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Öğe A dual functional material: Spirulina Platensis waste-supported Pd-Co catalyst as a novel promising supercapacitor electrode(Elsevier Sci Ltd, 2021) Karakas, Duygu Elma; Akdemir, Murat; Atabani, A. E.; Kaya, MustafaIn the present study, Spirulina Platensis waste-supported Pd-Co (SPW-Pd-Co) catalyst was used as an efficient catalyst for the methanolysis reaction of sodium borohydride (NaBH4); moreover, the produced SPW-Pd-Co catalyst was tested as a supercapacitor electrode material for the first time. In this context, the SPW-Pd-Co catalyst was synthesized by the treatment of the Spirulina Platensis waste (SPW) with 1-7 M HCl, 1 mL PdCl2 solution (2% w/w) and 1, 2, 3, 4, and 5 mL CoCl2 center dot 6H(2)O solution (5% w/w). Under optimum conditions, the most active catalyst was obtained by burning with 3 M HCl-Pd-4 mL Co2+ solution at 600 degrees C for 90 min. The maximum rate of hydrogen generation (HGR) obtained at 30 degrees C from the NaBH4 methanolysis reaction was found to be 5497.7 mLmin(-1) gcat(-1), and the catalyst activation energy was found to be 10.32 kJ mol(-1). The gravimetric capacitance of the prepared electrode was calculated as 50 F/g at 2 A/g current density. The capacitance values of the supercapacitor are at a significant level in terms of capacity and the cost.Öğe A novel cost-effective catalyst from orange peel waste protonated with phosphoric acid for hydrogen generation from methanolysis of NaBH4(Pergamon-Elsevier Science Ltd, 2022) Karakas, Duygu ElmaIn this study, orange peel (OP), one of the organic wastes, was first used as a metal-free catalyst for the production of hydrogen from sodium boron hydride (NaBH4). In order to prepare an orange peel catalyst (OP-H3PO4-Cat) with the best catalytic activity, experiments were carried out on pure orange peel with different acid types, different burning temperatures and different burning times. As a result of these experiments, it was determined that OP-H3PO4-Cat treated with 30% H3PO4 and burned at 400 degrees C for 45 min had the best catalytic activity. The OP-H3PO4-Cat material was characterised by several techniques such as FTIR, XRD and SEM. As a result, the hydrogen generation rates (HGR) at 30 degrees C and 60 degrees C in the methanolysis reaction of 2.5% NaBH4 catalysed by OP-H3PO4-Cat were found as 45,244 and 61,892 mLmin(-1)g.cat(-1), respectively. The activation energy of OP-H3PO4-Cat catalyst was calculated as 12.47 kJmol(-1). (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Application of Half-Sandwich Metal-Phosphinite Compounds to Biological Activities: Determine the energies of the HOMO and LUMO levels(Wiley-V C H Verlag Gmbh, 2023) Meric, Nermin; Rafikova, Khadichakhan; Zazybin, Alexey; Guzel, Remziye; Kayan, Cezmi; Karakas, Duygu Elma; Dundar, AbdurrahmanMononuclear transition metal complexes 1-(furan-2-yl)ethyldiphenyl[dichloro(eta(6)-p-cymene)ruthenium(II)]phosphinite, (2), 1-(furan-2-yl)ethyldiphenyl[dichloro(eta(6)-benzene) ruthenium(II)] phosphinite (3), 1-(furan-2-yl)ethyldipheny[chloro(eta(4)-1,5-cyclooctadiene)rhodium(I)]phosphinite (4), 1-(furan-2-yl)ethyldiphenyl[dichloro (eta(5)pentamethylcyclopentadienyl)iridium (III)] phosphinite (5) were synthesized and characterized by microanalysis, infrared, MS, and NMR spectroscopy. The biological activities of the complexes were also tested. Compounds 2 and 5 were the best complexes at DPPH radical scavenging and reducing power activity at 73.27 % and 0.41 at 200 mu g/mL, respectively. The highest antimicrobial activity exhibited by complex 3 as 14 mm inhibition zone against S. aureus. All of the complexes have cleaved the DNA from the double-strand and exhibited three bands on gel electrophoresis. Moreover, cyclic voltammetry studies of the phosphinite complexes were carried out to determine the energies of the HOMO and LUMO levels as well as to estimate their electrochemical and some electronic properties.Öğe Asymmetric transfer hydrogenation of alkyl/aryl or alkyl/methyl ketones catalyzed by known C2-symmetric ferrocenyl-based chiral bis(phosphinite)-Ru(II), Rh(I) and Ir(III) complexes(Elsevier Science Sa, 2016) Durap, Feyyaz; Karakas, Duygu Elma; Ak, Bunyamin; Baysal, Akin; Aydemir, MuratKnown Ru(II), Rh(I) and Ir(III) complexes of C-2-symmetric ferrocenyl based chiral bis(phoshinite) ligands were catalyzed the asymmetric transfer hydrogenation of alkyl/aryl or alkyl methyl ketones. Corresponding secondary alcohols were obtained with high enantioselectivities up to 98% ee and reactivities using iso-propanol as the hydrogen source. (C) 2016 Elsevier B.V. All rights reserved.Öğe Biomass-based metal-free catalyst as a promising supercapacitor electrode for energy storage(Springer, 2022) Karakas, Duygu Elma; Akdemir, Murat; Imanova, Gunel T.; Kivrak, Hilal Demir; Horoz, Sabit; Kaya, MustafaIn present study, biomass doped H3PO4-Cat, named as STW-H3PO4-Cat, was used as a catalyst in the methanolysis of sodium borohydride (NaBH4). Spent tea waste (STW) was used for the first time in this study as biomass. The generated existing catalyst was also employed as an active supercapacitor material, demonstrating its dual function. To identify the most active catalyst in the methanolysis of sodium borohydride, the catalyst was functionalized in different H3PO4 concentrations (1-7 M), and different annealing temperatures (200-500 degrees C) and different annealing times (20-80 min). Optimum parameters were determined as 7 M H3PO4, 400 degrees C, and 40 min. The maximum hydrogen production (HPR) value and the activation energy (E-a) were determined as 76,640 mL min(-1) g cat(-1) and 12.03 kJ mol(-1). When the catalyst was investigated in terms of the supercapacitor, the electrode's capacitance at 1 A/g current intensity was found to be 158 F/g utilizing the charge-discharge curve. The catalyst with optimum conditions was structurally and morphologically characterized by Fourier Transform Infrared (FTIR), x-ray diffraction (XRD), and scanning electron microscope (SEM) measurements, respectively.Öğe Catalytic activites of a biomaterial (sumac) catalyst in sodium borohyride methanolysis reactions(Elsevier, 2023) Karakas, Duygu Elma; Kaya, Mustafa; Horoz, SabitBiomass waste (sumac) in particular, is an excellent starting point for preparing carbon materials since it is abundant, inexpensive, environmentally beneficial, and renewable. Therefore, the aim of the present study is defatted sumac (DS)-hydrochloric acid (HCl)-cobalt (Co) (DS-HCl-Co) catalyst (it will be used as a catalyst for the first time) in the presence of low activation energy and high hydrogen production rate (HPR). The effect of different parameters such as amount of catalyst, concentration of NaBH4 and tem-perature on HPR value obtained as a result of NaBH4 methanolysis in the presence of DS-HCl-Co catalyst have been investigated. The synthesized catalysts are named DS-HCl (pure) and DS-HCl-Co (supported). While the HPR value (mL*gcat -1 *min -1) obtained as a result of the hydrolysis experiments carried out is 3516.16 for the DS-HCl catalyst, it is 8298.5 for the DS-HCl-Co catalyst. Thus, it should be noted that the HPR value increases approximately 2.36 times in the presence of support material. Our other motivation in the current study is to have low activation energy, which is an important factor that increases catalytic activity. Using the Arrhenius equation, the activation energy for the DS-HCl-Co catalyst is calculated as 31.67 kJ/mol and this value is lower than some reported values when compared to the literature. As a result, it can be said that the DS-HCl-Co catalyst is a unique, inexpensive, and ideal catalyst with high activity values for hydrogen production from alkali hydrides.(c) 2022 Elsevier B.V. All rights reserved.Öğe Chiral C2-symmetric ?6-p-cymene-Ru(II)-phosphinite complexes: Synthesis and catalytic activity in asymmetric reduction of aromatic, methyl alkyl and alkyl/aryl ketones(Elsevier Science Sa, 2018) Karakas, Duygu Elma; Aydemir, Murat; Durap, Feyyaz; Baysal, AkinChiral C-2-symmetric bis(phosphinite) ligands and their binuclear ruthenium(II) complexes have been synthesized and used as catalysts in the ruthenium-catalyzed asymmetric transfer hydrogenation of aromatic, methyl alkyl and alkyl/aryl ketones using 2-propanol as both the hydrogen source and solvent in the presence of KOH. Under optimized conditions, all complexes showed high catalytic activity as catalysts in the reduction of various ketones to corresponding chiral secondary alcohols. Products were obtained with high conversions (99%) and moderate to good enantioselectivities (82% ee). Furthermore, C2-symmetric bis(phosphinite) ligands and their binuclear ruthenium(II) complexes were characterized by multinuclear NMR spectroscopy, FT-IR spectroscopy, LC/MS-MS and elemental analysis. (C) 2017 Elsevier B.V. All rights reserved.Öğe Chiral phosphinites as efficient ligands for enantioselective Ru(II), Rh(I) and Ir(III)-catalyzed transfer hydrogenation reactions(Springer, 2017) Baysal, Akin; Karakas, Duygu Elma; Meric, Nermin; Ak, Bunyamin; Aydemir, Murat; Durap, FeyyazMetal-catalyzed enantioselective transfer reduction of ketones to enantiomerically enriched chiral alcohols has recently attracted attention. Therefore, a series of methyl alkyl or alkyl/aryl ketones have been reduced by using Ru(II), Rh(I) and Ir(III) catalysts based on C (2)-symmetric chiral ferrocenyl phosphinite ligands. The corresponding optically active secondary alcohols were obtained in excellent conversions and moderate-to-good enantioselectivities. The best results were obtained with an iridium catalyst, giving up to 98% conversion and 80% ee.Öğe Defatted spent coffee grounds-supported cobalt catalyst as a promising supercapacitor electrode for hydrogen production and energy storage(Springer, 2023) Karakas, Duygu Elma; Akdemir, Murat; Atelge, M. R.; Kaya, Mustafa; Atabani, A. E.The effect of several parameters, such as different Co2+ ratios, burning temperatures, and burning times, was examined by using defatted spent coffee grounds (DSCG) as organic waste to obtain the most effective catalyst for producing hydrogen. Under optimum conditions, the most active catalyst/metal ratio was obtained by burning 50% Co (2+) at 400 degrees C for 90 min. To measure the time-dependent amounts of hydrogen, 0.1 g of DSCG-Co catalyst was dissolved in 10 mL of a methanol solution containing 0.25 g sodium borohydride (NaBH4) at 30 degrees C. The maximum hydrogen generation rate obtained from the methanolysis of NaBH4 at 30 and 60 degrees C was found to be 8749 and 17,283 mL min(-1) gcat(-1), respectively, and the activation energy of the catalyst was found to be 23.2 kJ mol(-1). FTIR, ICP-OES, XRD, BET, and SEM-EDX analyses were performed for the characterization of the prepared DSCG-Co-Cat catalyst. Furthermore, a supercapacitor cell was constructed by using this catalyst as an active substance for electricity storage. The specific capacitance of the electrode at the current density of 1 A/g was calculated as 67 F/g for two-electrode systems. The results of electrochemical analysis of the prepared supercapacitor were found to be similar to the ideal supercapacitor curves. The obtained capacitance values are at very good levels in terms of the capacity and cost factors. The results indicated that the multifunctional capacitor-catalyst material produced by Co-doped waste coffee could constitute an important element in a hybrid system that includes capacitor and catalyst systems that can be installed in the future. [GRAPHICS] .Öğe Efficient hydrogen generation from the NaBH4 methanolysis by waste material: banana peel(Springer Japan Kk, 2022) Karakas, Duygu Elma; Kaya, Mustafa; Horoz, SabitThe aim and originality of our current study are to use the original biomass (activated carbon) obtained by functionalizing waste banana peels (commonly found in Turkey) with acid in NaBH4 methanolysis and to examine its contribution to the hydrogen generation rate (HGR). Our study consisted of three stages. In the first stage, the optimum conditions were determined by examining the catalyst under parameters such as different acid types, different carbonization temperatures, and different carbonization times. Thus, based on the maximum HGR value, the optimum conditions were determined as H3PO4, 600 degrees C, and 40 min. In the second step, the effects of parameters such as acid concentration, NaBH4 concentration, catalyst amount, and temperature on HGR were investigated. As a result of methanolysis experiments (condition: catalyst amount: 100 mg, acid amount: 30%, NaBH4 concentration: 2.5%, temperature: 30 degrees C, carbonization temperature: 400 degrees C, and carbonization time: 40 min.), the maximum HGR value, the reaction completion time and activation energy were found as 65,625 mLmin(-1)gcat(-1), 0.233 min, and 4.56 kJ/mol, respectively. It was observed that the obtained activation energy was lower than that of some catalysts available in the literature. In addition, the structural and morphological examination of the banana peel (catalyst) with high HGR and low activation energy revealed that the acid functionalization process was successfully carried out.Öğe Ferrocene based chiral binuclear ?6-benzene-Ru(II)-phosphinite complexes: Synthesis, characterization and catalytic activity in asymmetric reduction of ketones(Wiley, 2018) Al-bayati, Yaser W. Abdlhmed; Karakas, Duygu Elma; Meric, Nermin; Aydemir, Murat; Durap, Feyyaz; Baysal, AkinIn the present study, a series of chiral C-2-symmetric ferrocenyl based binuclear (6)-benzene-Ru(II) complexes bearing diphenylphosphinite and diisopropylphosphinite moieties have been synthesised. The new binuclear (6)-benzene-Ru(II)-phosphinite complexes were characterised based on nuclear magnetic resonance (H-1, C-13, P-31-NMR), FT-IR spectroscopy and elemental analysis. Then, these complexes have been screened as catalytic precursors in the transfer hydrogenation of acetophenone with 2-propanol as both the hydrogen source and solvent in the presence of KOH. The corresponding optically active secondary alcohols were obtained in excellent conversion rates between 96 and 99% and moderate to good enantioselectivities (up to 78% ee). The complex 5 was the most efficient catalyst among the four new complexes investigated herein.Öğe Integrated Catalytic and Energy Storage Performance of Grass Waste Derived Ni-Based Catalyst(Springer Heidelberg, 2024) Karakas, Duygu Elma; Horoz, Sabit; Durap, Feyyaz; Orak, Ceren; Kaya, MustafaThis study focuses on the optimization and characterization of a grass waste-derived catalyst, GW-Ni-Cat, for hydrogen generation via NaBH4 methanolysis, as well as its application in supercapacitors. Optimization experiments were conducted to determine the optimal conditions for acid concentration, metal concentration, carbonization temperature, and carbonization time. The catalyst was characterized using various techniques including FTIR, XRD, SEM, TEM, BET, and ICP-OES. Performance experiments demonstrated the catalyst's efficiency in hydrogen generation, with key factors such as catalyst amount, NaBH4 concentration, and temperature influencing the reaction kinetics. Reusability tests showed the catalyst's stability over multiple cycles. Electrochemical characterization revealed the suitability of GW-Ni-Cat as an electrode material for supercapacitors, with high specific capacitance values. Comparison with other bio-based supercapacitors demonstrated the superior performance of GW-Ni-Cat. Overall, this study presents GW-Ni-Cat as a versatile and efficient material for both hydrogen generation and energy storage applications.Öğe Nar kabuğu destekli NH2/PdMnAg katalizörü varlığında sodyum bor hidrürün metanolizinin araştırılması(2021) Karakas, Duygu ElmaBu çalışmada, organik atık kaynaklarından olan nar kabuğu, katalizör üretimi için ilk kez doğrudan destek malzemesi olarak kullanılmıştır. Amaç, yenilenebilir bir enerji kaynağı olan hidrojen üretimi için kullanılabilecek metal içeren katalizörlerde kullanılacak olan destek maddesini doğrudan kullanarak yüksek etkinliğe sahip bir katalizör sentezlemektir. Çalışma kapsamında toz haline getirilmiş nar kabuğu üzerine etanol eklenerek, daha sonra üzerine sırasıyla belirli oranlarda (0.3 Pd (mg metal/g katalizör)), (0.15 Mn ( mg metal/g katalizör)), (0.075 Ag ( mg metal/g katalizör)) ve 3-aminopropiltrimetoksisilan ilave edilerek katalizör sentezlenmiştir. Son olarak, elde edilen katalizör sodyum bor hidrürün metanoliz reaksiyonunda hidrojen üretiminde kullanılmak üzere performansı test edilmiştir. Yapılan deneylerde Nar Kabuğu-NH2/PdMnAg (PP-NH2/PdMnAg) katalizörünün farklı NaBH4 miktarı (%1, %2.5, %5, ve %7.5), farklı katalizör miktarları (0.05, 0.1, 0.15, ve 0.25 g) ve farklı sıcaklıklarda (30, 40, 50, 60 oC) denenerek performans deneyleri tamamlanmıştır. Ayrıca üretilen katalizörün karakterizasyonu için FTIR ve ICP-OES analizleri yapılmıştır. Sonuç olarak PP-NH2/PdMnAg katalizörü tarafından katalize edilen % 2.5 NaBH4 metanoliz reaksiyonunda 30 ve 60 °C için reaksiyon hızları sırasıyla 7209.4 ve 11334 mLdak-1g.kat-1 olarak bulunmuştur. PP-NH2/PdMnAg katalizörünün aktivasyon enerjisi ise 22,56 kJ mol-1 olarak hesaplanmıştır. Yeniden kullanılabilirlik deneyleri de aynı koşullar altında beş kez tekrarlanmış ve her kullanımda neredeyse % 100 dönüşüm elde edilmiştir.Öğe New bifunctional carbon material of metal-free pomegranate peel catalyst and supercapacitor for highly efficient hydrogen production and energy storage(Wiley, 2022) Karakas, Duygu ElmaIn this study, pomegranate peel (PP) waste was used as an efficient, cost-effective, and metal-free catalyst for the methanolysis reaction of sodium borohydride (NaBH4); furthermore, the prepared active material was utilized as a supercapacitor for electricity storage. The effect of several parameters, such as different acid concentrations, burning temperature, and burning times on the catalytic performance of the pomegranate peel catalyst (PP-H3PO4-Cat) were examined. Under optimum conditions, the most active catalyst was obtained by burning with 7 M phosphoric acid (H3PO4) solution at 400 degrees C for 45 minutes. The maximum hydrogen generation rate (HGR) obtained from the methanolysis reaction of NaBH4 at 30 degrees C and 60 degrees C was found as 57 200 and 76 228 mL min(-1) gcat(-1), respectively. The activation energy value for the catalytic methanolysis reaction was calculated as 7.89 kJ mol(-1). Furthermore, Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma - optical emission spectrometry (ICP-OES), X-ray diffractometer spectroscopy (XRD), Brunauer-Emmett-Teller (BET), and scanning electron microscope (SEM) analyses were performed for characterization of the synthesized catalyst. The gravimetric capacitance of the prepared electrode (catalyst material with best results) was calculated as 29 F/g at 0.25 A/g current density. The electrodes made from biomass waste are both cheap and have a good capacity.Öğe Novel ruthenium and palladium complexes as potential anticancer molecules on SCLC and NSCLC cell lines(Springer International Publishing Ag, 2020) Tokgun, Onur; Karakas, Duygu Elma; Tan, Semih; Karagur, Ege Riza; Inal, Behcet; Akca, Hakan; Durap, FeyyazLung cancer is one of the major causes of cancer-related deaths in the world. Non-small-cell lung cancer (NSCLC) is the most common type of lung cancer, and small-cell lung cancer (SCLC) is the most aggressive subtype of lung cancer. Proper therapies for SCLC have not yet been developed. However, new molecules have been designed and big innovation in treating SCLC has been achieved. Platinum-based antitumor drugs like cisplatin and carboplatin have several disadvantages including side effects, cisplatin-resistant tumors and limited solubility in aqueous media. Thus, two novel chiral aminoalcohol-based bis(phosphinite) ligands containing (eta(6)-p-cymene)-Ru(II)-phosphinite and bis(phosphinite)-Pd(II) complexes were synthesized and evaluated for anticancer activity. In this study, the results showed that complex1has the strongest cytotoxic effects on SCLC and NSCLC cell lines. On the other hand, cisplatin, ruthenium and palladium complexes are capable to induce apoptosis. Especially, complexes1and2can induce apoptosis for both SCLC and NSCLC. When compared to the qRT-PCR and TUNEL results, we obtained a significant correlation between apoptotic index and p21, Bax gene expressions. This work revealed the potential of the synthesized complexes as anticancer agents with cytotoxic and pro-apoptotic activity as leading compounds for further anticancer researches.Öğe Synthesis of a dual-functionalized carbon-based material as catalyst and supercapacitor for efficient hydrogen production and energy storage: Pd-supported pomegranate peel(Wiley, 2022) Akdemir, Murat; Karakas, Duygu Elma; Kaya, MustafaIn the current study, firstly, pomegranate peel (PP) was treated with phosphoric acid (H3PO4) and palladium chloride (PdCl2) solution. So, the PP-supported Pd (PP-H3PO4-Pd) catalyst was synthesized for hydrogen production by the methanolysis reaction. In this context, different burning temperatures (300 degrees C, 400 degrees C, 500 degrees C, and 600 degrees C), and burning times (30, 45, 60, and 90 minutes) were examined to test the activity of the PP-H3PO4-Pd catalyst by the methanolysis reactions. As a result of studies, the most active catalyst was obtained by burning 45 minutes at 300 degrees C (2 mL PdCl2 solution 2% w/w). The maximum hydrogen production rate (HPR) obtained at 60 degrees C by the methanolysis reaction was found as 37 240.4 mL min(-1) g cat(-1) and the activation energy was calculated to be 26.83 kJ mol(-1). Within the scope of this study, secondly, this PP-H3PO4-Pd catalyst was used as a supercapacitor active material for the first time to store electricity. Electrochemical characterization results were substantially similar to supercapacitor curves in the literature. At the current density of 1 A/g, the gravimetric capacitance of the prepared electrode was calculated as 84 F/g. Considering factors such as capacity, cost, and efficiency; the capacitance values of the produced ultracapacitor have a significant level.Öğe SYNTHESIS OF NOVEL BIS(PHOSPHINO)AMINE-RUII(ACAC)2 COMPLEXES, AND INVESTIGATION OF CATALYTIC ACTIVITY IN TRANSFER HYDROGENATION(2022) Karakas, Duygu Elma; Işık, Uğur; Aydemir, Murat; Durap, Feyyaz; Baysal, AkınIn this study, reactions of (PPh2)2NCH2CH2N(PPh2)2 (L1) and {(PPh2)2NCH2CH2}3N (L2) with [RuII(acac)2(CH3CN)2] led to the production of new dinuclear complex [Ru(acac)2]2(L1) (1) and trinuclear complex [Ru(acac)2]3(L2) (2). Complex 1 and 2 are excellent candidates for the role of catalyst precursors in the transfer hydrogenation (TH) of acetophenone and its derivatives. Compared to complex (1), the trinuclear complex (2) is an exceptional catalyst, producing the corresponding alcohols in 98–99% yields in 20 minutes at 80 oC (TOF?300 h-1 ) for the TH process. A comparison of the catalytic properties of the complexes is also briefly discussed. Complex structures have also been characterized by combining nuclear magnetic resonance (NMR), Fourier Transform Infrared (FT-IR), and elemental analysis.Öğe Synthesis, characterization and first application of chiral C2-symmetric bis(phosphinite)-Pd(II) complexes as catalysts in asymmetric intermolecular Heck reactions(Wiley-Blackwell, 2016) Karakas, Duygu Elma; Durap, Feyyaz; Aydemir, Murat; Baysal, AkinA series of new chiral C-2-symmetric bis(phosphinite) ligands and their palladium(II) complexes have been synthesized and for the first time used as catalysts in the palladium-catalysed asymmetric intermolecular Heck coupling reactions of 2,3-dihydrofuran with iodobenzene or aryl triflate. Under optimized conditions, products were obtained with high conversions and moderate to good enantioselectivities. The new C-2-symmetric bis(phosphinite) ligands and their palladium(II) complexes were characterized using multinuclear NMR and Fourier transform infrared spectroscopies and elemental analysis. Copyright (c) 2015 John Wiley & Sons, Ltd.Öğe The dual functionality of Zn@BP catalyst: methanolysis and supercapatior(Springer, 2022) Karakas, Duygu Elma; Akdemir, Murat; Kaya, Mustafa; Horoz, Sabit; Yasar, FevziIn the present study, activated carbon is synthesized by combining banana peel (BP) and ZnCl2 at high temperature for the first time, and the existing catalyst (Zn@BP) is used as a dual function both in hydrogen production and in supercapacitor application. In methanolysis experiments, optimum conditions are determined based on the maximum hydrogen generation rate (HGR). Methanolysis experiments are performed in the presence of different parameters, such as different H3PO4 concentrations, different ZnCl2 concentrations, different carbonization temperatures, and different carbonization times. Thus, in the presence of Zn@BP catalyst, the maximum HGR value is recorded as 43,665 mLmin(-1)gcat(-1) (Experimental conditions: catalyst amount: 100 mg, NaBH4 concentration: 2.5%, temperature: 30 degrees C, H3PO4 concentration: 40%, ZnCl2 concentration: 30%, carbonization temperature: 700 degrees C, and carbonization time: 40 min.). Zn@BP catalyst with maximum HGR value is used as an electrode in supercapacitor applications. The specific capacitance value of the electrode is determined as 223.98 F/g for 1 A/g. Furthermore, the Zn@BP catalyst is characterized structurally and morphologically.Öğe The effects of plasma treatment on electrochemical activity of Co-B-P catalyst for hydrogen production by hydrolysis of NaBH4(Elsevier Sci Ltd, 2017) Sahin, Omer; Karakas, Duygu Elma; Kaya, Mustafa; Saka, CaferIn this paper, the hydrogen generation from the hydrolysis of NaBH4 with plasma treated Co-B-P catalyst are investigated as based on NaBH4 concentration, NaOH concentration, temperature, plasma applying time and plasma gases. The changes in surface chemistry and morphology induced by the plasma treatment are examined using scanning electron microscopy (SEM), N-2 adsorption-desorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The hydrogen generation rate from hydrolysis of NaBH4 with Co-B-P prepared in the presence of plasma is completed in 12 min time intervals that exhibited a higher hydrogen generation rate of 60%, while the Co-B-P produced in known method let to slower hydrogen release, and the hydrolysis is completed in 30 min time intervals. The maximum hydrogen generation rates of the plasma treated and plasma untreated Co-B-P catalysts toward NaBH4 hydrolysis are 3976 and 1807 mL/g/min, respectively. The activation energy for zero-order is found to be 49.11 kJ mol(-1). (C) 2016 Energy Institute. Published by Elsevier Ltd. All rights reserved.
