共查询到20条相似文献,搜索用时 11 毫秒
1.
《International Journal of Hydrogen Energy》2020,45(16):9845-9853
Developing non-precious metal catalysts with high activity is crucial for the extensive applications of the proton exchange membrane fuel cell (PEMFC). Herein, we have prepared cobalt–copper–boron (Co–Cu–B) nanoparticles by a modified chemical reduction route where Ni foam was used as an initiation medium for the efficient hydrolysis of alkaline sodium borohydride (NaBH4) solution. The influence of the synthetic condition (such as Cu2+ concentration, pH value and the concentration of reducing agent) on the catalytic activities has been explored. The catalytic hydrolytic tests reveal that the as-obtained Co–Cu–B nanoparticles with hollow spherical structure shows highly efficient catalytic activity, affording a hydrogen generation rate (HGR) of 3554.2 under room temperature, and a lower activation energy of 52.0 kJ· mol−1, which overtakes the activities of previous reported most non-precious metal catalysts, even some precious catalysts. The kinetics results show that the catalytic hydrolysis process of alkaline NaBH4 solution is a zero-order reaction in view of the amount of Co–Cu–B catalyst, meaning that the reaction rate is independent of the catalyst amount. This study offers us a promising non-precious metal catalyst toward dehydrogenation from the hydrolysis of NaBH4 to further speed up the application steps. 相似文献
2.
《International Journal of Hydrogen Energy》2023,48(60):23055-23066
In this study, nickel, nickel-chromium alloy, and nickel-vanadium alloy were coated to form a thin film on the slides prepared by magnetron sputtering process, which were used as a catalyst for the hydrolysis of alkaline sodium borohydride. Factors, such as the temperature of the solution, amount of the catalyst, initial pH of the solution and the performance of these catalysts on hydrogen generation rate were investigated using response surface methodology. Moreover, the catalysts were characterized using XRD and FE-SEM/EDS analyses. Utilizing the obtained optimum conditions of the response surface methodology estimation, the maximum hydrogen generation rate was 35,071 mL min−1 gNiV−1 from NiV catalyst at 60 °C, pH 6, and 1.75 g catalyst conditions. Under the same experiment conditions, the maximum hydrogen generation rates of Ni and NiCr catalyst systems are 28,362 mL min−1 gNi−1, and 30,608 mL min−1 gNiCr−1, respectively. 相似文献
3.
Joshua C. Walter Andrew ZurawskiDaniel Montgomery Matt ThornburgShripad Revankar 《Journal of power sources》2008
Hydrolysis tests have been performed at a constant temperature of 60 °C over a range of sodium borohydride (2.5–30 wt%) and sodium hydroxide (2.5–30 wt%) concentrations. Catalysts used to initiate the hydrolysis reaction were developed through the metal salt reduction method with sodium borohydride. These catalysts were identified as nickel boride, cobalt boride, and ruthenium with each catalyst having similar morphology. Catalysts were tested in loose, powder form free of binders or substrates. Hydrolysis rate comparisons show that reaction rates decrease linearly with increasing NaBH4 concentrations due to mass transfer limitations. Increasing NaOH concentration has been shown to drive a non-catalyzed intermediate reaction with the rate of the overall reaction hindered by the catalysts’ ability to bind hydrogen to active sites. Maximum hydrogen production rates for the Ni3B, Co3B, and Ru catalysts were found to be 1.3, 6.0, and 18.6 L min−1 gcat−1, respectively. 相似文献
4.
Hitoshi Inokawa Hafedh Driss Florencio Trovela Hiroki Miyaoka Takayuki Ichikawa Yoshitsugu Kojima Sharif F. Zaman Abdulrahim Al‐Zahrani Yahia Alhamed Lachezar Petrov 《国际能源研究杂志》2016,40(15):2078-2090
The addition of NaBH4 to Co–ethylenediaminetetraacetate (Co–EDTA) and Co–citrate solutions at 25 °C does not lead to generation of hydrogen. However, in the presence of Co‐based catalysts synthesized via chemical reduction of Co–EDTA and Co–citrate complexes with NaBH4 at elevated temperature, an intensive generation of H2 took place. In this study, the reduction mechanism of both complexes was elucidated by using various techniques. From the results of attenuated total reflection and mass spectrometry analysis, it was suggested that NaBH4 was oxidized to NaBO2 and that organic ligands of Co complexes were decomposed to gaseous hydrocarbons, such as C2H4, C3H4, and/or C2H3N. Structural characterizations of X‐ray diffraction, scanning transmission electron microscopy, transmission electron microscope, energy‐dispersive spectroscopy, and X‐ray photoelectron spectra on the catalysts revealed that Co(OH)2, metallic cobalt, and cobalt borate were obtained in both cases. The morphology of Co(OH)2 and the dispersion of metallic cobalt and cobalt borate nanoparticles were significantly different. In the case of the catalyst prepared from Co–EDTA, the nanoparticles of Co species aggregated with diameters from 100 to several hundred nanometers on Co(OH)2 slabs. On the catalyst prepared from Co–citrate, the Co(OH)2 formed sheets, and the nanoparticles of Co species formed clusters of 5–10 nm in diameter, which are dispersed well on the Co(OH)2 sheet. The catalyst obtained from Co–citrate showed higher catalytic activity on hydrolysis reaction of NaBH4 than that from Co–EDTA. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
Dilek Kılınç Ömer Şahin Cafer Saka 《International Journal of Hydrogen Energy》2017,42(32):20625-20637
In this study, 5-amino-2, 4-dichlorophenol-3, 5-ditertbutylsalisylaldimine-Ni complex catalyst is synthesised and used as an alternative to previous studies to produce hydrogen from hydrolysis of sodium borohydride. The resulting complex catalyst is characterised by XRD, XPS, SEM, FT-IR and BET surface area analyses. Experimental works are carried out at 30 °C with 2% NaBH4, 7% NaOH and 5 mg of catalyst. The maximum hydrogen production rate from hydrolysis of sodium borohydride with nickel-based complex catalyst compared to the pure nickel catalyst is increased from 772 ml min?1g?1 to 2240 ml min?1g?1 by an increase of 190%. At the same time, the hydrolysis reaction with pure nickel catalyst is completed in 145 min while the hydrolysis reaction with nickel-based complex catalyst is completed in 50 min. The activation energy of this hydrolysis reaction was calculated as 18.16 kJ mol?1. This work also includes kinetic information for the hydrolysis of NaBH4.The reusability of the nickel-based complex catalyst used in this study has also been studied. The nickel-based complex catalyst is maintained the activity of 72% after the sixth use, compared to the first catalytic use. 相似文献
6.
Aybike Paksoy Samira Fatma Kurtoğlu Azam Khodadadi Dizaji Zerrin Altıntaş Sina Khoshsima Alper Uzun Özge Balcı 《International Journal of Hydrogen Energy》2021,46(11):7974-7988
Innovative metal boride nanocatalysts containing crystalline Co–Ni based binary/ternary boride phases were synthesized and used in the hydrolysis of NaBH4. All the as-prepared catalysts were in high-purity with average particle sizes ranging between ~51 and 94 nm and consisting of different crystalline phases (e.g. CoB, Co2B, Co5B16, NiB, Ni4B3, Ni2Co0·67B0.33). The synergetic effect of the different binary/ternary boride phases in the composite catalysts had a positive role on the catalytic performances thus, while the binary boride containing phases of unstable cobalt borides or single Ni4B3 were not showing any catalytic activity. The Co–Ni–B based catalyst containing crystalline phases of CoB–Ni4B3 exhibited the highest H2 production rate (500.0 mL H2 min?1 gcat?1), with an apparent activation energy of 32.7 kJ/mol. The recyclability evaluations showed that the catalyst provides stability even after the 5th cycle. The results suggested that the composite structures demonstrate favorable catalytic properties compared to those of their single components and they can be used as alternative and stable catalysts for efficient hydrogen production from sodium borohydride. 相似文献
7.
8.
《International Journal of Hydrogen Energy》2019,44(27):14207-14216
Nickel complexes have recently been presented as prospective catalytic materials for hydrogen H2 evolution by hydrolysis of sodium borohydride NaBH4. An attractive complex is nickel hydrazine nitrate [Ni(N2H4)3][NO3]2 for which little variations in the synthesis procedure result in different morphologies like hexagonal plates, clews and discs. In our conditions, the clews have the better catalytic activity owing to more defects and more active sites. There is an effect of the morphology on the catalytic activity. However, the H2 evolution curves (regardless the initial morphology) show an induction period during which the complex (purple violet in color) evolves into a catalytically active form (fine black powder). The evolution is featured by changes in morphology and chemical state of nickel. The catalytically active form is even more active than the pristine complex: it shows a higher H2 generation rate (three times higher in the best case). The starting complexes and the “reduced” counterparts have been then characterized (e.g. SEM, FTIR, XRD, XPS) to better understand the aforementioned evolutions. One of our main conclusions is that there are some marked analogies between our nickel-based catalysts and the much-investigated cobalt-based catalysts. 相似文献
9.
Herein we report for the first time the preparation and catalytic use of the ceria supported manganese(0) nanoparticles in hydrogen generation from the hydrolysis of sodium borohydride. They are in situ formed from the reduction of manganese(II) ions on the surface of ceria nanopowders during the catalytic hydrolysis of sodium borohydride in aqueous solution at room temperature. Manganese(0) nanoparticles are isolated from the reaction solution by centrifugation and characterized by a combination of analytical techniques. Nanoceria supported manganese(0) nanoparticles are highly active and long-lived catalysts providing a turnover frequency of 417 h?1 and 45,000 turnovers in hydrogen generation from the hydrolysis of sodium borohydride at 25.0 ± 0.1 °C. They also have high durability as they retain 55% of their initial catalytic activity after the fifth cycle of hydrolysis providing a release of 4 equivalent H2 gas per mol of sodium borohydride. The noticeable activity loss in successive runs of hydrolysis is attributed to the deactivation due to agglomeration. High activity and stability of ceria supported manganese(0) nanoparticles are ascribed to the unique nature of reducible cerium oxide. The formation of cerium(III) defects under catalytic conditions provides strong binding for the manganese(0) nanoparticles to oxide surface which makes the catalytic activity and stability favorable. Our report also includes the results of kinetic study of catalytic hydrolysis of sodium borohydride depending on the temperature, catalyst and substrate concentration. 相似文献
10.
11.
《International Journal of Hydrogen Energy》2021,46(64):32403-32412
Porous carbon nanostructures are promising supports for stabilizing the highly dispersed metal nanoparticles and facilitating the mass transfer during the reaction, which are critical to achieve the high efficiency of hydrogen generation from sodium borohydride dehydrogenation. Herein, the catalytically active porous architectures are simply prepared by using 2-methylimidazole and melamine as reactive sources. The structural and compositional characterizations reveal the coexistence of metallic cobalt and N-doped carbon in porous architectures. Electron microscopy observations indicate that the synthesized products are smartly constructed from the carbon nanosheets with densely dispersed Co nanoparticles. Due to the notable structural features, the prepared Co@NC-600 sample presents the highly efficient activity for catalytic hydrolysis of NaBH4 with a hydrogen generation rate of 2574 mL min−1 gcat−1 and an activation energy of 47.6 kJ mol−1. The catalytically active metallic Co and suitable support-effect of N-doped carbon are responsible for catalytic dehydrogenation. 相似文献
12.
《International Journal of Hydrogen Energy》2020,45(58):33288-33309
Sodium borohydride constitutes a safe alternative for the storage of hydrogen with a high gravimetric content. Catalytic hydrolysis of sodium borohydride permits on-demand hydrogen generation for multiple applications. In this field, the rational design of efficient metal catalysts deposited on structured supports is highly desirable. For most reactions, chemical methods are the most commonly used methods for the preparation of supported metal catalysts. Physical vapour deposition techniques are emerging as an alternative for the preparation of catalytic materials because of their multiple advantages. They permit the one-step deposition of catalysts on structured supports with controlled microstructure and composition, avoiding the multi-step procedures and the generation of hazardous by-products associated with chemical routes.In this short review, we will describe the available literature on the application of physical vapour deposition techniques for the preparation of supported metal catalysts for the hydrolysis of sodium borohydride. The effects of the deposition parameters on the properties of the catalytic materials will be discussed, and strategies for further improvement will be proposed. Here, we also present our new results on the study of nanoporous Pt catalysts that are prepared through the chemical dealloying of magnetron-sputtered Pt–Cu thin films for the hydrolysis of sodium borohydride. We discuss the capabilities of the technique to tune the microstructure from columnar to closed porous microstructures, which, coupled with dealloying, produces more active supported catalysts with lower noble metal loading. At the end, we briefly mention the application of PVD for the preparation of supported catalysts for the hydrolysis of ammonia borane, another hydrogen generating reaction of high interest nowadays. 相似文献
13.
With the aim of designing an efficient hydrogen generator for portable fuel cell applications nickel–cobalt–boride (Ni–Co–B) catalysts were prepared by a chemical reduction method and their catalytic hydrolysis reaction with alkaline NaBH4 solution was studied. The performance of the catalysts prepared from NaBH4 solution with NaOH, and without NaOH show different hydrogen generation kinetics. The rate of hydrogen generation was measured using Ni–Co–B catalyst as a function of the concentrations of NaOH and NaBH4, as well as the reaction temperature, in the hydrolysis of alkaline NaBH4 solution. The hydrogen generation rate increases for lower NaOH concentrations in the alkaline NaBH4 solution and decreases after reaching a maximum at 15 wt.% of NaOH. The hydrogen generation rate is found to be constant with respect to the concentration of NaBH4 in the alkaline NaBH4 solution. The activation energy for hydrogen generation is found to be 62 kJ mol−1, which is comparable with that of hydrogen generation by a ruthenium catalyst. 相似文献
14.
Meryem Sena Akkuş Hatice Begüm Murathan Derya Öncel Özgür Gülay Özkan Göksel Özkan 《International Journal of Hydrogen Energy》2018,43(23):10734-10740
This study aims to produce H2 from sodium borohydride (NaBH4) and to initiate its hydrolysis at elevated temperature in the absence of a catalyst. Experimental results indicated that the hydrogen generation yield increased up to %99 at 150 °C in the NaBH4 concentration of %5 wt in the acidic medium. It can be concluded that experimental characterization of the by-products is quite important since they affected the reaction mechanism or pathway. When the experiments are carried out under aqueous condition, the primary by- product is sodium metaborate while it is boric acid under acidic condition. It is postulated that by-product boric acid decreased the mass transfer limitation due to its higher solubility that prevents the formation of shell and thus increases the contact area between NaBH4 and vapor. A series of fed-batch reactions were performed to confirm the hypothesis, and the conversions of NaBH4 reached 99% under the acidic condition. 相似文献
15.
N. Patel B. PattonC. Zanchetta R. FernandesG. Guella A. KaleA. Miotello 《International Journal of Hydrogen Energy》2008
In this work we study the hydrogen generation by catalytic hydrolysis of alkaline NaBH4 solution employing Pd-supported on carbon powder (Pd/C) as well as in form of Pd and Pd–C thin films synthesized by pulsed laser deposition (PLD). Two sets of samples were prepared: (1) pure Pd catalyst films which were bombarded with Ar+ ions at different ions fluence in order to increase the surface roughness; (2) highly irregular C film were deposited by using different Ar pressure in the PLD chamber prior to deposition of the Pd film to further increase the surface area for the active Pd catalyst. Surface morphology was studied by using scanning electron microscopy (SEM) and atomic force microscopy (AFM) while compositional analysis was performed by using energy dispersive spectroscopy (EDS). Cone like structure on the surface of the Pd film developed by Ar+ ion bombardment was not efficient to enhance the catalytic activity of the Pd. Pd/C films showed higher catalytic activity in comparison to Pd/C powders when the same amount of catalyst is used. The results are discussed in relation to the morphology of the C-films. 相似文献
16.
《International Journal of Hydrogen Energy》2019,44(39):21716-21725
Carbon nanofibers (CNFs) incorporating NiS nanoparticles (NPs), namely NiS@CNFs were prepared by one-step electrospinning and successfully employed as a catalyst for hydrogen production from hydrolytic dehydrogenation of sodium borohydride (SBH). As-prepared NiS@CNFs, composed of polyacrylonitrile (PAN), nickel acetate, and ammonium sulfide, was calcined at 900 °C in argon atmosphere, and characterized using standard surface science techniques. The combined results revealed the growth of NiS NPs inside the CNFs, hence confirmed the presence of elemental Ni, S, and C. The as-prepared NiS@CNFs catalyst has a significantly higher surface area (650.92 m2/g) than the reported value of 376 m2/g. Importantly, this catalyst exhibited a much higher catalytic performance, for H2 production from SBH, than that of Ni@CNFs, as evidenced by its low activation energy (∼25.11576 kJ/mol) and their Rmax values of 2962 vs. 1770 mL/g·min. Recyclability tests on using NiS@CNFs catalyst showed quantitatively production (∼100% conversion) of H2 from SBH and retained up to 70% of its initial catalytic activity after five successive cycles. The low cost and high catalytic performance of the designed NiS@CNFs catalyst enable facile H2 production from readily available hydrogen storage materials. 相似文献
17.
18.
Currently, the energy requirements of the entire world are mostly provided by hydrocarbon-based fossil fuels, such as coal, fuel oil, or natural gas. Because of environmental pollution, decrease in energy sources, and difficulties in storing electricity, more attention is dedicated to new sources of energy, such as hydrogen. Presently, sodium borohydride (NaBH4) appears to be an excellent hydrogen-storage medium due to its high theoretical hydrogen yield by weight, 10.6%. The main aim of the present study is to investigate NaBH4 production from ulexite mineral (NaCaB5O9·8H2O). The experimental investigation consists of four steps, such as (1) Characterization of NaCaB5O9·8H2O by X-ray diffraction, differential thermal and thermogravimetric analysis, scanning electron microscopy, and attenuated total reflectance of Fourier-transform infrared spectroscopy; (2) Preparation of ulexite–borosilicate glass (NaCaB5O9·SiO2); (3) Synthesis of NaBH4 from ulexite–borosilicate glass; and (4) Separation of NaBH4 from the reaction mixture. NaBH4 can thus be produced by heating ulexite mineral form of borosilicate glass with metallic sodium under 3-atm. hydrogen pressure at 450–500 °C for 4 h. 相似文献
19.
Joydev Manna Binayak Roy Manvendra Vashistha Pratibha Sharma 《International Journal of Hydrogen Energy》2014
Cobalt boride is known to act as a catalyst to facilitate the hydrolysis reaction of sodium borohydride. The catalytic nature of cobalt boride is immensely dependent upon the synthesis procedure and reaction conditions used, especially on the relative amount of Co(II) and borohydride used for catalyst preparation. In the current work a set of catalysts were prepared by varying the cobalt(II) and borohydride ratio in the reactant solution. The prepared catalysts were well characterized using different characterizing tools like XRD, FTIR, FEG-SEM, FEG-TEM, ICP-AES and XPS. The effect of the catalyst on the hydrolysis of sodium borohydride was thoroughly studied and reported in the current work. The catalytic activity of the catalyst was observed to be highly dependent on the reduced cobalt content. It was observed that the excess amount of borohydride used to synthesize the catalyst, was not increasing the catalytic activity after the complete reduction of cobalt. 相似文献
20.
《International Journal of Hydrogen Energy》2020,45(22):12331-12346
The purpose of this study were to prepare the novel supported bimetallic cobalt-nickel catalysts on the core-shell magnetic nanocomposite of activated carbon derived from wood by sequential and co-deposition-precipitation. The performance of the prepared catalyst was evaluated for the hydrogen generation from hydrolysis of sodium borohydride. The magnetic catalysts were characterized by applying the XRD, XPS, FTIR, FESEM, TEM, ICP, BET and VSM tests. The hydrogen generation rate was increased with the reduction of calcination temperature. The well dispersed magnetic nanoparticles were fabricated with average size below of 30 nm which was confirmed by TEM, FESEM and XRD results. The activity of the prepared samples with respect to the preparation method was illustrated to follow a specific order: Co/Ni/MWAC > Ni/Co/MWAC > Co–Ni/MWAC. The developed model derived from design of experiments could correlate the operating parameters with the experimental data while the correlation coefficient was achieved to be 0.99. The hydrogen generation rate was increased with increasing the reaction temperature and the concentration of sodium borohydride in the alkaline solutions. The hydrogen generation rate was measured to be 740.70 ml min−1. gcat−1 in the presence of the Co/Ni/MWAC at 30 °C. The experimental study also indicated that the hydrolysis of sodium borohydride was a zero order type reaction and the activation energy was calculated 40.70 kJ mol−1. The stability of the prepared sample was also investigated for six cycles which showed the acceptable performance of the synthesized catalyst for the practical applications. 相似文献