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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.
An efficient synergistic Co@CQDs catalyst for hydrogen production from the hydrolysis of NH3BH3
(Springer, 2021) Onat, Erhan; Sahin, Omer; Izgi, Mehmet Sait; Horoz, Sabit
We report the synthesis of carbon quantum dots supported-Co (Co@CQDs) catalyst and its catalytic activity. The synthesized Co@CQDs catalyst for the first time is used to obtain the maximum hydrogen production rate from hydrolysis of NH3BH3. The synthesized Co@CQDs catalyst indicates a compelling performance in the hydrogen production from the hydrolysis of NH3BH3. It is found that Co@CQDs with the loading of Co (10 wt%) indicates a hydrogen production rate of 18600.27 mL/min.g(cat) and low activation energy of 22.97 kJ mol(- 1). The current study demonstrates that CQDs are promising support for dispersing metal catalysts. Moreover, the synthesized Co@CQDs catalyst is characterized by X-ray diffraction, ultraviolet and visible light, photoluminescence, inductively coupled plasma optical emission spectrometry, and transmission electron microscope measurements.
An Investigation of the Effect of CuMoB Nanocatalysts on Efficient Hydrogen Production
(Pleiades Publishing Inc, 2022) Demirci, Sevilay; Izgi, Mehmet Sait; Bestas, Hatice; Sahin, Omer
In this study, the Cu-Mo-B catalyst in nanostructure was successfully synthesized with the chemical reduction method of sodium borohydride (NaBH4). The categorization of the attained Cu-Mo-B nano-catalyst was examined with XRD, BET, SEM, and EDS analytical methods. As a result of the ammonium borane hydrolysis of this attained catalyst, the most convenient Mo/Co ratio, NaOH impact, the impact of different catalyst amounts, and the impact of different ammonium borane concentrations on ammonium boron hydride hydrolysis were examined. In addition, hydrolysis was examined at different temperatures, and the degree and activation energy of the reaction were determined. At 333 K with the ammonium borane (AB) hydrolysis of Cu-Mo-B nanoparticles, the maximum hydrogen production rate and activation energy were found to be 4075 mL min(-1)g(cat)(-1) and 21.37 kJ mol(-1), respectively. In this context, Cu-Mo-B catalyst can be used in practical fuel cells since it is obtained economically and easily.
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-B 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.
Computational study on a cobalt-based complex compound with amine ligand in X-doped (X = Co, Ru, Rh) Ca12Al14O33 functional material as an innovative catalyst by NaBH4 hydrolysis for determining hydrogen generation process
(Pergamon-Elsevier Science Ltd, 2024) Celik, Fatih Ahmet; Karabulut, Ezman; Izgi, Mehmet Sait; Yilmaz, Mucahit; Onat, Erhan
Sodium borohydride (NaBH4) has been generally studied as a source of hydrogen (H2) due to its important advantages with the development of support materials and catalysts for H2 release in the energy sector. In this context, we carry out molecular dynamics (MD) simulations by using extended tight-binding (xTB) model Hamiltonian based on density functional theory (DFT) and analyze the Ca12Al14O33 functional material doped X metals (X = Co, Ru, Rh) as a catalyst with [Co(III)(N3)3(C9H8N2)2] as complex compound with amine ligand from NaBH4 hydrolysis for H2 production. The use of a functional material doped by X metals causes to the high rate in H2 production when compared to without functional material doped by X metals. The increase of complex compound with amine ligand facilitates H2 production. Rh on the functional material displays the best catalytic performance compared to Ru and Co to increase the H2 production rate. Also, the increment of temperature has a positive effect on the H2 production rate with functional material doped Co, Ru and Rh metals. Thus, Ca12Al14O33 support material doped with noble metals appears promising as an innovative catalyst for H2 production.
Effect of microwave irritated Co-B-Cr catalyst on the hydrolysis of sodium borohydride
(Taylor & Francis Inc, 2016) Izgi, Mehmet Sait
In this work, Co-B-Cr catalysts were synthesized from CoCl2.6H(2)O and Cr(NO3)(2) 9H(2)O compounds by using NaBH4 as chemical reducing agent at temperature range of 5-8 degrees C. The microwave irradiation method utilized depends on different gas medium (N-2, Ar, CO2), microwave power (0-1,000 W), and microwave applying time (0-20 min) to increase the catalytic activity of Co-B-Cr catalysis used in the hydrolysis of NaBH4. It was found that the Co-B-Cr catalyst with best catalytic activity for NaBH4 hydrolysis was produced under microwave conditions of N-2 gases for 15 min treatment time and 500 W applying power. Hydrolysis of NaBH4 is completed in 500 s by using Co-B-Cr catalysis treatment optimum irradiation microwave conditions and it is completed in 1,200 s in the case of non-microwave treatment of Co-B-Cr catalyst. The effect of microwave irradiation on Co-B-Cr surface was investigated by using scanning electron microscopy analysis.
Effect of plasma pretreatment of Co-Cu-B 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)).
Epoxy-activated acrylic particulate polymer-supported Co-Fe-Ru-B catalyst to produce H2 from hydrolysis of NH3BH3
(Pergamon-Elsevier Science Ltd, 2020) Izgi, Mehmet Sait; Sahin, Omer; Onat, Erhan; Saka, Cafer
Epoxy-activated acrylic particulate polymer, namely Eupergit CM, supported Co-Fe-Ru-B catalyst (EP/Co-Fe-Ru-B) for the first time was used to produce H-2 from hydrolysis of NH3BH3. The EP/Co-Fe-Ru-B showed very effective performance in the production of H-2 from the hydrolysis of NH3BH3. Various techniques such as XRD, SEM-EDS, ICP-OES, and TEM have been used to characterize these catalysts. The parameters on the hydrolysis reaction of NH3BH3 such as the effect of metal amount, the effect of Ru percentage, the effect of NH3BH3 concentration, the effect of NaOH concentration, the amount of catalyst, temperature, and catalyst durability were investigated in detail. Eupergit CM based poly-mer support and Ru particles have been found to be highly effective in H-2 production re-actions. The hydrogen production rate (HGR) of the EP/Co-Fe-Ru-B catalyst was found to be 36,978 mL/min/g(cat), which was quite good compared to the values reported in the literature. In addition, the activation energy (Ea) of the polymer-supported Co-Fe-Ru-B catalyst was determined as 24.91 kJ/mol. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Green and active hydrogen production from hydrolysis of ammonia borane by using caffeine carbon quantum dot-supported ruthenium catalyst in methanol solvent by hydrothermal treatment
(Pergamon-Elsevier Science Ltd, 2024) Izgi, Mehmet Sait; Onat, Erhan; Sahin, Omer; Saka, Cafer
Here, carbon quantum dot (CQD) supported Ru nanoparticles from the caffeine in methanol or water by the hydrothermal method were synthesized for the first time to produce hydrogen (H-2) by hydrolysis of ammonia borane(NH3BH3) and their catalytic activities were investigated. The chemical compositions and morphology structures of this caffeine carbon dot-supported Ru catalysts were carefully characterized by UV, PL, TEM, FTIR, and ICP/OES analyses. Well-dispersed Ru nanoclusters with similar to 1.81 nm particle size on CQD by the hydrothermal method in methanol medium showed very good catalytic performance. The turnover frequency (TOF) obtained for H-2 production from the catalytic hydrolysis of 5% NH3BH3 with CQD supported Ru catalyst obtained by the hydrothermal method in methanol and water was found to be 361 and 1895 mol H-2 min(-1) mol(-1), respectively. The activation energies (Ea) for NH3BH3 hydrolysis with the same catalysts were measured as 33.32 and 27.80 kJmol(-1), respectively.
H2 2 production from ammonia borane hydrolysis with catalyst effect of Titriplex® ® III carbon quantum dots supported by ruthenium under different reactant Conditions: Experimental study and predictions with molecular modelling
(Elsevier Science Sa, 2024) Onat, Erhan; Celik, Fatih Ahmet; Sahin, Omer; Karabulut, Ezman; Izgi, Mehmet Sait
This study presents experimental and theoretical results on the role of the catalytic effect by ruthenium added titriplex (R) (R) III Carbon Quantum Dots (CQD) support material in the hydrolysis of ammonia borane for H2 2 duction. H2 2 production was achieved under different reactant conditions (in variable amounts of catalysis, ruthenium, NaOH, ammonia borane and at various temperature). Since the experimental results and theoretical calculations which includes the effect of all electrical forces acting on valence electrons (overlap density tions, van der Waals forces, Covalent bonding and halogen bonds) are in very good agreement in the study, theoretical predictions are also made. By considering the rhodium element instead of the ruthenium element, performance of the titriplex support material was estimated to be approximately 30% more effective ruthenium. The NaOH molecule acts as a hydrolyzed water molecule with catalysis interaction and contributes the formation of oxidized boron. When NaOH is not present, the interaction time of the ammonia borane molecule with catalysis comes to the fore. This time is called threshold time. In molecular modeling, while almost all of the ammonia borane molecules contribute to H production, only 15% of the water molecules contribute this rate. However, while some of the released H atoms remains in the water, other parts observe to play a role the production of H2 2 and hydronium. The interaction rate of the water molecule increases with the increase the interaction surface of the catalyst. Any external effect that prevents the formation of hydronium and celerates the interaction of free H atoms with each other increases the efficiency. One of the predicted results this study is that the increased pressure shows separating role for hydronium.
High availability and outstanding catalytic activity in sodium borohydride hydrolytic dehydrogenation of CQD/GO@Co catalyst by green synthesis: Experimental and computational perspective
(Pergamon-Elsevier Science Ltd, 2024) Onat, Erhan; Celik, Fatih Ahmet; Karabulut, Ezman; Izgi, Mehmet Sait
This study is a pioneering study that experimentally and theoretically measures the effect of heterogeneous catalyst structure on hydrogen production. In this research, the catalytic activity of the (CQD/GO@Co) catalyst, which was formed by doping Co onto the synthesized graphene oxide (GO) on carbon quantum dots (CQD) obtained from caffeine by green synthesis, was investigated. The catalyst CQD/GO@Co was synthesized with high dispersibility and activity, and it was successfully employed in the hydrolysis of NaBH4 for the first time. The effective catalytic compatibility of caffeine and cobalt element increased approximately 3 times on the GO layer. In order to determine the most effective catalyst conditions in the study, NaOH concentration, catalyst amount, NaBH4 amount and temperature were tested under different reactant conditions. The catalyst was characterized using X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) analyses. Field emission scanning electron micrographs (FESEM) were taken by Field emission scanning electron microscope (Zeiss, Sigma). Energy dispersive X-ray (EDX) spectra were obtained from Energy dispersive X-ray spectroscope. According to spherical aberration transmission electron microscopy studies, the uniform dispersion of Co nanoparticles (average diameter: +/- 3,1 nm) on CQDs, as well as the very small size and good dispersion of Cobalt (Co), are conducive to improved catalytic performance. This situation was determined by molecular modeling with the Non-scc GFN1xTB model and results supporting the experimental data were obtained. The maximum hydrogen production rate with sodium borohydride hydrolysis using cobalt-based catalyst increased approximately 32 times (from metallic crystal form of Co catalyst 2860 mL/min.(g.cat) to the present form 49,044 mL/min.(g.cat). The activation energy, activation enthalpy, and activation entropy of the Co@CQDs catalyst were founded to be 20.65 kJ mol(-1), 2.64 kJ mol(-1), and -108,97 J mol(-1), respectively.
Highly active hydrogen production from hydrolysis of potassium borohydride by caffeine carbon quantum dot-supported cobalt catalyst in ethanol solvent by hydrothermal treatment
(Pergamon-Elsevier Science Ltd, 2024) Onat, Erhan; Izgi, Mehmet Sait; Sahin, Omer; Saka, Cafer
Herein, the efficiency of the Co catalyst synthesized in caffeine-based carbon quantum dot- supported material using ethanol solvent was evaluated for H2 production from the hy- drolysis of KBH4. The chemical compositions and morphology structures of these caffeine carbon dot-supported Co catalysts were carefully characterized by XRD, TEM, BET, EDS, FTIR, XPS, and ICP/OES analyses. XPS, FTIR and EDX analyses showed abundant oxygen atoms on the caffeine carbon dot-supported Co catalyst. It can be attributed to the prevention of aggregation of particles by reducing the average particle size with both caffeine and carbon quantum dots materials. The catalysts prepared in methanol and ethanol solvent by hydrothermal treatment compared to water have significant effects on H2 production from KBH4 hydrolysis. The H2 production rate obtained by Co@MOF-CQD (ethanol) at 30 degrees C was 17,081 ml min-1g-1. At the same time, the TOF value obtained with 4% KBH4 for the Co@MOF-CQD (ethanol) was found as 2765 h-1. The reusability of Co@CQD-MOF(ethanol) for the catalytic hydrolysis of KBH4 for H2 production was evaluated by six consecutive experiments.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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 mechanism and catalytic productivity of Ni-X@g-C3N4 (X = precious and non-precious promoter metals) catalysts from KBH4 hydrolysis under stress loading and atmospheric pressure: Experimental analysis and molecular dynamics approach
(Elsevier Science Sa, 2024) Celik, Fatih Ahmet; Aygun, Murat; Karabulut, Ezman; Onat, Erhan; Izgi, Mehmet Sait; Yilmaz, Muecahit; Ayguen, Zeynep
In this study, the pressure effect of Ni-based catalysts added a second promoter metal to increase of catalyst performance supported a graphite carbon nitride (g-C3N4) monolayer on hydrogen release mechanisms from potassium boron hydride (KBH4) hydrolysis was investigated using molecular dynamics (MD) method based on tight-binding density functional theory (DFT). The use of the various promoters, such as transition metals (X = Cu, Ta and W) and noble metals (X = Pd, Pt and Rh) with applying a high external pressure was investigated to understand the role on catalytic performance of the Ni-based catalysts under stress loading. The g-C3N4 monolayer doped with Ni-X nano-catalysts was used for efficient H-2 release from KBH4 hydrolysis. The computational results show that the number of H-2 shows more increment with MD time for NiW and NiRh catalysts than other NiTa and NiCu (transition metals) and NiPd and NiPt (noble metals) under 0 GPa pressure. On the other hand, a notable increase in H-2 amount is seen only NiCu and NiRh catalysts under 50 GPa. Also, the mechanism of the H-2 production reaction from KBH4 hydrolysis of g-C3N4 doped NiCo catalysts was clarified. High-performance cost metal catalysts such as NiCo was investigated as both experimentally and modeling under atmospheric pressure to enhance its commercial application value. Some experimental applications and analyzes were also performed to measure the accuracy of the modeling for the relevant molecular groups in the system.
Investigation of high catalytic activity catalyst for high hydrogen production rate: Co-Ru@MOF
(Springer, 2021) Onat, Erhan; Cevik, Sabri; Sahin, Omer; Horoz, Sabit; Izgi, Mehmet Sait
We report the synthesis of metal-organic framework supported-Co-Ru (Co-Ru@MOF) catalyst and its catalytic activity. The synthesized Co-Ru@MOF catalyst for the first time is used to obtain the maximum hydrogen production rate from hydrolysis of NaBH4. The synthesized Co-Ru@MOF catalyst indicates a compelling performance in the hydrogen production from the hydrolysis of NaBH4. It is found that Co-Ru@MOF with the loading of Co (80 wt%) and Ru (20 wt%) indicates a high hydrogen production rate of 15,144 mL/min.g and low activation energy of 41.41 kJ mol(-1). The current study demonstrates that MOF is promising support for dispersing metal catalysts. Moreover, the synthesized Co-Ru@MOF catalyst is characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersion spectroscopy (EDS) measurements.
Microwave treatment and fluorine addition on Co-B catalyst to improve the hydrogen production rate
(Taylor & Francis Inc, 2018) Izgi, Mehmet Sait; Sahin, Omer; Odemis, Omer; Saka, Cafer
In this paper, microwave heating treatment process and fluorine addition over Co-B-F catalyst was applied to produce hydrogen via the hydrolysis of NaBH4. The effects of microwave heating treatment time, microwave heating treatment power, microwave inert gases and temperature on the catalyst were studied. X-ray absorption spectrometer, scanning electron microscopy coupled to energy-dispersive spectroscopy, nitrogen adsorption analyzer and infrared spectrometer were performed for the chemical characterization of the catalysts. It was found that Co-B-F and microwave-treated Co-B-F catalysts exhibited excellent catalytic activity to produce hydrogen. The rates of the maximum hydrogen production for untreated and microwave-treated Co-B-F catalysts are 1868 and 3400 mL/g/min, respectively.
Molecular dynamics approach to efficient hydrogen generation process of Co-B catalysts decorating lanthanides (La, Ce, Pr, Nd) supported by flat-sheet and twisted ThMoB4-type graphene from NaBH4 hydrolysis: Insights from non-self-consistent GFN1-xTB method
(Elsevier Science Sa, 2024) Celik, Fatih Ahmet; Karabulut, Ezman; Onat, Erhan; Izgi, Mehmet Sait; Yilmaz, Mucahit
In this study, the promoter role on highly efficient hydrogen generation productivity and H-2 formation mechanisms of Co-B-X catalysts modified by rare earths (X = La, Ce, Pr, Nd) supported by flat-sheet and twisted ThMoB4-type graphene from sodium borohydride (NaBH4) hydrolysis was investigated using molecular dynamics (MD) method based on non-self-consistent tight binding GFN1-xTB Method. The twisted ThMoB4-type graphene layer was constructed by adsorbing of ethylene carbonate (EC) molecule on armchair site of graphene surface with applying of geometric optimization process. The addition of Nd to CoB exhibited to higher H-2 release compared to other CoB containing lanthanides (La, Ce and Pr) both flat-sheet and twisted ThMoB4-type graphene. While the number of H-2 for Co-B-Nd is 14, the H-2 amount is only 8 for Co-B-Ce supported flat-sheet graphene at the end of simulation time. Also, the placing of twisted graphene instead of flat-sheet in the catalytic complex led to about 36 % increase in H-2 number for Co-B-Nd. The computational results revealed that the availability of the active sites, such as basicity of catalytic environment related to OH and H species and the mobility of Co atom, played an important role for catalytic activity and performance for H-2 production. This work can provide new insight for experimental studies of Co-B-X (X = La, Ce, Pr, Nd) catalysts for hydrogen production in atomic-level and the creation of new hydrogen energy applications and facilitates for H-2 generation efficiency.
Nickel/nickel oxide nanocomposite particles dispersed on carbon quantum dot from caffeine for hydrogen release by sodium borohydride hydrolysis: Performance and mechanism
(Elsevier Science Sa, 2024) Onat, Erhan; Izgi, Mehmet Sait; Sahin, Omer; Saka, Cafer
The political and economic problems caused by the limited use of fossil fuels are another important reason that leads people to alternative energy sources. Compared to other energy sources, hydrogen has the potential to be the energy source of the future. In this study, the preparation of Ni/NiO doped caffeine-based carbon dot(CCQD) for efficient hydrogen (H2) production from the hydrolysis of sodium borohydride (NaBH4) is included the fabrication of nanoscale caffeine-based carbon quantum dot, the preparation of the CCQD-supported Ni/NiO catalyst as boron-free and the preparation of the CCQD-supported Ni/NiO catalyst by hydrothermal treatment in ethanol solvent (NiO@ CCQD-HT (EtOH)). The HGR values obtained with NiO@CCQD-HT (EtOH) was 16,819 ml min- 1gcat- 1. Moreover, the turnover frequency (TOF) value for the NiO@CCQD-HT (EtOH) was found as 2315 h-1. The activation energy (Ea) for the NiO@CCQD-HT (EtOH) catalyst was 39.48 kJmol-1.
Revolutionary carbon quantum dot supported-Co catalyst for record-breaking hydrogen production rate
(Springer, 2024) Onat, Erhan; Horoz, Sabit; Sahin, Omer; Izgi, Mehmet Sait
In this study, we introduce a groundbreaking approach in the field of hydrogen production by synthesizing and characterizing a carbon quantum dot supported-Co (Co-B_CQDs) catalyst. Our results demonstrate that this state-of-the-art catalyst exhibits exceptional performance in the hydrolysis of KBH4, resulting in a record-breaking hydrogen production rate of 23,019.97 mL*gcat(-1)*min(-1) and a remarkably low activation energy of 19.36 kJ/mol. This is the first time that this type of catalyst has been used to achieve such outstanding results. The study highlights the remarkable potential of carbon quantum dots as a support material for dispersing metal catalysts, which opens up new avenues for research in the field of hydrogen production. The synthesized catalyst was extensively characterized using various analytical techniques such as X-ray diffraction (XRD), ultraviolet and visible light (UV-Vis), photoluminescence (PL), and inductively coupled plasma optical emission spectrometry (ICP-OES) measurements, which further confirmed its superior performance.

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