Browsing by Author "Zahmakiran, Mehmet"

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Ald Preparation of Sio2 Protected Pd-Mnox Nanoparticles Supported on Tio2: Highly Efficient Nanocatalyst for the Dehydrogenation of Formic Acid
(Amer Chemical Soc, 2017) Caner, Nurdan; Yurderi, Mehmet; Bulut, Ahmet; Zahmakiran, Mehmet
Amine Grafted Silica Supported Craupd Alloy Nanoparticles: Superb Heterogeneous Catalysts for the Room Temperature Dehydrogenation of Formic Acid
(Royal Soc Chemistry, 2015) Yurderi, Mehmet; Bulut, Ahmet; Caner, Nurdan; Celebi, Metin; Kaya, Murat; Zahmakiran, Mehmet
Herein we show that a previously unappreciated combination of CrAuPd alloy nanoparticles and amine-grafted silica support facilitates the liberation of CO-free H-2 from dehydrogenation of formic acid with record activity in the absence of any additives at room temperature. Furthermore, their excellent catalytic stability makes them isolable and reusable heterogeneous catalysts in the formic acid dehydrogenation.
Amine-Functionalized Graphene Nanosheet-Supported Pdauni Alloy Nanoparticles: Efficient Nanocatalyst for Formic Acid Dehydrogenation
(Royal Soc Chemistry, 2018) Bulut, Ahmet; Yurderi, Mehmet; Kaya, Murat; Aydemir, Murat; Baysal, Akin; Durap, Feyyaz; Zahmakiran, Mehmet
Formic acid (HCOOH), a major by-product of biomass processing with high energy density, stability and non-toxicity, has a great potential as a safe and a convenient liquid hydrogen (H-2) storage material for combustion engines and fuel cell applications. However, high-purity hydrogen release from the catalytic decomposition of aqueous formic acid solution at desirable rates under mild conditions stands as a major challenge that needs to be solved for the practical use of formic acid in on-demand hydrogen generation systems. Described herein is a new nanocatalyst system comprised of 3-aminopropyltriethoxysilane-functionalized graphene nanosheet-supported PdAuNi alloy nanoparticles (PdAuNi/f-GNS), which can reproducibly be prepared by following double solvent method combined with liquid-phase chemical reduction, all at room temperature. PdAuNi/f-GNS selectively catalyzes the decomposition of aqueous formic acid through the dehydrogenation pathway (similar to 100% H-2 selectivity), in the absence of any promoting additives (alkali formates, Bronsted bases, Lewis bases, etc.). PdAuNi/f-GNS nanocatalyst provides CO-free H-2 generation with a turnover frequency of 1090 mol H-2 mol metal(-1) h(-1) in the additive-free dehydrogenation of formic acid at almost complete conversion (>= 92%) even at room temperature. The catalytic activity provided by PdAuNi/f-GNS nanocatalyst is higher than those obtained with the heterogeneous catalysts reported to date for the additive-free dehydrogenation of formic acid. Moreover, PdAuNi/f-GNS nanoparticles show high durability against sintering, clumping and leaching throughout the catalytic runs, so that the PdAuNi/f-GNS nanocatalyst retains almost its inherent catalytic activity and selectivity at the end of the 10th recycle.
Amylamine Stabilized Platinum(0) Nanoparticles: Active and Reusable Nanocatalyst in the Room Temperature Dehydrogenation of Dimethylamine-Borane
(Royal Soc Chemistry, 2014) Sen, Fatih; Karatas, Yasar; Gulcan, Mehmet; Zahmakiran, Mehmet
Herein, we report the preparation and characterization of platinum(0) nanoparticles stabilized by amylamine (C5H11NH2) ligands plus their catalytic use in the room temperature dehydrocoupling of dimethylamine-borane ((CH3)(2)NHBH3), which has attracted recent attention as a promising solid hydrogen storage material. Amylamine stabilized platinum(0) nanoparticles were reproducibly generated by an ethanol-superhydride reduction method and their preliminary characterization was done by ICP-OES, XRD, ATR-IR, TEM, HRTEM, and XPS spectroscopies. The sum of their results shows the formation of highly crystalline and colloidally stable platinum(0) nanoparticles. The catalytic performance of these new platinum(0) nanoparticles in terms of activity, isolability and reusability was investigated in the catalytic dehydrocoupling of dimethylamine-borane, in which they were found to be active and reusable heterogeneous catalysts even at room temperature.
Atomic Layer Deposition of Ruthenium Nanoparticles on Electrospun Carbon Nanofibers: a Highly Efficient Nanocatalyst for the Hydrolytic Dehydrogenation of Methylamine Borane
(Amer Chemical Soc, 2018) Khalily, Mohammad Aref; Yurderi, Mehmet; Haider, Ali; Bulut, Ahmet; Patil, Bhushan; Zahmakiran, Mehmet; Uyar, Tamer
We report the fabrication of a novel and highly active nanocatalyst system comprising electrospun carbon nanofiber (CNF)-supported ruthenium nanoparticles (NPs) (Ru@CNF), which can reproducibly be prepared by the ozone-assisted atomic layer deposition (ALD) of Ru NPs on electrospun CNFs. Polyacrylonitrile (PAN) was electropsun into bead-free one-dimensional (1D) nanofibers by electrospinning. The electrospun PAN nanofibers were converted into well-defined 1D CNFs by a two-step carbonization process. We took advantage of an ozone-assisted ALD technique to uniformly decorate the CNF support by highly monodisperse Ru NPs of 3.4 +/- 0.4 nm size. The Ru@CNF nanocatalyst system catalyzes the hydrolytic dehydrogenation of methylamine borane (CH3NH2BH3), which has been considered as one of the attractive materials for the efficient chemical hydrogen storage, with a record turnover frequency of 563 mol H-2/mol Ru x min and an excellent conversion (>99%) under air at room temperature with the activation energy (E-a) of 30.1 kJ/mol. Moreover, Ru@CNF demonstrated remarkable reusability performance and conserved 72% of its inherent catalytic activity even at the fifth recycle.
Atomic Layer Deposition-Sio2 Layers Protected Pdconi Nanoparticles Supported on Tio2 Nanopowders: Exceptionally Stable Nanocatalyst for the Dehydrogenation of Formic Acid
(Elsevier Science Bv, 2017) Caner, Nurdan; Bulut, Ahmet; Yurderi, Mehmet; Ertas, Ilknur Efecan; Kivrak, Hilal; Kaya, Murat; Zahmakiran, Mehmet
TiO2 nanopowders supported trimetallic PdCoNi alloy nanoparticles were simply and reproducibly prepared by wet-impregnation followed by simultaneous reduction method, then to enhance their stability against to sintering and leaching atomic layer deposition (ALD) technique was utilized to grow SiO2 layers amongst these surface bound PdCoNi alloy nanoparticles (PdCoNi/TiO2-ALD-SiO2). These new nanomaterials are characterized by the combination of complimentary techniques and sum of their results exhibited that the formation of ALD-SiO2 layers protected well-dispersed and highly crystalline PdCoNi alloy nanoparticles (ca. 3.52 nm) supported on TiO2 nanopowders. The catalytic performance of the resulting PdCoNi/TiO2-ALD-SiO2 in terms of activity, selectivity and stability was investigated in the dehydrogenation of aqueous formic acid (HCOOH), which has recently been suggested as a promising hydrogen storage material with a 4.4 wt% hydrogen capacity, solution under mild conditions. The results collected from our systematic studies revealed that PdCoNi/TiO2-ALD-SiO2 nanomaterial can act as highly active and selective nanocatalyst in the formic acid dehydrogenation at room temperature by providing an initial turnover frequency (TOF) value of 207 mol H-2/mol metal;: h and >99% of dehydrogenation selectivity at almost complete conversion. More importantly, the catalytic reusability experiments separately carried out with PdCoNi/TiO2-ALD-SiO2 and PdCoNi/TiO2 nanocatalysts in the dehydrogenation of formic acid under more forcing conditions pointed out that PdCoNi/TiO2-ALD-SiO2 nanocatalyst displays unprecedented catalytic stability against to leaching and sintering throughout the reusability experiments it retains almost its inherent activity, selectivity and conversion even at 20th reuse, whereas analogous PdCoNi/TiO2 completely lost its catalytic performance. (C) 2017 Elsevier B.V. All rights reserved.
Carbon Dispersed Copper-Cobalt Alloy Nanoparticles: a Cost-Effective Heterogeneous Catalyst With Exceptional Performance in the Hydrolytic Dehydrogenation of Ammonia-Borane
(Elsevier, 2016) Bulut, Ahmet; Yurderi, Mehmet; Ertas, Ilknur Efecan; Celebi, Metin; Kaya, Murat; Zahmakiran, Mehmet
Herein, we report the development of a new and cost-effective nanocatalyst for the hydrolytic dehydrogenation of ammonia-borane (NH3BH3), which is considered to be one of the most promising solid hydrogen carriers due to its high gravimetric hydrogen storage capacity (19.6 wt%) and low molecular weight. The new catalyst system consisting of bimetallic copper-cobalt alloy nanoparticles supported on activated carbon was simply and reproducibly prepared by surfactant-free deposition-reduction technique at room temperature. The characterization of this new catalytic material was done by the combination of multi-pronged techniques including ICP-MS, XRD, XPS, BFTEM, HR-TEM, STEM and HAADF-STEM-line analysis. The sum of their results revealed that the formation of copper-cobalt alloy nanoparticles (d(mean) =1.8 nm) on the surface of activated carbon (CuCo/C). These new carbon supported copper-cobalt alloy nanoparticles act as highly active catalyst in the hydrolytic dehydrogenation of ammonia-borane, providing an initial turnover frequency of TOF = 2700 h(-1) at 298 K, 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, easy recovery and high durability of these supported CuCo nanoparticles make CuCo/C recyclable heterogeneous catalyst for the hydrolytic dehydrogenation of ammonia-borane. They retain almost their inherent activity even at 10th catalytic reuse in the hydrolytic dehydrogenation of ammonia-borane at 298K. (C) 2015 Elsevier B.V. All rights reserved.
Carbon Supported Trimetallic Pdniag Nanoparticles as Highly Active, Selective and Reusable Catalyst in the Formic Acid Decomposition
(Elsevier Science Bv, 2014) Yurderi, Mehmet; Bulut, Ahmet; Zahmakiran, Mehmet; Kaya, Murat
Trimetallic PdNiAg nanoparticles supported on activated carbon were simply and reproducibly prepared by wet-impregnation followed by simultaneous reduction method without using any stabilizer at room temperature. The characterization of the resulting material was done by the combination of complimentary techniques and the sum of their results shows that the formation of well-dispersed 5.6 +/- 2.2 nm PdNiAg nanoparticles in alloy form on the surface of activated carbon. These carbon supported PdNiAg nanoparticles were employed as heterogeneous catalyst in the catalytic decomposition of formic acid, which has great potential as a safe and convenient hydrogen carrier for fuel cells, under mild conditions. It was found that PdNiAg/C can catalyze the dehydrogenation of formic acid with high selectivity (similar to 100%) and activity (TOF = 85 h(-1)) at 50 degrees C. More importantly, the exceptional stability of PdNiAg nanoparticles against to agglomeration, leaching and CO poisoning make PdNiAg/C reusable catalyst in the formic acid dehydrogenation. PdNiAg/C catalyst retains almost its inherent activity (>94%) even at 5th reuse in the dehydrogenation of formic acid with high selectivity (similar to 100%) at complete conversion. The work reported here also includes the compilation of kinetic data for PdNiAg/C catalyzed dehydrogenation of formic acid depending on catalyst [PdNiAg], substrate [HCOOH], promoter [HCOONa] concentrations and temperature to determine the rate expression and the activation parameters (Ea, Delta H-#, and Delta S-#) of the catalytic reaction. (C) 2014 Elsevier B.V. All rights reserved.
Catalytic Methanolysis of Hydrazine Borane: a New and Efficient Hydrogen Generation System Under Mild Conditions
(Royal Soc Chemistry, 2012) Karahan, Senem; Zahmakiran, Mehmet; Ozkar, Saim
Safe and efficient hydrogen storage is a major obstacle for using hydrogen as an energy carrier. Therefore, intensive efforts have been focused on the development of new materials for chemical hydrogen storage. Of particular importance, hydrazine borane (N2H4BH3) is emerging as one of the most promising solid hydrogen carriers due to its high gravimetric hydrogen storage capacity (15.4 wt%) and low molecular weight. Herein, we report metal catalyzed methanolysis of hydrazine borane (N2H4BH3, HB) as a fast hydrogen generation system under mild conditions. When trace amounts of nickel(II) chloride (NiCl2) is added to the methanol solution of hydrazine borane ([HB]/[Ni] >= 200) the reaction solution releases 3 equiv. of H-2 with a rate of 24 mol H-2 (mol Ni min)(-1) at room temperature. The results reported here also includes (i) identification of the reaction products by using ATR-IR, DP-MS, H-1 and B-11 NMR spectroscopic techniques and the establishment of the reaction stoichiometry, (ii) investigation of the effect of substrate and catalyst concentrations on the hydrogen generation rate to determine the rate law for the catalytic methanolysis of hydrazine borane, (iii) determination of the activation parameters (E-a, Delta H-#, and Delta S-#) for the catalytic methanolysis of hydrazine borane by using the temperature dependent rate data of the hydrogen generation.
Chromium Based Metal-Organic Framework Mil-101 Decorated Palladium Nanoparticles for the Methanolysis of Ammonia-Borane
(Royal Soc Chemistry, 2020) Caner, Nurdan; Yurderi, Mehmet; Bulut, Ahmet; Kanberoglu, Gulsah Saydan; Kaya, Murat; Zahmakiran, Mehmet
Palladium nanoparticles stabilized by an MIL-101 metal-organic framework (Pd@MIL-101) are synthesized by a novel synthesis approach. A Pd@MIL-101 catalyst facilitates H(2)generation from the methanolysis of ammonia-borane with record catalytic activity (TOF = 1080 min(-1)) at room temperature. Moreover, the exceptional stability of Pd@MIL-101 makes it a reusable heterogeneous catalyst in this catalytic transformation.
Cobalt Nanoparticles Supported on Alumina Nanofibers (co/Al2o3): Cost Effective Catalytic System for the Hydrolysis of Methylamine Borane
(Pergamon-elsevier Science Ltd, 2019) Baguc, Ismail Burak; Yurderi, Mehmet; Bulut, Ahmet; Celebi, Metin; Kanberoglu, Gulsah Saydan; Zahmakiran, Mehmet; Baysal, Akin
Amongst different amine-borane derivatives, methylamine-borane (CH3NH2BH3) seems to be one of the capable aspirants in the storing of hydrogen attributable to its high hydrogen capacity, stability and aptitude to generate hydrogen through its catalytic hydrolysis reaction under ambient conditions. In this research paper, we report that cobalt nano-particles supported on alumina nanofibers (Co/Al2O3) are acting as active nanocatalyst for catalytic hydrolysis of methylamine-borane. Co/Al2O3 nanocatalyst was fabricated by double-solvent method followed with wet-chemical reduction, and was characterized by utilizing various spectroscopic methods and imaging techniques. The results gathered from these analyses showed that the formation Al2O3 nanofibers supported cobalt(0) nanoparticles with a mean diameter of 3.9 +/- 1.2 nm. The catalytic feat of these cobalt nanoparticles was scrutinized in the catalytic hydrolysis of methylamine-borane by considering their activity and durability performances. They achieve releasing of 3.0 equivalent of H-2 via methylamine-borane hydrolysis at room temperature (initial TOF = 297 mol H-2/mol metal x h). Along with activity the catalytic durability of Co/Al2O3 was also studied by carrying out recyclability tests and it was found that these supported cobalt nanoparticles have good durability during the course of the catalytic recycles so that Co/Al2O3 preserves almost its innate activity at 5th catalytic recycle. The studies presented here also contains kinetic investigation of Co/Al2O3 catalyzed methylamine borane hydrolysis depending on the temperature, cobalt and methylamine borane concentrations, which were used to define rate expression and the activation energy of the catalytic reaction. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Complete 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, Mehmet
Hydrazine 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.
Copper(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, Murvet
Herein 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.
Development of a Pvc Membrane Potentiometric Sensor With Low Detection Limit and Wide Linear Range for the Determination of Maprotiline in Pharmaceutical Formulations
(Wiley-v C H verlag Gmbh, 2022) Tekce, Serkan; Subasi, Yaver; Coldur, Fatih; Kanberoglu, Gulsah Saydan; Zahmakiran, Mehmet
Maprotiline (MAP), is an active ingredient of some antidepressants which has been broadly used for the therapy of depression. The overdose of MAP in the treatment of patients with depression can lead to significant side effects, even lethal intoxication. Therefore, it is very important to develop simple, inexpensive, fast and reliable detection methods for MAP in interested samples. In our present study, we have offered a novel poly(vinylchloride) (PVC) membrane maprotiline-selective potentiometric sensor based on a type of MOFs, known as MIL-53(Al), as electroactive ionophore substance. The sensor prepared at the optimum membrane composition exhibited a linear response for maprotiline hydrochloride in the concentration range of 1,0x10(-9) M-1,0x10(-2) M with a slope of 59,1 mV/decade and detection limit of 9,0x10(-10) M. The pH working range of the sensor was determined as 2,0-9,5. The response time of the sensor was very fast and less than 5 s. With these performance features, it has been shown that the current sensor has quite superior features compared to the potentiometric MAP-selective sensor available in the literature. The potentiometric application of the sensor was successfully carried out with the detection of MAP in pharmaceutical tablets containing MAP-HCl.
Development of Mof-Based Pvc Membrane Potentiometric Sensor for Determination of Imipramine Hydrochloride
(Springer int Publ Ag, 2022) Subasi, Yaver; Kanberoglu, Gulsah S.; Coldur, Fatih; Cubuk, Osman; Zahmakiran, Mehmet
Imipramine hydrochloride (IMIP) is a tricyclic antidepressant utilized in the treatment of depression and chronic pain in some certain cases together with pain medication. The side effects of anxiety, insomnia, crying attacks, personality change and tachycardia are seen in imipramine overdose; therefore, determination of imipramine is an important issue. In this study, a novel potentiometric PVC membrane ion-selective sensor (ISE) was developed for monitoring of IMIP. MIL-53(Al) metal-organic framework was utilized for the first time as an electroactive material in the construction of imipramine-selective PVC membrane sensor. The sensor membrane consisting of 3.0% MIL-53(Al), 64.0% dibutylphthalate (DBP), 32.0% polyvinylchloride (PVC) and 1.0% potassium tetrakis(4-chlorophenyl)borate (KTpClPB) exhibited the most satisfied potentiometric performance characteristics. The sensor displayed a linear response for imipramine hydrochloride in the concentration range of 1.0 x 10(-7) M-1.0 x 10(-1) M with a slope of 57.7 mV/decade and detection limit of 5.0 x 10(-8) M. The operational pH range of the sensor was determined as 3.7-8.5. The sensor showed highly reproducible and stable potentiometric responses with the response time of less than 5 s. The IMIP content of a pharmaceutical used in the treatment of depression was successfully determined with the proposed imipramine-selective sensor. Additionally, the analytical applicability of the sensor in real biological samples was demonstrated by performing imipramine determinations in spiked human blood serum and urine samples. [GRAPHICS] .
The Development of Titanium Dioxide Nanotube-Supported Cdte Catalysts for Photocatalytic Enzymatic Glucose Fuel Cell and Response Surface Methodology Optimization
(Elsevier Science Sa, 2024) Caglar, Aykut; Pelen, Yucel Tuncbora; Ulas, Berdan; Zahmakiran, Mehmet; Kivrak, Hilal
Energy is one of the critical needs for human life and well-being. Alternative energy sources are essential due to the increase in energy demand with the rise in population the development of industrialization, and the damage caused by fossil fuels to the environment. Fuel cells, an alternative energy source, are a clean and environmentally friendly technology that converts chemical energy into electrical energy. In this study, titanium dioxide (TiO 2 ) nanotube (TNT)-support CdTe catalysts were synthesized by the wet impregnation (WI) method. Glucose oxidase (GOD) and laccase (LAC) enzymes were modified by incubation on CdTe/TNT catalysts. These enzymatic and non-enzymatic catalysts were characterized by scanning electron microscope-energy dispersive X-ray (SEMEDX) and mapping, X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscope (TEM) analyses. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) analyses were used to examine the activity, resistance, and stability of catalysts for enzymatic photocatalytic glucose electrooxidation. The 3 % CdTe(50-50)-TNT-GOD/GCE electrode exhibited the highest activity, resistance, and stability under UV illumination compared to other electrodes. The modification parameters of the electrodes, incubation time, amount of catalyst ink, and drying time were found to be 136.96 min, 8.94 mu L, and 21.30 min with response surface method (RSM) analysis, respectively. The estimated specific activity value was obtained as 0.754 mA/cm 2 under optimized conditions.
Dihydrogen Phosphate Stabilized Ruthenium(0) Nanoparticles: Efficient Nanocatalyst for the Hydrolysis of Ammonia-Borane at Room Temperature
(Mdpi Ag, 2015) Durap, Feyyaz; Caliskan, Salim; Ozkar, Saim; Karakas, Kadir; Zahmakiran, Mehmet
Intensive efforts have been devoted to the development of new materials for safe and efficient hydrogen storage. Among them, ammonia-borane appears to be a promising candidate due to its high gravimetric hydrogen storage capacity. Ammonia-borane can release hydrogen on hydrolysis in aqueous solution under mild conditions in the presence of a suitable catalyst. Herein, we report the synthesis of ruthenium(0) nanoparticles stabilized by dihydrogenphosphate anions with an average particle size of 2.9 +/- 0.9 nm acting as a water-dispersible nanocatalyst in the hydrolysis of ammonia-borane. They provide an initial turnover frequency (TOF) value of 80 min(-1) in hydrogen generation from the hydrolysis of ammonia-borane at room temperature. Moreover, the high stability of these ruthenium(0) nanoparticles makes them long-lived and reusable nanocatalysts for the hydrolysis of ammonia-borane. They provide 56,800 total turnovers and retain similar to 80% of their initial activity even at the fifth catalytic run in the hydrolysis of ammonia-borane at room temperature.
Electrochemical Sensing of Hydrogen Peroxide Using Pd@ag Bimetallic Nanoparticles Decorated Functionalized Reduced Graphene Oxide
(Pergamon-elsevier Science Ltd, 2018) Guler, Muhammet; Turkoglu, Vedat; Bulut, Ahmet; Zahmakiran, Mehmet
In this study, an excellent sensitive, selective, and stable electrochemical sensor was fabricated for the determination of hydrogen peroxide (H2O2) using nafion (Nf) and Pd@Ag bimetallic nanoparticles supported on (3-aminopropyl) triethoxysilane (APTES) functionalized reduced graphene oxide (rGO-NH2) modified glassy carbon (GC) electrode. The synthesized nanocomposites were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffractometer (XRD), and High-resolution transmission electron microscopy (HRTEM). The electrochemical properties of the nanocomposites were investigated by means of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Under optimized conditions, the electrochemical detection of H2O2 was carried out using amperometric method as well as CV. The linear range for H2O2 determination was 0.002-19.500 mM with a detection limit of 0.7 mu A and sensitivity of 1307.46 mu A mM(-1) cm(-2) due to the strong synergistic effect between Pd and Ag nanoparticles. The fabricated sensor was used for the determination of H2O2 in milk samples. The obtained results showed that the novel Nf/Pd@Ag/rGO-NH2/GC sensor can be used for the determination of H2O2 in real samples. (C) 2018 Elsevier Ltd. All rights reserved.
Electrochemical Sensing of Hydrogen Peroxide Using Pd@ag Bimetallic Nanoparticles Decorated Functionalized Reduced Graphene Oxide (Vol 263, Pg 118, 2018)
(Pergamon-elsevier Science Ltd, 2018) Guler, Muhammet; Turkoglu, Vedat; Bulut, Ahmet; Zahmakiran, Mehmet
An Electrochemical Sensing Platform With a Molecularly Imprinted Polymer Based on Chitosan-Stabilized Metal@metal-Organic Frameworks for Topotecan Detection
(Springer Wien, 2023) Mehmandoust, Mohammad; Tiris, Gizem; Pourhakkak, Pouran; Erk, Nevin; Soylak, Mustafa; Kanberoglu, Gulsah S.; Zahmakiran, Mehmet
The present study aims to develop an electroanalytical method to determine one of the most significant antineoplastic agents, topotecan (TPT), using a novel and selective molecular imprinted polymer (MIP) method for the first time. The MIP was synthesized using the electropolymerization method using TPT as a template molecule and pyrrole (Pyr) as the functional monomer on a metal-organic framework decorated with chitosan-stabilized gold nanoparticles (Au-CH@MOF-5). The materials' morphological and physical characteristics were characterized using various physical techniques. The analytical characteristics of the obtained sensors were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). After all characterizations and optimizing the experimental conditions, MIP-Au-CH@MOF-5 and NIP-Au-CH@MOF-5 were evaluated on the glassy carbon electrode (GCE). MIP-Au-CH@MOF-5/GCE indicated a wide linear response of 0.4-70.0 nM and a low detection limit (LOD) of 0.298 nM. The developed sensor also showed excellent recovery in human plasma and nasal samples with recoveries of 94.41-106.16 % and 95.1-107.0 %, respectively, confirming its potential for future on-site monitoring of TPT in real samples. This methodology offers a different approach to electroanalytical procedures using MIP methods. Moreover, the high sensitivity and selectivity of the developed sensor were illustrated by the ability to recognize TPT over potentially interfering agents. Hence, it can be speculated that the fabricated MIP-Au-CH@MOF-5/GCE may be utilized in a multitude of areas, including public health and food quality.