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1.
Low cost transition metal catalysts with high performance are attractive for the development of on-board hydrogen generation systems by catalytic hydrolysis of sodium borohydride (NaBH4) in fuel cell fields. In this study, hydrogen production from alkaline NaBH4 via hydrolysis process over carbon-supported cobalt catalysts was studied. The catalytic activity of the supported cobalt catalyst was found to be highly dependent on the calcination temperatures. The hydrogen generation rate increases with calcination temperatures in the range of 200–400 °C, but a high calcination temperature above 500 °C led to markedly decreased activity. X-ray diffraction patterns reveal that the catalysts experience phase transition from amorphous Co–B to crystalline cobalt hydroxide with increase in calcination temperatures. The reaction performance is also dependent on the concentration of NaBH4, and the hydrogen generation rate increases for lower NaBH4 concentrations and decreases after reaching a maximum at 10 wt.% of NaBH4. 相似文献
2.
Yan Liang Hong-Bin DaiLai-Peng Ma Ping WangHui-Ming Cheng 《International Journal of Hydrogen Energy》2010
The catalyst with high activity and durability plays a crucial role in the hydrogen generation systems for the portable fuel cell generators. In the present study, a ruthenium supported on graphite catalyst (Ru/G) for hydrogen generation from sodium borohydride (NaBH4) solution is prepared by a modified impregnation method. This is done by surface pretreatment with NH2 functionalization via silanization, followed by adsorption of Ru (III) ion onto the surface, and then reduced by a reducing agent. The obtained catalyst is characterized by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Very uniform Ru nanoparticles with sizes of about 10 nm are chemically bonded on the graphite surface. The hydrolysis kinetics measurements show that the concentrations of NaBH4 and NaOH all exert considerable influence on the catalytic activity of Ru/G catalyst towards the hydrolysis reaction of NaBH4. A hydrogen generation rate of 32.3 L min−1 g−1 (Ru) in a 10 wt.% NaBH4 + 5 wt.% NaOH solution has been achieved, which is comparable to other noble catalysts that have been reported. 相似文献
3.
《International Journal of Hydrogen Energy》2019,44(33):17586-17594
In this study, it is aimed to investigate hydrogen (H2) generation from sodium borohydride (NaBH4) hydrolysis by multi-walled carbon nanotube supported platinum catalyst (Pt/MWCNT) under various conditions (0–0.03 g Pt amount catalyst, 2.58–5.03 wt % NaBH4, and 27–67 °C) in detail. For comparison, carbon supported platinum (Pt/C) commercial catalyst was used for H2 generation experiments under the same conditions. The reaction rate of the experiments was described by a power law model which depends on the temperature of the reaction and concentrations of NaBH4. Kinetic studies of both Pt/MWCNT and Pt/C catalysts were done and activation energies, which is the required minimum energy to overcome the energy barrier, were found as 27 kJ/mol and 36 kJ/mol, respectively. Pt/MWCNT catalyst is accelerated the reaction less than Pt/C catalyst while Pt/MWCNT is more efficient than Pt/C catalyst, they are approximately 98% and 95%, respectively. According to the results of experiments and the kinetic study, the reaction system based on NaBH4 in the presence of Pt/MWCNT catalyst can be a potential hydrogen generation system for portable applications of proton exchange membrane fuel cell (PEMFC). 相似文献
4.
《International Journal of Hydrogen Energy》2021,46(73):36137-36151
Hydrogen generation through hydrolysis of sodium borohydride was examined over a series of supported cobalt nano particles as novel catalysts. For the first time extracted Glucomannan from Orchis Mascula used as a suitable matrix for preparation and stabilization of cobalt catalysts. Insoluble glucomannan obtained by polymerization reaction in the presence of MBA cross-linker and MAA monomer. Size, morphology and hydrogen generation activity of Co-glucomannan powders are studied by varying MAA/MBA ratios. XRD, XPS, FE-SEM and TEM techniques were used to characterization of obtained catalysts. All nano catalysts are formed in amorphous phase. Electron microscopic images confirmed that almost all particles are less than 10 nm. It is shown, cobalt particles are dispersed on the surface of glucomannan polymer without agglomeration. Catalytic activity of obtained Co-glucomannan are tested on hydrogen generation over hydrolysis of sodium borohydride reaction. Kinetic studies were applied to determine partial order respect to catalyst dosage and initial concentration of sodium borohydride. Finally, Arrhenius equation was used to find activation energy of hydrolysis sodium borohydride reaction over Co-glucomannan nano catalyst. 相似文献
5.
The present paper reports preliminary results relating to a search for durable cobalt-based catalyst intended to catalyze the hydrolysis of sodium borohydride (NaBH4). Fluorination of Co [Suda S, Sun YM, Liu BH, Zhou Y, Morimitsu S, Arai K, et al. Catalytic generation of hydrogen by applying fluorinated-metal hydrides as catalysts. Appl Phys A 2001; 72: 209–12.] has attracted our attention whereas the fluorination of Co boride has never been envisaged so far. Our first objective was to compare the reactivity of fluorinated Co with that of Co boride. We focused our attention on the formation of Co boride from fluorinated Co. Our second objective was to show the fluorination effect on the reactivity of Co. Our third objective was to find an efficient, durable Co catalyst. It was observed a limited stabilization of the Co surface by virtue of the fluorination, which made the formation of surface Co boride more difficult while the catalytic activity was unaltered. The fluorination did not affect the number of surface active sites. Nevertheless, it did not prevent the formation of Co boride. The fluorination of Co boride was inefficient. Hence, fluorination is a way to gain in stabilization of the catalytic surface but it is quite inefficient to hinder the boride formation. Accordingly, it did not permit to compare the reactivity of Co boride with that of Co. 相似文献
6.
Co-B catalysts were prepared by the chemical reduction of CoCl2 with NaBH4 for hydrogen generation from borohydride hydrolysis. The catalytic properties of the Co-B catalysts were found to be sensitive to the preparation conditions including pH of the NaBH4 solution and mixing manner of the precursors. A Co-B catalyst with a very high catalytic activity was obtained through the formation of a colloidal Co(OH)2 intermediate. The ultra-fine particle size of 10 nm accounted for its super activity for hydrogen generation with a maximum rate of 26 L min−1 g−1 at 30 °C. The catalyst also changed the hydrolysis kinetics from zero-order to first-order. 相似文献
7.
A. Pozio M. De Francesco G. Monteleone R. Oronzio S. Galli C. D’Angelo M. Marrucci 《International Journal of Hydrogen Energy》2008
Extended application of hydrogen as energy carrier demands an economical, safe and reliable technology for storage. In particular, chemical hydrides appear as capable and promising to overcome the issues related to hydrogen safety and handling and to be considered competitive with respect to conventional fuels. 相似文献
8.
《International Journal of Hydrogen Energy》2017,42(26):16529-16537
In the present study, nanostructured Co–Ni–P catalysts have been successfully prepared on Cu sheet by electroless plating method. The morphologies of Co–Ni–P catalysts are composed of football-like, granular, mockstrawberry-like and shuttle-like shapes by tuning the depositional pH value. The as-deposited mockstrawberry-like Co–Ni–P catalyst exhibits an enhanced catalytic activity in the hydrolysis of NaBH4 solution. The hydrogen generation rate and activation energy are 2172.4 mL min−1 g−1 and 53.5 kJ mol−1, respectively. It can be inferred that the activity of catalysts is the result of the synergistic effects of the surface roughness, the particle size and microscopic architectures. Furthermore, the stability of mockstrawberry-like Co–Ni–P catalyst has been discussed, and the hydrogen generation rate remains about 81.4% of the initial value after 5 cycles. 相似文献
9.
In this review, a convenient hydrogen generation technology based on sodium borohydride and water as hydrogen carriers has been summarized. The recent progresses in the development of the hydrogen generation from sodium borohydride hydrolysis are reviewed. The NaBH4 hydrolysis behavior is discussed in detail. From reported results, it is considered that hydrogen generation from sodium borohydride hydrolysis is a feasible technology to supply hydrogen for the PEMFC. It has been found that the reported results are encouraging although there are some engineering problems that lie ahead. The critical issues of this hydrogen generation technology have been highlighted and discussed. 相似文献
10.
Chin-Chang Yang Miao-Sheng ChenYu-Wen Chen 《International Journal of Hydrogen Energy》2011,36(2):1418-1423
Generation of hydrogen by hydrolysis of alkali metal hydrides has attracted attention. Unsupported CoB catalyst demonstrated high activity for the catalytic hydrolysis of NaBH4 solution. However, unsupported CoB nanoparticles were easy to aggregate and difficult to reuse. To overcome these drawbacks, CoB/SiO2 was prepared and tested for this reaction. Cobalt (II) acetate precursor was loaded onto the SiO2 support by incipient-wetness impregnation method. After drying at 100 °C, Co cations were deposited on the support. The dried sample was then dispersed in methanol/water solution and then fully reduced by NaBH4 at room temperature. The catalyst was characterized by N2 sorption, XRD and XPS. The results indicated that the CoB on SiO2 possessed amorphous structure. B and Co existed both in elemental and oxidized states. SiO2 not only affected the surface compositions of CoB, but also affected the electronic states of Co and B. B0 could donate partial electron to Co0. The structure effect caused by the SiO2 support helped to prevent CoB nanocluster from aggregation and therefore the activity increased significantly on hydrolysis of alkaline NaBH4 solution. The CoB/SiO2 catalyst showed much higher activity than the unsupported CoB catalyst. At 298 K, the hydrogen generation rate on CoB/SiO2 catalyst was 4 times more than that on the unsupported CoB catalyst. The hydrogen generation rate was as high as 10,586 mL min−1 g−1 catalyst at 298 K. CoB/SiO2 is a very promising catalyst for this reaction. 相似文献
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.
Ouardia AkdimRita Chamoun Umit B. Demirci Youssef ZaatarAntonio Khoury Philippe Miele 《International Journal of Hydrogen Energy》2011,36(22):14527-14533
Electrodeposition was used to deposit cobalt over polycarbonate membrane (PCM), which was used as stable supported catalyst in hydrolysis of sodium borohydride NaBH4. We selected PCM as support owing to its lightness, easy handling, stability, and porous structure with nanosized channels. Our primary objective was to obtain a catalytic film resistant to both physical degradation and delamination while H2 bubbled on its surface. A thin film consisting of mushroom-like cobalt nanoarchitectures were prepared. By SEM, we observed that it is strongly embedded into the PCM thickness, with the anchoring occurring through the channels. This shaped catalyst was mechanically stable and did not show degradation during the reaction. The main results are reported and discussed in details herein. 相似文献
13.
《International Journal of Hydrogen Energy》2022,47(16):9643-9652
Effective and reusable catalysts with high performance are essentially necessary for NaBH4 based on-demand hydrogen generators to the widespread use for energy conversion in fuel cell power systems. Herein, we report a facile synthesis of surfactant-directed polypyrrole-supported Co–W–B nanoparticles as a robust catalyst for efficient hydrolysis of NaBH4 reaction. This non-noble metal catalyst provides much higher catalytic activity than a conventional cobalt boride catalyst. By incorporating tungsten to catalyst composition and tuning molar ratio of W/(Co + W), about a four-fold higher hydrogen generation rate was attained compared to bare Co–B. Among the all catalysts tested, Co–W–B/PPy with 7.5% W possessed the remarkable catalytic performance of 9.92 L min?1 g?1 and high stability over five cycles with the apparent activation energy of 49.18 kJ mol?1. 相似文献
14.
《International Journal of Hydrogen Energy》2020,45(18):10745-10753
In recent years, catalytic hydrolysis of sodium borohydride is considered to be a promising approach for hydrogen generation towards fuel cell devices, and highly efficient and noble-metal-free catalysts have attracted increasing attention. In our present work, Co3O4 nanocubes are synthesized by solvothermal method, and then vapor-phase phosphorization treatment is carried out for the preparation of novel Co−O−P composite nanocatalysts composed of multiple active centers including Co, CoO, and Co2P. For catalyst characterization, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and X-ray photoelectric spectroscopy (XPS) are conducted. Optimal conditions for catalyst preparation and application were investigated in detail. At room temperature (25 °C), maximum hydrogen generation rate (HGR) is measured to be 4.85 L min−1 g−1 using a 4 wt% NaBH4 − 8 wt% NaOH solution, which is much higher than that of conventional catalysts with single component reported in literature. It is found that HGR remarkably increases with the increasing of reaction temperature, and apparent activation energy for catalytic hydrolysis of NaBH4 is calculated to be 63 kJ mol−1. After reusing for five times, the Co−O−P composite nanocatalysts still retains 78% of the initial activity. 相似文献
15.
16.
《International Journal of Hydrogen Energy》2023,48(18):6788-6797
At present, a novel and active catalyst, RuW/MWCNT catalyst, was successfully synthesized to complete the hydrolysis reaction of sodium borohydride (NaBH4). The activity of Ru catalyst was increased by adding tungsten (W) to ruthenium (Ru) on multi-walled carbon nanotube (MWCNT) support. Surface characterization of the catalyst was performed with scanning electron microscope (SEM-EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmissing electron microscope (TEM) analysis methods. SEM-EDX revealed that RuW (95:5) catalyst metal ratio was obtained at desired nominal ratio. XRD characterization revealed that W addittion to the Ru structure increased its activity by forming an alloy. W addition Ru altered the electronic structure of the Ru. Parameters affecting the hydrolysis performance of RuW/MWCNT catalyst such as temperature, amount of catalyst, NaBH4 concentration and sodium hydroxide (NaOH) concentration were investigated. Adding NaOH to the reaction vessel reduced the activity of the RuW/MWCNT catalyst. From the hydrolysis measurements, the activation energy of RuW(95–5)/MWCNT catalyst was found to be 16.327 kjmol?1, the reaction order as 0.61 and the initial rate as 95,841,4 mL H2gcatmin?1. The stability of the RuW/MWCNT catalyst was tested using 5 times and it was observed that this novel RuW/MWCNT catalyst could complete the hydrolysis reaction despite repeated use. 相似文献
17.
The present research paper reports preliminary results about the utilization of anhydrous aluminum chloride (AlCl3) for accelerating hydrogen generation through hydrolysis of aqueous solution of sodium borohydride (NaBH4) at 80 °C. To the best of our knowledge, AlCl3 has never been considered for that reaction although many transition metal salts had already been assessed. AlCl3 reactivity was compared to those of AlCl3·6H2O, AlF3, CoCl2, RuCl3 and NiCl2. With AlCl3 and a NaBH4 solution having a gravimetric hydrogen storage capacity (GHSC) of 2.9 wt.%, almost 100% hydrogen was generated in few seconds, i.e., with a hydrogen generation rate (HGR) of 354 L min−1 g−1(Al). This HGR is one of the highest rates ever reported. Higher HGRs were obtained by mixing AlCl3 with CoCl2, RuCl3 or NiCl2. For example, the system RuCl3:AlCl3 (50:50 mass proportion) showed a HGR > 1000 L min−1 g−1(Ru:Al). The hydrolysis by-products (once dried) were identified (by XRD, IR and elemental analysis) as being Al(OH)3, NaCl and Na2B(OH)4Cl and it was observed that even in situ formed Al(OH)3 has catalytic abilities with HGRs of 5 L min−1 g−1(Al). All of these preliminary results are discussed, which concludes that AlCl3 has a potential as accelerator for single-use NaBH4-based storage system. 相似文献
18.
《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
19.
Valentina G. Minkina Stanislav I. Shabunya Vladimir I. Kalinin Vladimir V. Martynenko Alevtina L. Smirnova 《International Journal of Hydrogen Energy》2012
Experimental results regarding long-term stability of the alkaline-water borohydride solutions for hydrogen generation are presented. The influence of the concentration of sodium borohydride and sodium hydroxide on the rate of borohydride hydrolysis is analyzed at various temperatures, such as 25 °C, 40 °C, and 80 °C, and various concentrations of NaOH. The rate of hydrolysis decreases with the increase of the water to sodium borohydride mole ratio. For diluted solutions at H2O/NaBH4 >30, the rate of hydrolysis and hydrogen generation at a given temperature remains constant. At room temperature in 1.0 N NaOH, the degree of hydrolysis is 0.01% NaBH4/h that meets the stability requirements for the borohydride solutions during the long-term storage. 相似文献
20.
Amit Ashok VernekarSandesh Tukaram Bugde Santosh Tilve 《International Journal of Hydrogen Energy》2012,37(1):327-334
In this article, we report Co-Co2B and Ni-Ni3B nanocomposites as catalyst for hydrogen generation from alkaline sodium borohydride. Kinetic studies of the hydrolysis of sodium borohydride with Co-Co2B and Ni-Ni3B nanocomposites reveal that the concentration of NaBH4 has no effect on the rate of hydrogen generation. Hydrolysis was found to be first order with respect to the concentration of catalyst. The catalytic activity of Co-Co2B was found to be much higher than that of Ni-Ni3B as inferred from the activation energies 35.245 KJ/mol and 55.810 kJ/mol, respectively. Co-Co2B nanocomposites were found to be more magnetic than Ni-Ni3B. These catalysts showed superior recyclability with almost the similar catalytic activities for several hydrolytic cycles supporting the principles of sustainability. Co-Co2B catalyst showed hydrogen generation rate of about 4300 mL/min/g which is comparable to most of the reported good catalysts till date. 相似文献