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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.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: 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: 25Citation - Scopus: 28Semi-Ipn Chitosan/Peg Microspheres and Films for Biomedical Applications: Characterization and Sustained Release Optimization(Amer Chemical Soc, 2012) Gunbas, Ismail Dogan; Sezer, Umran Aydemir; Iz, Sultan Gulce; Gurhan, Ismet Deliloglu; Hasirci, NesrinMicro drug carriers are one of the efficient methods for local or systemic cancer treatment. In this study, the aim was to prepare a novel semi-interpenetrated (semi-IPN) micro system by using biocompatible chitosan (CH) and polyethylene glycol (PEG). Various combinations of the systems were prepared and loaded with a model chemotherapeutic drug, methotrexate (MTX), and the effects of composition on the properties and the release behavior of microspheres were examined. Also, the mechanical and thermal properties were examined on film forms of similar compositions. Increase in cross-linking caused a decrease in particle size of CH from 144 to 91 mu m, while the addition of PEG caused an increase up to 163 mu m. Elastic modulus values of the films first increased and then decreased parallel to PEG content. In vitro studies showed faster MTX release from semi-IPN CH-PEG microspheres as compared to pure CH ones. Promising results were obtained in the development of biodegradable drug vehicles.Article Citation - WoS: 1Citation - Scopus: 1Penta-Graphene/SnS2 Heterostructures with Z-Scheme Charge Transfer for Efficient Photocatalytic Water Splitting(Amer Chemical Soc, 2025) Nasoz, Duygu Lale; Surucu, Ozge; Wang, Xiaotian; Surucu, Gokhan; Sarac, Yasemin; Gencer, AysenurThe present study explores the photocatalytic potential of penta-graphene (PG) and SnS2 monolayers, along with their heterostructures (PG/SnS2), using Density Functional Theory (DFT). Structural analysis confirms that the PG/SnS2 heterostructure exhibits enhanced stability, efficient charge separation, and suitable band alignment. Optimized lattice parameters (3.66 & Aring; for PG and 3.88 & Aring; for SnS2) closely matched literature values, while ab initio molecular dynamics (AIMD) confirmed thermodynamic stability at 300 K. The heterostructure's band gap of 2.75 eV (HSE method) supports visible light absorption, and the band edge positions enable hydrogen and oxygen evolution reactions across pH 0 to 6. Optical analysis reveals significant visible-light absorption with an optical band gap of 1.43 eV. Additionally, this study identifies a Z-scheme charge transfer mechanism in the PG/SnS2 heterostructure, facilitated by an internal built-in electric field that drives directional charge migration, effectively enhancing electron-hole separation and suppressing recombination losses. This Z-scheme mechanism optimizes redox reactions, making PG/SnS2 a highly efficient photocatalyst for solar-driven hydrogen production. Furthermore, the effect of water solvent is investigated, and it reveals that this heterostructure is stable under water solvent, having suitable band edges for the photocatalytic water splitting. These findings highlight the PG/SnS2 heterostructure as a promising candidate for sustainable hydrogen generation, offering a new perspective for the design of next-generation 2D photocatalytic materials.Article Citation - WoS: 4Citation - Scopus: 3Exploring the Thermal Stability of Sb2se3 for Potential Applications Through Advanced Thermal Analysis Methods(Amer Chemical Soc, 2025) Altuntas, Gozde; Isik, Mehmet; Surucu, Gokhan; Parlak, Mehmet; Surucu, OzgeAntimony selenide (Sb2Se3) is a promising material for energy applications, including photovoltaics, thermoelectrics, and photodetectors, due to its favorable electronic properties, availability, and low toxicity. However, its thermal stability, crucial for device efficiency and reliability, has been less explored, leaving a gap in understanding its high-temperature suitability. This study evaluates the thermal stability of Sb2Se3 using thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The results show that Sb2Se3 remains stable up to 500 degrees C, with two significant weight loss stages: 1.75% between 500 and 610 degrees C, and 3.50% between 610 and 775 degrees C, indicating decomposition processes. Activation energies for the decomposition phases were determined as 121.8 and 57.2 kJ/mol using the Coats-Redfern method. Additionally, an endothermic phase transition was observed between 599 and 630.6 degrees C via DSC analysis. These findings demonstrate Sb2Se3's potential for high-temperature energy applications, providing essential insights for optimizing its use in solar cells, thermoelectric devices, and other technologies.Article Citation - WoS: 19Citation - Scopus: 18Deviations From Born-Oppenheimer Theory in Structural Chemistry: Jahn-Teller, Pseudo Jahn-Teller, and Hidden Pseudo Jahn-Teller Effects in C3h3< and C3h3<(Amer Chemical Soc, 2013) Kayi, H.; Garcia-Fernandez, P.; Bersuker, I. B.; Boggs, J. E.The electronic structure and vibronic coupling in two similar molecular systems, radical C3H3 and anion C3H3-, in ground and excited states, are investigated in detail to show how their equilibrium structures, in deviation from the Born-Oppenheimer approximation, originate from the vibronic mixing of at least two electronic states, producing the Jahn-Teller UT), pseudo JT (PJT), and hidden PJT effects. Starting with the high-symmetry geometry D3h of C3H3, we evaluated its 2-fold degenerate ground electronic state 2E" and two lowest excited states 2A,' and 2E' and found that all of them contribute to the distortion of the ground state via the JT vibronic coupling problem E" e' and two PJT problems (E" + A(1)') circle star e" and (E" + E') circle times (a2" + e"); all the three active normal modes e'(1335 e"(1030 cm(-1)), and a2"(778 cm(-1)) are imaginary, meaning that all the three vibronic couplings are sufficiently strong to cause instability, albeit in different directions. The first of them, the ground state JT effect, enhances one of the C-C bonds (toward an ethylenic form with C-2v symmetry), while the two PJT effects produce, respectively, cis (a(2)" toward C-3v symmetry) and trans (e") puckering of the hydrogen atoms. As a result, C3H3 has two coexisting equilibrium configurations with different geometry. In the C3H3- anion, the ground electronic state in DA symmetry is an orbitally nondegenerate spin triplet (3)A(2)' with a group of close in energy singlet and triplet excited states in the order of (1)A(1),', (3)A(1)', E-1", E-3", and E-1'. This shows that two PJT couplings, (3A(2)' + (3)A(1)") circle times a(2)" and (3A2' + 3E") e", may influence the geometry of the equilibrium structure in the 3A2' state. Indeed, both vibrational modes, a(2)"(1034 cm(-1)) and e"(1284 cm(-1)), are imaginary in this state. Similar to the radical case, they produce, respectively, cis (a(2)") and trans (e") puckering of the hydrogen atoms, but no e' distortion of the basic C-3 triangle; the equilibrium configuration with Cs symmetry occurs along the stronger e" distortions. Another higher-in-energy triplet-state minimum with C-2v symmetry emerges as a result of a strong JTE in the excited 3E" electronic state. In addition to these APES minima with spin-triplet electronic states, the system has a coexisting minimum with a spin-singlet electronic state, which is shown to be due to the hidden PJT effect that couples two singlet excited states. The two lowest equilibrium configurations of the C3H3- anion with different geometry and spin realize a (common to all electronic e(2) configurations) magnetic and structural bistability accompanied by a spin crossover. Some general spectroscopic consequences are also noted. As a whole, this article is intended to demonstrate the efficiency of the vibronic coupling approach in rationalizing the origin of complicated structural features of molecular systems as due to a combination of nonadiabatic JT effects.
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