avci, A. Murat; Fulanovic, Lovro; Adem, Umut
    We have investigated the effects of grain orientation and tape casting process on the electrocaloric properties of 0.82Na(0.5)Bi(0.5)TiO(3)-0.18 K0.5Bi0.5TiO3 (0.82NBT-0.18KBT) ceramics at the Morphotropic Phase Boundary (MPB), using direct and indirect measurements. We observe a larger electrocaloric response for the template-free ceramics compared to 7 and 10 wt% template containing ones, suggesting that grain orientation along rhombohedral < 100 > does not improve the electrocaloric response. Indirect measurements yielded a large adiabatic temperature change of around 3 K under an electric field of 50 kV/cm, which is significantly higher than 0.9 K reached at a lower electric field of 40 kV/cm using the direct measurement.
  • Article
    Citation - Scopus: 3
    A Brief Overview on Geothermal Scaling
    (General Directorate of Mineral Research and Exploration (MTA), 2023) Isık, Tuğba; Baba, Alper; Chandrasekharam, Dornadula; Demir, Mustafa M.; Isık, Tuğba; Baba, Alper; Demir, Mustafa Muammer
    Hot spring waters are rich in terms of minerals. Since there are dramatic changes in thermodynamic parameters in geothermal power plants, such as a decrease in temperature and pressure, severe precipitation occurs throughout the system components in an uncontrolled manner. There are three main chemistries in deposits: carbonates (mainly calcium carbonates), silicates (metal silicates), and sulphides (antimony sulphide-stibnite). Energy harvesting is remarkably reduced out of the insulating nature of the deposit. Various actions need to be taken to mitigate this undesirable issue of scaling in geothermal systems. Geothermal systems are in fact quite complex, and the composition of brine and, accordingly, the chemistry of the deposit are not identical. Therefore, each system should be studied individually, and a tailor-made remedy should be developed. In this overview, the types of deposits in terms of chemistry and the actions (pH modification or antiscalant dosing) that should be taken to reduce scaling are mentioned, and potential chemistries of antiscalants are given.
  • Article
    Citation - WoS: 11
    Citation - Scopus: 13
    Magnesium-Ion Battery Anode From Polymer-Derived Sioc Nanobeads
    (Wiley, 2023) Guo, Wuqi; Kober, Delf; Gurlo, Aleksander; Bekheet, Maged F.; İçin, Öykü; Ahmetoğlu, Çekdar Vakıf
    Tin-containing silicon oxycarbide (SiOC/Sn) nanobeads are synthesized with different carbon/tin content and tested as electrodes for magnesium-ion batteries. The synthesized ceramics are characterized by thermogravimetric-mass spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, N2 sorption analysis, scanning electron microscope, energy-dispersive X-ray, and elemental analysis. Galvanostatic cycling tests, rate performance tests, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) tests, and ex situ XRD measurements are conducted. Results of battery performance tests present a high capacity of 198.2 mAh g-1 after the first discharging and a reversible capacity of 144.5 mAh g-1 after 100 cycles at 500 mA g-1. Excellent rate performance efficiency of 85.2% is achieved. Battery performances in this research are influenced by surface area, and tin contentof the SiOC/Sn nanobeads. EIS, CV tests, and ex situ XRD measurements reveal that higher surface area contributes to higher capacity by providing more accessible Mg2+ ion storage sites and higher rate capability by improving the diffusion process. Higher Sn content increases battery capacity through reversible Mg-Mg2Sn-Mg alloying/dealloying process and improves the rate performances by increasing electrical conductivity. Besides, SiOC advances cycling stability by preventing electrode collapse and enhances the capacity due to higher surface capacitive effects. SiOC nanobeads containing Sn nanoparticles are synthesized and tested as anode for magnesium-ion batteries. The anodes show high performance with reversible capacity of 144.5 mAh g-1 after 100 cycles at 500 mA g-1 and excellent rate performance efficiency of 85.2% from 50 to 500 mA g-1.image