Browsing by Author "Duran, Hatice"
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Item Embargo Continuous conducting architecture developed by supporting Prussian blue analogue on metal-organic framework derived carbon-doped manganese- oxide nanorods for high-performance sodium-ion batteries(Elsevier BV, 2023-07-03) Ullah, Irfan; Saeed, Roheen; Inayat, Abid; Zubair, Muhammad; Wu, Xianyong; Duran, Hatice; Haider, Ali; Pope, Michael A.; Hussain, IrshadPrussian blue analogues (PBA) are regarded as promising cathode materials for sodium-ion batteries (SIBs) owing to their open framework with large interstitial sites to accommodate Na+ ions. However, PBA suffer from low electronic conductivity and mechanical instability, which may be improved by their structural modification leading to enhanced kinetics. In this regard, we report an in-situ integration of ultra-small PBA cubes into three-dimensional metal organic framework (MOF) derived carbon-doped manganese oxide nanorods (C-Mn2O3), which form a continuous conductive architecture with intimate PBA/C-Mn2O3 contact. The C-Mn2O3 nanorods provide nucleation sites for the growth of PBA cubes and further act as the electronic pathway to improve electrode reaction kinetics. This hierarchical configuration effectively buffers the lattice expansion, which improve the structural stability of NiCoPBA. Consequently, the composite exhibits promising performance in aqueous Na+ batteries. Specifically, it delivers a high capacity of 97 mAh/g within a narrow potential window of and retained 82% capacity for 1000 cycles in aqueous electrolyte. It shows even higher capacity of 136 mAh/g and similar capacity retention (76% after 1000 cycles) in non-aqueous electrolytes. The promising performance of developed materials demonstrates the significant impact decreasing the size of PBA cubes has on the capacity by reducing the diffusion pathways and thus facilitating intercalation/deintercalation within the cubes. This study offers new insights of exploiting redox-active substrates to modify and stabilize PBA materials for energy storage applications.Item Open Access Fabrication of NiCu interconnected porous nanostructures for highly selective methanol oxidation coupled with hydrogen evolution reaction(Elsevier, 2022-01-15) Arshad, F.; Tahir, A.; Haq, T.; Duran, Hatice; Hussain, I.; Sher, F.Electrocatalytic water electrolysis is the most promising clean and efficient process for pure and clean generation of hydrogen. However, water oxidation reaction requires a large overpotential owing to its slow kinetics, causing a lower efficiency of hydrogen production and high energy consumption. Herein, we report the bimetallic NiCu interconnected porous nanostructures on copper foil (NiCu@Cu) prepared by hydrogen bubbles templating electrodeposition technique for methanol oxidation reaction (MOR), which replaces the kinetically sluggish water oxidation reaction and enhances the hydrogen production with lower energy input. With their high macroporosity, interconnected growth on copper foil with excellent conductivity and easy flow of electrolyte on electrode interface, and stabilization of active sites due to bimetallic synergistic effects, the NiCu@Cu electrocatalysts exhibit outstanding activities for HER and MOR. The NiCu@Cu requiring just 1.32 V anodic potential vs RHE at 10 mA cm−2 for MOR which is significantly lower than that for water oxidation reaction. Moreover, the electrolyzer using NiCu@Cu/NiCu@Cu for anodic MOR and cathodic H2 production only needs a low input voltage of 1.45 V to deliver a current density of 10 mA cm−2 with impressive durability.Item Embargo Histopathology of chironomids exposed to fly ash and microplastics as a new biomarker of ecotoxicological assessment(Elsevier BV, 2023-12-10) Stojanović, J.; Savić-Zdravković, D.; Jovanović, B.; Vitorović, J.; Bašić, J.; Stojanović, I.; Žabar Popović, A.; Duran, Hatice; Kračun Kolarević, M.; Milošević, Đ.Histopathology of chironomids exposed to fly ash and microplastics as a new biomarker of ecotoxicological assessment In the last few decades, industrial pollution has gained extensive attention in terms of its effect on the aquatic environment. This imposes the need to develop sensitive biomarkers for early detection of pollutant toxicity in ecotoxicological assessment. The advantages of histopathological biomarkers are many, including quick reaction to the presence of contaminants, and the small number of individuals needed for efficient analysis. The present study analyzed the negative effect of lignite coal fly ash (LCFA) and microplastic particles (MPs) on Chironomus riparius, a suggested model organism by the Organization for Economic Cooperation and Development (OECD). This study aimed to perform histological analyses of larval tissues and target potential changes in treated groups that could serve as promising histopathological biomarkers of the contaminant's negative effects. Following that, other known sensitive sub-organismal biomarkers were analyzed and paired with the histopathological ones. Histological analysis of larvae showed a significantly decreased length of microvilli in midgut regions II and III in both treatments. Treatments with MPs affected oxidative stress parameters: thiobarbituric acid reactive substances (TBARS), advanced oxidation protein products (AOPP), superoxide dismutase (SOD), and hemoglobin levels, while LCFA significantly affected all tested sub-organismal biomarkers (DNA damage, levels of AOPP, SOD, and hemoglobin), except catalase (CAT) and TBARS. When observing histological slides, a significant shortage of brush border length in the posterior parts of the midgut was detected in all treatments. In the case of LCFA, the appearance of intensive vacuolization of digestive cells with inclusions resembling apoptotic bodies, in mentioned regions was also detected. This study demonstrated high sensitivity of brush border length to the MPs and LCFA exposure, complementary to other tested sub-organismal biomarkers. Revealing the great potential of this histopathological biomarker in ecotoxicological studies contributes to the international standard ecotoxicology assessment of emerging pollutants.Item Open Access Melting temperature depression and phase transitions of nitrate-based molten salts in nanoconfinement(American Chemical Society, 2022-07-11) Yazlak, M. G.; Khan, Q. A.; Steinhart, M.; Duran, HaticeHybrids of nitrate-based molten salts (KNO3, NaNO3, and Solar Salt) and anodic aluminum oxide (AAO) with various pore sizes (between 25 and 380 nm) were designed for concentrated solar power (CSP) plants to achieve low melting point ([removed]1 W m-1K-1). AAO pore surfaces were passivated with octadecyl phosphonic acid (ODPA), and the results were compared with as-anodized AAO. The change in phase transition temperatures and melting temperatures of salts was investigated as a function of pore diameter. Melting temperatures decreased for all salts inside AAO with different pore sizes while the highest melting temperature decrease (ΔT = 173 ± 2 °C) was observed for KNO3filled in AAO with a pore diameter of 380 nm. Another nanoconfinement effect was observed in the crystal phases of the salts. The ferroelectric phase of KNO3(γ-phase) formed at room temperature for KNO3/AAO hybrids with pore size larger than 35 nm. Thermal conductivity values of molten salt (MS)/AAO hybrids were obtained by thermal property analysis (TPS) at room temperature and above melting temperatures of the salts. The highest increase in thermal conductivity was observed as 73% for KNO3/AAO-35 nm. For NaNO3/AAO-380 nm hybrids, the thermal conductivity coefficient was 1.224 ± 0.019 at room temperature. To determine the capacity and efficiency of MS/AAO hybrids during the heat transfer process, the energy storage density per unit volume (J m-3) was calculated. The highest energy storage capacity was calculated as 2390 MJ m-3for KNO3/AAO with a pore diameter of 400 nm. This value is approximately five times higher than that of bulk salt.Item Open Access The role of intermetallic particles on mode I crack propagation mechanisms in metal plates(Elsevier Ltd, 2021-08) Tekoğlu, C.; Çelik, Ş.; Duran, Hatice; Bair-Stegmaier, S.; Nielsen, K. L.In metal plates, the crack propagation mechanism sets the amount of the plastic deformation before failure: a slanted or a cup–cone crack typically yields limited plate thinning within the fracture process zone, while large deformation precedes cup–cup crack propagation. The present work investigates the effect of intermetallic particles on the propagation mechanisms and the associated fracture surface morphologies when tearing Al 1050 plates under far-field mode I loading. Both single edge notched and double edge notched tension specimens, with thicknesses ranging from 0.5 to 5 mm, were tested. The chemical compositions of intermetallic particles were determined by performing energy dispersive X-ray measurements, and their morphological features were characterized by Scanning Electron Microscopy (SEM). Likewise, SEM images were taken to display the fracture surfaces, and the details of the surface morphology were visualized in three dimensions by using X-ray Tomography scanning. The experimental results indicate that an increase in the volume fraction, size, and aspect ratio of the intermetallic particles all promote slanted/cup–cone cracks, while a low amount of small, circular particles leads to cup–cup cracks. Furthermore, two-dimensional finite element simulations for mode I crack propagation support the experimental findings.Item Open Access Ultraviolet-printing-assisted surface-confined growth of silver nanoparticles on flexible polymer films for Cu2+ and H2S sensing(American Chemical Society, 2021-08-27) Ashfaq, B.; Azeem, I.; Sohail, M.; Yüce, F. G.; Çitoǧlu, S.; Nayab, S.; Abdullah, M.; Duran, Hatice; Yameen, B.Metal nanoparticles (NPs) confined on the surface of flexible polymers films are highly sought after for a diverse range of applications. Herein, we report a facile substrate-independent strategy for surface-confined growth of silver NPs (AgNPs) on the surfaces of chemically diverse flexible polymer film substrates represented by polypropylene (PP), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). The surfaces of polymer films were subjected to ultraviolet-printing and conjugated to the hyperbranched polyethyleneimine (PEI). The PEI-functionalized surfaces were subjected to surface-confined growth of AgNPs via three approaches. Besides PEI, the ability of quaternary amine and carboxylic acid functional groups to assist surface-confined growth of AgNPs is also evaluated. All the films with surface-confined AgNPs exhibited absorbance due to the surface plasmon resonance (SPR) characteristic of AgNPs. The AgNPs confined on the surface of PP films were functionalized with 4-mercaptobenzoic acid, and the λmax for SPR absorbance of the resulting platform was found to exhibit a markedly higher bathochromic shift when exposed to Cu2+ ions. This Cu2+ ions sensor could sense Cu2+ ions with a limit of detection of 2.6 ppm. Besides Cu2+ sensing via a bathochromic shift in λmax for SPR absorbance, the SPR absorbance of AgNPs confined on the surface of PP films was found to diminish upon exposure to the aqueous solution of sodium hydrosulfide (NaSH), which acts as a hydrogen sulfide (H2S) donor. The intensity of the SPR absorbance was found to decrease >40% upon exposure to 5 μM aqueous NaSH solution, whereas the SPR signal almost completely disappeared with visual decoloration when the films were exposed to 50 μM aqueous NaSH solution. This highlights the H2S sensing ability of the AgNPs confined on the surface of PP films. In brief, this study is a step toward the future development of flexible chemical sensor platforms and beyond.