Browsing by Author "Sahin, Omer"

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Applications on Agricultural and Forest Waste Adsorbents for the Removal of Lead (Ii) From Contaminated Waters
(Springer, 2012) Saka, Cafer; Sahin, Omer; Kucuk, Mehmet Masuk
At present, there is growing interest in using low cost, commercially available materials for the adsorption of heavy metals. The major advantages of adsorption technologies are its effectiveness in reducing the concentration of heavy metal ions to very low levels and the use of inexpensive adsorbent materials. In this review, agricultural and forest waste adsorbents were used to remove Pb2+ ions in wastewater treatment, and their technical feasibilities were reviewed in studies mainly from 2000 to 2010. They all were compared with each other by metal binding capacities, metal removal performances, sorbent dose, optimum pH, temperature, initial concentration and contact time. Although commercial activated carbon is widely used in wastewater treatment applications, it has high costs. The use of agricultural by-products as adsorbent material to purify heavy metal contaminated water has become increasingly popular through the past decade because they are less expensive, biodegradable, abundant and efficient. Instead of activated carbon, this study was focused on the inexpensive materials such as agricultural and forest waste. It was shown that these alternative adsorbents had sufficient binding capacity to remove Pb2+ ions from wastewater.
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.
The Characterization and Sodium Borohydride Electrooxidation of Novel Carbon Nanotube Supported Copromoted Pd as Anode Catalyst for Fuel Cell
(Wiley, 2022) Caglar, Aykut; Hansu, Tulin A.; Sahin, Omer; Kivrak, Hilal
In the present study, the effect of Co addition on Pd is investigated. Pd/CNT and PdCo/CNT catalysts are prepared via the sodium borohydride (SBH, NaBH4) reduction method. The X-ray diffraction, transmission electron microscope, and inductively coupled plasma-mass spectrometry analyses are performed to characterize the PdCo(70-30)/CNT catalyst. These characterization results reveal that Pd/CNT and PdCo/CNT catalysts are prepared successfully. NaBH4 electrooxidation activities of PdCo/CNT catalysts are examined with electrochemical methods such as cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. PdCo(70-30)/CNT catalyst has 11.52 mA/cm(2) specific activity, 477.18 m(2)/g electrochemical active surface area, and the best electrochemical stability. Pd is a promising catalyst for NaBH4 electrooxidation reaction.
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 Comparative Study for Sodium Borohydride Dehydrogenation and Electrooxidation on Cerium and Cobalt Catalysts
(Health & Environment Assoc, 2020) Hansu, Tulin Avci; Caglar, Aykut; Sahin, Omer; Kivrak, Hilal
In the present study, Co/CNT and Ce/CNT catalysts are prepared via sodium borohydride (NaBH4) reduction method. Co/CNT and Ce/CNT catalysts are examined to the dehydrogenation and electrooxidation of NaBH4. NaBH4 dehydrogenation activities of these Co/CNT and Ce/CNT catalysts are performed in alkaline environment. 5% Co/CNT catalyst exhibits superior hydrogen evolution compared with other catalysts. Activation energy is calculated using Arrhenius equation. Initial rate for this catalyst is found as 1700 ml H-2 g(cat)(-1) min(-1). As a result of the kinetic calculations, the activation energy of the catalyst is calculated as 44,68775 kj/mol. The degree of reaction (n) is found to be 0.5 by trial and error. In conclusion, 5% Co/CNT catalyst is a promising catalyst for hydrogen production from NaBH4. Cyclic voltammetry (CV) analysis is utilized to examine the electrochemical activity of the catalysts for NaBH4 electrooxidation. 0.1% Co/CNT catalyst has 0.38 mA cm(-2) (3181 mA mg(-1) Co) specific activity.
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)).
Enhanced Electrochemical Double-Layer Capacitive Performance With Co2 Plasma Treatment on Activated Carbon Prepared From Pyrolysis of Pistachio Shells
(Pergamon-elsevier Science Ltd, 2020) Sahin, Omer; Yardim, Yavuz; Baytar, Orhan; Saka, Cafer
This study reports an original approach based on the CO2 plasma treatment on modification of the chemical or physical properties of activated carbon(AC) from the pistachio shells as a waste for application as electrochemical double-layer capacitors(EDLC). In the AC production experiments, impregnation ratio, impregnation pre-treatment temperature, activation temperature and activation time are investigated. In the AC modification experiments with plasma treatment, the effects of plasma gases, plasma power and plasma time are performed. The results of the different conditions indicated that the structural properties of the obtained AC were significantly dependent on the plasma and pyrolysis parameters. The surface properties of the raw AC and plasma-treated AC (PTAC) with X-ray photoelectron spectroscopy (XPS), nitrogen adsorption technique, and scanning electron microscope (SEM) are characterized. Surface area values for the raw AC and PTAC are 768 and 1250 m(2) g(-1), respectively. A change in the peak positions and an increase in the percentage of oxygen of the AC treated with CO2 plasma were obtained from XPS results. After 15 min of CO2 plasma activation, a significant increase in the capacitance of up to about 141% was obtained as a 118.4 F g(-1) compared to 49.98 F g(-1) for untreated AC. The results show that the plasma treatment on the specific surface area and surface functional groups of AC has a significant impact. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
High Hydrogen Production Rate From Potassium Borohydride Hydrolysis With an Efficient Catalyst: Cnt@ru(0)
(Elsevier Science inc, 2022) Keskin, M. Salih; Agirtas, Mehmet Salih; Baytar, Orhan; Izgi, M. Sait; Sahin, Omer; Horoz, Sabit
We describe the production and catalytic activity of a carbon nanotube supported-Ru(0) (CNT@Ru(0)) catalyst. For the first time, the produced CNT@Ru(0) catalyst is used to achieve the greatest hydrogen production rate from potassium borohydride (KBH4) hydrolysis. The produced CNT@ Ru(0) catalyst shows promise in the creation of hydrogen from the degradation of KBH4. The hydrogen generation rate of CNT@Ru(0) is determined to be 86,264.85 mL min(-1) can with a low activation energy of 30.18 kJ mol(-1). CNTs are potential support for distributing metal catalysts, according to the current work. Furthermore, structural, morphological, and elemental characteristics of the produced CNT@Ru(0) catalyst are investigated.
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.
Hydrolysis and Electrooxidation of Sodium Borohydride on Novel Cnt Supported Cobi Fuel Cell Catalyst
(Elsevier Science Sa, 2020) Hansu, Tulin Avci; Caglar, Aykut; Sahin, Omer; Kivrak, Hilal
At present, Co, Bi, CoBi, and CoBi/CNT catalysts are prepared via co-precipitation method and sodium borohydride (NaBH4) reduction method for NaBH4 electrooxidation and hydrolysis. These Co, Bi, and CoBi catalysts are characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), N-2 adsorption-desorption, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and Temperature Programmed Reduction (TPA). These catalysts are employed for NaBH4 hydrolysis and further measurements are performed to investigate their NaBH4 electrooxidation activity. For NaBH4 hydrolysis, NaOH concentration, reaction temperature, NaBH4 concentration, and catalyst amount are optimized for CoBi and CoBi/CNT catalysts. Furthermore, the rate constants (k) are found between 20 and 50 degrees C and the activation energy is calculated from the Arrhenius equation. The hydrogen generation rates on CoBi (95-5) and % 10 CoBi (95-5)/CNT catalysts are found as 2605.6ml H-2 g(-1)cat min(-1) and 12996 ml H-2 g(-1)cat min(-1), respectively. NaBH4 electrooxidation is investigated with cyclic voltammetry (CV), chronoampemmetry (CA), and electrochemical impedance spectroscopy (EIS) measurements. Maximum mass activities are obtained as 5.86 mA mg(-1) Co for CoBi and 25.7 mA mg(-1) Co for CoBi/CNT catalysts. EIS and CA results are also in a good agreement with CV results in terms of stability and electrocatalytic activity of CoBi/CNT catalyst. The CoBi/CNT catalyst is believed to be a promising anode catalyst for the direct borohydride fuel cell (DBFC).
Improvement of Electrochemical Double-Layer Capacitance by Fast and Clean Oxygen Plasma Treatment on Activated Carbon as the Electrode Material From Walnut Shells
(Pergamon-elsevier Science Ltd, 2020) Saka, Cafer; Baytar, Orhan; Yardim, Yavuz; Sahin, Omer
In this study, a simple, fast, and clean oxygen plasma method is presented to increase the surface area of activated carbon from walnut shells (WAC) and to connect functional groups containing oxygen to the carbon sample surface. X-ray photoelectron spectroscopy (XPS), nitrogen adsorption technique, Fourier-transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), and scanning electron microscope (SEM) analyses to investigate the properties of the WAC and WACP are performed. Cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) measurements are used to investigate the capacitance properties of the supercapacitors. A significant increase in the surface area of the WAC was increased from 22 m(2) g(-1) to 78 m2 g(-1) after oxygen plasma treatment. The specific capacitance was improved from 6.98 F g(-1) to 76.89 F g(-1) at 2.5 mV s(-1). The devices with functionalized electrodes exhibited cyclic stability of 78% after 5000 cycles.
Iodine Adsorption and Electrochemical Double-Layer Capacitor Characteristics of Activated Carbon Prepared From Low-Cost Biomass
(Taylor & Francis inc, 2023) Saka, Cafer; Yardim, Yavuz; Sahin, Omer; Baytar, Orhan
The efficient adsorption application and electric double-layer capacitor material with low-cost biomass-based activated carbon materials have been quite common recently. In this study, chestnut shell-based activated carbons were produced by chemical activation. ZnCl2, H3PO4, and KOH agents were used for chemical activation. The obtained activated carbon, iodine adsorption from aqueous solutions, and its use as an electro capacitor were investigated. The scanning electron microscope, nitrogen adsorption/desorption, and Fourier transform infrared spectroscopy were used for characterization. The values of surface area and iodine adsorption capacity of the chestnut shell-based activated carbon are 1544 m(2) g(-1) and 1525 mg g(-1). As a result, a specific capacitance of 97 Fg(-1) with chestnut shell-based activated carbon was obtained in a 1 M KCl electrolyte for the electrochemical double-layer capacitor. This study shows that activated carbon based on the chestnut shell can be used both as an electrochemical energy storage material and as an adsorbent in iodine adsorption.
Mistakes and Misconceptions of Elementary School Students About the Concept of 'variable
(Elsevier Science Bv, 2011) Sahin, Omer; Soylu, Yasin
Since the concept of 'variable' requires abstract thinking ( epistemological) and because of the difficulties in teaching this concept ( pedagogical) and approaches of the students towards the concept of 'variable' ( psychological), misconceptions and mistakes occur in teaching this concept. The purpose of this study is to detect the mistakes and misconceptions of the students about the concept of 'variable' along with the reasons for these mistakes and misconceptions and to classify these mistakes and misconceptions. In this regard, the sample of the study is composed of 50 seventh-grade students from Gazi Elementary School which is located in A city center. A test, which is composed of 8 open-ended questions, has been applied in the research in order to collect data. This test has been presented to the students in order to determine the mistakes and misconceptions of the students about the concept of 'variable'. Upon the analysis of the data obtained from the test, the mistakes and misconceptions of the students about the concept of 'variable' have been detected, and these mistakes and misconceptions have been classified in certain categories
Novel Approach To Study Dispersion in Growth and Dissolution Rate of Crystals From Solutions
(Elsevier, 2019) Kaya, Mustafa; Ceyhan, Ayhan Abdullah; Abut, Serdar; Sahin, Omer
Growth and dissolution rate dispersion of boric acid single crystal was investigated in supersaturated and undersaturated solution contained in a specially designed cell by in situ examination of crystals mounted at the tip of a needle, rotated between 0 degrees and 360 degrees, and using an image analyzer system. Changes in the behavior of equivalent crystal diameters at different supersaturation and undersaturation and rotation angles were determined by using two new procedures: (1) rotating growing or dissolving crystals by 360 degrees at intervals of 45 degrees (Procedure 1: angular growth/dissolution rates), and scanning individual face at increments of 10 degrees in the 360 degrees range (Procedure 2: point growth/dissolution rates). It was found that: (1) dispersion in angular growth and dissolution rates is a general phenomenon due to different growth and dissolution rates of individual faces of a crystal, but this dispersion is reduced when the average growth and dissolution rates of all faces are taken into account, and (2) the point growth/dissolution rates of single crystal, calculated by procedure 2, are different from point to point.
Preparation and Characterization of Activated Carbon From Pine Cone by Microwave-Induced Zncl2 Activation and Its Effects on the Adsorption of Methylene Blue
(Springer, 2014) Ozhan, Abdurrahman; Sahin, Omer; Kucuk, Mehmet Masuk; Saka, Cafer
In this work, activated carbon prepared from pine cone (PCAC) with ZnCl2 as an activation agent under microwave radiation was investigated. The activation step was performed at the microwave input power of 400 W and radiation time of 5 min. The properties of activated carbon were characterized by N2 adsorption Brunauer-Emmett-Teller (BET), scanning electron microscopy and Fourier transform infrared spectroscopy. Results showed that the BET surface area, Langmuir surface area, and total pore volume of PCAC were 939, 1,486 m(2)/g and 0.172 cm(3) / g, respectively. Adsorption capacity was demonstrated by the iodine numbers. The adsorptive property of PCAC was tested using methylene blue dye. Equilibrium data was best fitted by the Langmuir isotherm model, showing a monolayer adsorption capacity of 60.97 mg/ g. The pseudo-first-and pseudosecond- order kinetic models were examined to evaluate the kinetic data, and the rate constants were calculated. Adsorption of the dyes followed pseudo-first order kinetics. Thermodynamic parameters such as free energy, enthalpy and entropy of dye adsorption were obtained.
A Remarkable Mo Doped Ru Catalyst for Hydrogen Generation From Sodium Borohydride: the Effect of Mo Addition and Estimation of Kinetic Parameters
(Springer, 2020) Hansu, Tulin Avci; Sahin, Omer; Caglar, Aykut; Kivrak, Hilal
At present, carbon nanotube supported monometallic Ru at 3 wt% Ru loading (3% Ru/CNT) per gram support and bimetallic RuMo at 3 wt% Ru loading per gram support (3% Ru-Mo/CNT) at varying Ru:Mo atomic ratios are synthesized via sodium borohydride (NaBH4) reduction method to investigate their performance towards NaBH4 hydrolysis. These monometallic Ru/CNT and bimetallic Ru:Mo/CNT catalysts prepared at varying Ru:Mo atomic ratios are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), and transmission electron microscopy (TEM). Characterization results reveal that Mo addition to Ru alters the electronic state of the catalysts. The NaOH concentration, the amount of catalyst, the NaBH4 concentration and the temperature parameters that affect the hydrolysis rate of this synthesized and developed catalyst were examined. The kinetic calculations of these parameters related to the order of the reaction were determined. Under optimum conditions catalyst hydrogen production rate was found to be 82,758.43 ml H-2 g(cat)(-1) min(-1). The reaction order (n) and activation energy (E-a) are determined as 0.42 and 35.11 kJ mol(-1). Ru:Mo/CNT catalyst is a novel and promising catalyst for hydrogen generation from NaBH4.
Structure of Ruthenium Nanocatalysts of Bismuth, Investigation of Its Effect on Hydrolysis Performance and Kinetic Studies
(Wiley, 2021) Avci Hansu, Tulin; Caglar, Aykut; Demir Kivrak, Hilal; Sahin, Omer
In this study, a new nanocatalyst, RuBi/carbon nanotube, was synthesized to be used in the hydrolysis reaction of sodium boron hydride. The sodium boron hydride hydrolysis performance was investigated by adding bismuth to the structure of ruthenium nanocatalysts. Hydrolysis experiments were carried out by adding bismuth at different atomic proportions to ruthenium. The best atomic ratio was determined to be 90:10. These catalysts are characterized by scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffraction, and transmission electron microscopy. The parameters affecting hydrolysis such as temperature, catalyst amount, sodium hydroxide concentration, and sodium borohydride concentration were examined. The reusability of the catalyst was tested five times. In the calculations, the reaction order was calculated as n, 0.73, and activation energy E-a, 49657 kJ/mol.
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.