Browsing by Author "Izgi, Mehmet Sait"

Now showing 1 - 8 of 8

Ceo2 Supported Multimetallic Nano Materials as an Efficient Catalyst for Hydrogen Generation From the Hydrolysis of Nabh4
(Pergamon-elsevier Science Ltd, 2020) Izgi, Mehmet Sait; Baytar, Orhan; Sahin, Omer; Kazici, Hilal Celik
Nowadays, there is still no suitable method to store large amounts of energy. Hydrogen can be stored physically in carbon nanotubes or chemically in the form of hydride. In this study, sodium borohydride (NaBH4) was used as the source of hydrogen. However, an inexpensive and useful catalyst (Co-Cr-B/CeO2) was synthesized using the NaBH4 reduction method and its property was characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), x-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) measurements. The optimized Co-Cr-B/CeO2 catalyst exhibited an excellent hydrogen generation rate (9182 mLg(metal)(-1) min(-1)) and low activation energy (35.52 kJ mol(-1)). The strong catalytic performance of the Co-Cr-B/CeO2 catalyst is thought to be based on the synergistic effect between multimetallic nanoparticles and the effective charge transfer interactions between the metal and the support material. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Co-Mn Nanoparticles Supported on Epoxy-Based Polymer as Catalyst for Evolution of H2 From Ammonia Borane Semi-Methanolysis
(Springer, 2022) Kazici, Hilal Celik; Izgi, Mehmet Sait; Sahin, Omer
A high-density and low-cost hydrogen generation technology is required for hydrogen energy systems. Non-noble multimetallic Co-Mn-B nanoparticles can serve as a good catalyst because of their low cost and ability to produce hydrogen gas during the catalytic semi-methanolysis process. This work reports the synthesis, characterization, and the use of Co-Mn-B catalyst supported on Eupergit CM as a very active and reusable catalyst for the generation of hydrogen from the semi-methanolysis of ammonia borane (AB). Solid materials were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDX), and scanning electron microscopy (SEM). Rates of hydrogen generation were used to determine the kinetics of semi-methanolysis reaction. The parameters examined, namely the percentage of NaOH, percentage of metal loading, amount of catalyst particles, and AB concentrations and temperatures, were 1-5 (wt)%, 5-10 (wt)%, 5-50 mg, 0.5-3 mmol, and 30-60 degrees C, respectively. Total turnover frequency (TOF) value, hydrogen generation rate, and activation energy (Ea) were obtained at 30 degrees C as 15,751 h(-1), 17,324 mL g(cat)(-1)min(-1) (3 mmol AB and 25 mg Co-Mn-B/Eupergit CM), and 43.936 kJ mol(-1), respectively.
A Comprehensive Study on the Synthesis, Characterization and Mathematical Modeling of Nanostructured Co-Based Catalysts Using Different Support Materials for Ab Hydrolysis
(Springer international Publishing Ag, 2021) Kazici, Hilal Celik; Izgi, Mehmet Sait; Sahin, Omer
The present work includes the synthesis of aluminum oxide (Al2O3), multi-walled carbon nanotube (MWCNT), and Eupergit CM-supported Co-based nanoparticles (Co-Fe-B and Co-Mn-B), and the investigation of their hydrolytic efficiency in H-2 generation from the catalytic hydrolysis of ammonia borane (NH3BH3). Among the supported catalysts, Co-Fe-B/Eupergit CM exhibited the highest H-2 generation rate as 4539 mLmin(-1)g(catalyst)(-1) compared to Co-Fe-B/Al2O3 and Co-Fe-B/MWCNT, which exhibited 4373 mLmin(-1)g(catalyst)(-1) and 3294 mLmin(-1)g(catalyst)(-1), respectively. When Co-Mn-B/ Eupergit CM was used instead of Co-Fe-B/ Eupergit CM, a significant increase in the highest HGR (19.422 mLmin(-1)g(catalyst)(-1)) was found. Moreover, turnover frequency (TOF) value was calculated as 318 h(-1) and 646 h(-1) for Co-Fe-B/Eupergit CM and Co-Mn-B/Eupergit CM, respectively.
Effect of Plasma Pretreatment of Co-Cu Catalyst on Hydrogen Generation From Sodium Borohydride Methanolysis
(Springer, 2021) Sahin, Omer; Izgi, Mehmet Sait; Tayboga, Seda; Kazici, Hilals Celik
This work reports the preparation and catalytic use of Co-Cu-B nanoparticles, as catalyst for hydrogen generation from the methanolysis of sodium borohydride (NaBH4). An inexpensive and useful catalyst was characterized using a combination of advanced analytical methods including by X-ray diffraction, energy dispersive X-ray spectroscopy, F-TIR analysis, scanning electron microscopy and Brunauer-Emmett-Teller to produce hydrogen from NaBH4 in the reaction with methanol. Basically, after the synthesis of the catalysts, catalytic activity enhancement experiments were carried out by plasma and microwave irradiation. It was determined that the catalyst that is irritiated with plasma is more active on the hydrogen production rate.". The maximum hydrogen production rate in the presence of 2.5 wt% NaBH4 was 270 mL g(-1) min(-1) for catalyst irradiated in the plasma. Our report also includes the comparison of kinetic study of the catalytic methanolysis of NaBH4 depending on irritated and non-irritable Co-Cu-B catalyst in plasma medium. It was observed that the activation energy of the catalyst irradiated in the plasma (Ea = 10.835 kJ mol(-1)) was significantly lower than the non-irritable catalyst (Ea = 68.18 kJ mol(-1)).
Hydrogen Production by Using Ru Nanoparticle Decorated With Fe3o4@sio2-Nh2 Core-Shell Microspheres
(Pergamon-elsevier Science Ltd, 2020) Izgi, Mehmet Sait; Ece, M. Sakir; Kazici, Hilal Celik; Sahin, Omer; Onat, Erhan
Noble metals are commonly used in order to accelerate the NH3BH3 hydrolysis for H2 production as heterogeneous catalysts. The nanoparticles (NPs) of these metals can be applied as active catalysts in fluid reactions. Metal NPs included in the core-shell nano- structures emerged as well-defined heterogeneous catalysts. Additionally, unsupported NPs catalysts can be gathered easily among neighboring NPs and the separation/recovery of these catalysts are not efficient with traditional methods. For this reason, here, silica-shell configuration was designed which was functionalized with a magnetic core and amine groups and Ru NPs were accumulated on Fe3O4@SiO2-NH2 surface for H-2 production from NH3BH3. Fe3O4@SiO2-NH2-Ru catalysts demonstrated high catalytic activity as long as it has a hydrogen production rate of 156381.25 mLg(cat)(-1)min(-1) and a turnover frequency (TOF) of 617 mol(H2) mol(cat)(-1)min(-1) towards the hydrolysis dehydrogenation of AB at 30 degrees C. This result is significantly higher than most of the known catalysts. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Hydrogen Production Through the Cooperation of a Catalyst Synthesized in Ethanol Medium and the Effect of the Plasma
(Taylor & Francis inc, 2023) Izgi, Mehmet Sait; Onat, Erhan; Kazici, Hilal Celik; Sahin, Omer
In the present study, nanostructured Ni-B catalysts were successfully prepared in ethanol medium using the chemical reduction method for hydrogen production from the catalytic hydrolysis of sodium borohydride (NaBH4). Ni-B nanostructures were characterized by several analysis methods including XRD, SEM/EDS, FT-IR and BET. The effects of factors such as solution temperature, NaBH4 loadings, catalyst amount and NaOH concentration on the performance of these catalysts in the production of hydrogen from alkaline NaBH4 solutions were investigated in detail. In addition, the Ni-B catalyst prepared in ethanol medium and subjected to plasma for the hydrogen production from the catalytic hydrolysis of NaBH4 was investigated. The Ni-B catalyst prepared in ethanol medium showed maximum hydrogen production rate (1000 mL min(?1)gcatalyst(?1)) which was approximately 2 times higher than the rate obtained from the Ni-B catalyst prepared in water (400 mL min(?1)gcatalyst(?1)) and acethone (550 mL min(?1)gcatalyst(?1)). The Ni-B nanoparticles showed the best catalytic activity at 333?K with a maximum hydrogen production rate of 7134 mL min(?1)gcatalyst(?1) and activation energy of 46.83?kJmol(?1) for the NaBH4 hydrolysis reaction in the Ni-B catalysts prepared in ethanol and subjected to plasma. As the Ni-B catalyst is inexpensive and easy to prepare, it is feasible to use this catalyst in the construction of practical fuel cells for portable and in situ applications.
Novel Activated Carbon Supported Trimetallic Pdcoag Nanoparticles as Efficient Catalysts for the Hydrolytic Dehydrogenation of Ammonia Borane
(Pergamon-elsevier Science Ltd, 2019) Kazici, Hilal Celik; Yildiz, Fikret; Izgi, Mehmet Sait; Ulas, Berdan; Kivrak, Hilal
Activated carbon (AC) supported palladium, cobalt and silver nanoparticle (PdCoAg/AC) catalysts were prepared by in situ reduction of sodium borohydride (NaBH4) and characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The PdCoAg/AC catalyst is active in the hydrolysis of ammonia-borane (AB) even at low temperatures. Compared with mono- (Pd) and bi-metallic (PdCo) nanoparticles, this trimetallic (PdCoAg) structure showed greatly increased catalytic activity for AB hydrolysis. Their hydrolysis completion time was 50 s. This study also included full experimental details of kinetic data to determine the activation parameters (Ea, Delta H and Delta S) for the rate law and the catalytic hydrolysis of AB. In addition, the PdCoAg/AC catalysts had favorable catalytic activity also after seven runs. Hydrogen generation rate (HG), Ea, Delta H and Delta S were obtained at 25 degrees C as 4666.66 mL min(-1)g(-1) (2 mmol AB and 50 mg PdCoAg/AC), 26.836 kJ mol(-1), 29.416 kJ mol(-1) and -108.42 J mol(-1)K(-1), respectively. In addition, the study showed that Pd0.6Co0.2CAg0.2/AC (Pd:Co:Ag atomic ratio = 6:2:2) showed the total turnover frequency (TOF) value of 6624 h(-1). These results demonstrate that the PdCoAg/AC catalyst is a promising alternative in search of the practical application of AB as a hydrogen storage material for fuel cell applications. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Synthesis of Metal-Oxide Triple Nano Catalysts and Application To H2 Production and H2o2 Oxidation
(Springer, 2020) Kazici, Hilal Celik; Salman, Firat; Izgi, Mehmet Sait; Sahin, Omer
Magnesium oxide (MgO)-supported nanocatalysts are a highly insulating crystalline solid with a sodium chloride crystal structure and excellent properties including chemical inertness, high temperature stability and high thermal conductivity. Here, a ternary alloy catalyst of MgO-supported CoMoB was synthesized by means of a chemical reduction method using ethylene glycol solution. The prepared CoMoB/MgO catalysts were characterized using x-ray diffraction, scanning electron microscopy (SEM/EDX) and Fourier transform infrared spectroscopic analysis. The CoMoB/MgO nanocomposite served as the enabling platform for a range of applications including hydrogen production catalyst and hydrogen peroxide (H2O2) determination. It also showed a high hydrogen production rate (1000 mLgcat-1 min(-1)) and low activation energy (68.319 kJ mol(-1)) for the hydrolysis of ammonia borane. Additionally, the electro-oxidation performance of the CoMoB/MgO for H2O2 detection was studied by cyclic voltammetry and chronoamperometry. The CoMoB/MgO sensor demonstrated a wide linear range up to 10 mM with a detection limit of 3.3 mu M.