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Article Citation - WoS: 102Citation - Scopus: 107Copper(0) Nanoparticles Supported on Silica-Coated Cobalt Ferrite Magnetic Particles: Cost Effective Catalyst in the Hydrolysis of Ammonia-Borane With an Exceptional Reusability Performance(Amer Chemical Soc, 2012) Kaya, Murat; Zahmakiran, Mehmet; Ozkar, Saim; Volkan, MurvetHerein we report the development of a new and cost-effective nanocomposite catalyst for the hydrolysis of ammonia-borane (NH3BH3), which is considered to be one of the most promising solid hydrogen carriers because of its high gravimetric hydrogen storage capacity (19.6% wt) and low molecular weight. The new catalyst system consisting of copper nanoparticles supported on magnetic SiO2/CoFe2O4 particles was reproducibly prepared by wet-impregnation of Cu(II) ions on SiO2/CoFe2O4 followed by in situ reduction of the Cu(II) ions on the surface of magnetic support during the hydrolysis of NH3BH3 and characterized by ICP-MS, XRD, XPS, TEM, HR-TEM and N-2 adsorption-desorption technique. Copper nanoparticles supported on silica coated cobalt(II) ferrite SiO2/CoFe2O4 (CuNPs@SCF) act as highly active catalyst in the hydrolysis of ammonia-borane, providing an initial turnover frequency of TOF = 2400 h(-1) at room temperature, which is not only higher than all the non-noble metal catalysts but also higher than the majority of the noble metal based homogeneous and heterogeneous catalysts employed in the same reaction.. More importantly, they were easily recovered by using a permanent magnet in the reactor wall and reused for up, to 10 recycles without losing their inherent catalytic activity significantly, which demonstrates the exceptional reusability of the CuNPs@SCF catalyst.Article Citation - WoS: 22Citation - Scopus: 23Complete Dehydrogenation of Hydrazine Borane on Manganese Oxide Nanorod-Supported Ni@ir Core-Shell Nanoparticles(Amer Chemical Soc, 2020) Yurderi, Mehmet; Top, Tuba; Bulut, Ahmet; Kanberoglu, Gulsah Saydan; Kaya, Murat; Zahmakiran, MehmetHydrazine borane (HB; N2H4BH3) has been considered to be one of the most promising solid chemical hydrogen storage materials owing to its high hydrogen capacity and stability under ambient conditions. Despite that, the high purity of hydrogen production from the complete dehydrogenation of HB stands as a major problem that needs to be solved for the convenient use of HB in on-demand hydrogen production systems. In this study, we describe the development of a new catalytic material comprised of bimetallic Ni@Ir core-shell nanoparticles (NPs) supported on OMS-2-type manganese oxide octahedral molecular sieve nanorods (Ni@Ir/OMS-2), which can reproducibly be prepared by following a synthesis protocol including (i) the oleylamine-mediated preparation of colloidal Ni@Ir NPs and (ii) wet impregnation of these ex situ synthesized Ni@Ir NPs onto the OMS-2 surface. The characterization of Ni@Ir/OMS-2 has been done by using various spectroscopic and visualization techniques, and their results have revealed the formation of well-dispersed Ni@Ir core-shell NPs on the surface of OMS-2. The catalytic employment of Ni@Ir/OMS-2 in the dehydrogenation of HB showed that Ni-0.22@Ir-0.78/OMS-2 exhibited high dehydrogenation selectivity (>99%) at complete conversion with a turnover frequency (TOF) value of 2590 h(-1) at 323 K, which is the highest activity value among all reported catalysts for the complete dehydrogenation of HB. Furthermore, the Ni-0.22@Ir-0.78/OMS-2 catalyst enables facile recovery and high stability against agglomeration and leaching, which make it a reusable catalyst in the complete dehydrogenation of HB. The studies reported herein also include the collection of wealthy kinetic data to determine the activation parameters for Ni-0.22@Ir-0.78/OMS-2-catalyzed dehydrogenation of HB.Article Citation - WoS: 3Citation - Scopus: 3Synthesis of Silver Nanoparticle-Immobilized Antibacterial Anion-Exchange Membranes for Salinity Gradient Energy Production by Reverse Electrodialysis(Amer Chemical Soc, 2024) Eti, Mine; Cihanoglu, Aydin; Hamaloglu, Kadriye Ozlem; Altiok, Esra; Guler, Enver; Tuncel, Ali; Kabay, NalanBiofouling, stemming from the attachment of living microorganisms, such as bacteria, which form resilient biofilms on membrane surfaces, presents a significant challenge that hampers the efficiency of anion-exchange membranes (AEMs) in reverse electrodialysis (RED) applications. This limitation curtails the generation of electrical power from salinity gradients, which notably is a sustainable form of energy known as osmotic energy. RED stands as a clean and promising process to harness this renewable energy source. This study aimed to impart antibacterial activity to synthesized AEMs by using silver nanoparticles (AgNPs). For that purpose, AgNPs were synthesized at 30 degree celsius using two different pH values (6.0 and 9.0) and immobilized into synthesized AEMs using the dip-coating technique. In nanoparticle synthesis, ascorbic acid and trisodium citrate were used as a reductant and a stabilizer, respectively, to take control of the particle size and agglomeration behavior. The results indicated that AgNPs synthesized at pH 6.0 were dispersed on the AEM surface without agglomeration. The stability of AgNPs immobilized on the membrane surface was tested under low- and high-saline solutions. The antibacterial activities of AEMs were determined with the colony-counting method using Gram-negative (Escherichia coli) bacterial suspension. The viability of bacteria dramatically decreased after the immobilization of AgNPs in the AEMs. In the short- and long-term RED tests, it has been observed that the AEMs having AgNPs have high energy-generating potentials, and power density up to 0.372 W/m(2) can be obtained.Conference Object Antibacterial Activity of Cubic Boron Nitride (cbn) Coatings on Stainless Steel Grade 316 (316l)(Amer Chemical Soc, 2010) Uzunoglu, Emel; Sengonul, Merih; Derici, Kursat; Biriken, Derya; Kaftanoglu, Bilgin; Sengonul, Merih[No Abstract Available]Article Citation - WoS: 47Citation - Scopus: 52Biocompatible Electroactive Tetra(aniline)-Conjugated Peptide Nanofibers for Neural Differentiation(Amer Chemical Soc, 2018) Arioz, Idil; Erol, Ozlem; Bakan, Gokhan; Dikecoglu, F. Begum; Topal, Ahmet E.; Urel, Mustafa; Guler, Mustafa O.Peripheral nerve injuries cause devastating problems for the quality of patients' lives, and regeneration following damage to the peripheral nervous system is limited depending on the degree of the damage. Use of nanobiomaterials can provide therapeutic approaches for the treatment of peripheral nerve injuries. Electroactive biomaterials, in particular, can provide a promising cure for the regeneration of nerve defects. Here, a supramolecular electroactive nanosystem with tetra(aniline) (TA)-containing peptide nanofibers was developed and utilized for nerve regeneration. Self-assembled TA conjugated peptide nanofibers demonstrated electroactive behavior. The electroactive self-assembled peptide nanofibers formed a well-defined three-dimensional nanofiber network mimicking the extracellular matrix of the neuronal cells. Neurite outgrowth was improved on the electroactive TA nanofiber gels. The neural differentiation of PC-12 cells was more advanced on electroactive peptide nanofiber gels, and these biomaterials are promising for further use in therapeutic neural regeneration applications.Article Citation - WoS: 1Citation - Scopus: 1On the Smco Dimer: a Detailed Density Functional Theory Analysis(Amer Chemical Soc, 2010) Oymak, Hueseyin; Erkoc, SakirMaking use of 21 different exchange-correlation functionals, we performed density functional theory calculations, within the effective core potential level, to investigate some spectroscopic and electronic features of the SmCo dimer in its ground state. A particular emphasis was placed on the (spin) multiplicity of SmCo. Most of the functionals under discussion unanimously agreed that the multiplicity of SmCo should be 10. It was observed that the nature of interaction between Sm and Co atoms to form the SmCo dirtier can be described, to a good approximation, by a Lennard-Jones curve. For the multiplicity value 10, the binding energy D, was seen to be in the range 1.08-1.77 eV, while the equilibrium separation distance and the fundamental frequency were found to be r(e) = 2.975 +/- 0.035 angstrom and omega(e) = 120 +/- 10 cm(-1), respectively.Article Citation - WoS: 15Metal-Salt Enhanced Grafting of Vinylpyridine and Vinylimidazole Monomer Combinations in Radiation Grafted Membranes for High-Temperature PEM Fuel Cells(Amer Chemical Soc, 2020) Mojarrad, Naeimeh Rajabalizadeh; Sadeghi, Sahl; Kaplan, Begum Yarar; Guler, Enver; Gursel, Selmiye AlkanProton exchange membranes were prepared and characterized for utilization in high-temperature proton exchange membrane fuel cells, HT-PEMFCs. 1-vinylimidazole (1-VIm) and 4-vinylpyridine (4VP) monomers were simultaneously grafted onto pre-irradiated ETFE (ethylene-co-tetrafluoroethylene) films which were prepared using gamma-rays with a dose of 100 kGy, as a robust substrate to prepare acid-base composite membranes. The grafting reaction was performed at 60 degrees C for 24 h followed by protonation via phosphoric acid doping in the subsequent step. The effect of adding ferrous salts as promoters in grafting was investigated by characterization of resultant membranes via thermal gravimetric analysis and mechanical tests. The fuel cell tests were conducted under different relative humidities (RHs) and applied temperatures. Membranes prepared with salt addition exhibited superior proton conductivities. Results including up to 80 mS cm(-1) conductivity at 110 degrees C in 60% RH and excellent thermal stability, even at 300 degrees C, suggest these membranes are promising for HT-PEMFC applications.Article Citation - WoS: 14Dissociative Adsorption of Water at (211) Stepped Metallic Surfaces by First-Principles Simulations(Amer Chemical Soc, 2017) Pekoz, Rengin; Donadio, DavideSteps at high-index metallic surfaces display higher chemical reactivity than close-packed surfaces and may give rise to selective adsorption and partial dissociation of water. Inspired by differential desorption experiments, we have studied the adsorption and dissociation of water clusters and one-dimensional wires on Pt(211) by density functional theory and molecular dynamics simulations. These calculations reveal that water at the step edges of Pt(211) adsorbs more weakly than at Pt(221), but partial dissociation of adsorbed water clusters is energetically competitive. We observe that the one-dimensional structure proposed experimentally can be realized only by partially dissociated water wires. In addition, weaker adsorption allows the formation of structures in which a number of water molecules detach from the step and form weak hydrogen bonds with the terrace. This study is further extended to the energetics of small water clusters on (211) surfaces of Ir, Rh, and Pd.Article Citation - WoS: 80Citation - Scopus: 86New Approach for the Surface Enhanced Resonance Raman Scattering (serrs) Detection of Dopamine at Picomolar (pm) Levels in the Presence of Ascorbic Acid(Amer Chemical Soc, 2012) Kayat, Murat; Volkan, MurvetThe development of a novel surface-enhanced resonance Raman scattering (SERRS) platform that allows fast and sensitive detection of dopamine (DA) has been reported. The iron-nitrilotriacetic acid attached silver nanoparticle (Ag-Fe(NTA)) substrate provides remarkable sensitivity and reliable repeatability. The advantages of both the surface functionalization for specific analytes and the SERRS are integrated into a single functional unit. While the silver core gives the necessary enhancing properties, the Fe-NTA receptors can trap DA adjacent the silver core and the NTA-Fe-DA complex formed provides resonance enhancement with a 632.8 nm laser. DA could be detected in pM level without any pretreatment with a reliable discrimination against AA, by utilizing low laser power (10 mW) and short data acquisition time (10 s). The high sensitivity along with the improved selectivity of this sensing approach is a significant step toward molecular diagnosis of Parkinson's disease.Article Citation - WoS: 14Citation - Scopus: 8Structural and Optical Properties of Interfacial Inse Thin Film(Amer Chemical Soc, 2024) Emir, Cansu; Tataroglu, Adem; Coskun, Emre; Ocak, Sema BilgeThis study presents a comprehensive investigation of the optical and structural characteristics of the indium selenide (InSe) film prepared on a glass substrate. The structural characteristics of the InSe film were analyzed using characterization techniques including X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy while the UV-vis spectrophotometry method was used in the spectral range between 500 and 1000 nm to examine the optical characteristics. Thus, the UV-vis spectroscopic data were used to extract several optical parameters including extinction coefficient (k), optical band gap (E-g), refractive index (n), absorption coefficient (alpha), and optical conductivity (sigma(opt)). The optical transition of InSe was found as a direct transition. However, the optical analysis of this study has revealed that the InSe film has the potential to be used in various optoelectronic and photovoltaic applications.
