scholarly journals Study on Hydrolysis of Magnesium Hydride by Interface Control

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yanyan Chen ◽  
Ming Wang ◽  
Fenggang Guan ◽  
Rujun Yu ◽  
Yuying Zhang ◽  
...  
Keyword(s):  
Surface Tension ◽  
Hydrogen Generation ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Magnesium Hydride ◽  
Passivation Layer ◽  
Hydrogen Release ◽  
Generation Process ◽  
High Hydrogen ◽  
Hydrolysis Of

Magnesium hydride (MgH2) is one of the competitive hydrogen storage materials on account of abundant reserves and high hydrogen content. The hydrolysis of MgH2 is an ideal and controllable chemical hydrogen generation process. However, the hydrolyzed product of MgH2 is a passivation layer on the surface of the magnesium hydride, which will make the reaction continuity worse and reduce the rate of hydrogen release. In this work, hydrogen generation is controllably achieved by regulating the change of the surface tension value in the hydrolysis, a variety of surfactants were systematically investigated for the effect of the hydrolysis of MgH2 In the meantime, the passivation layer of MgH2 was observed by scanning electron microscope (SEM), and the surface tension value of the solution with different surfactants were monitored, investing the mechanism of hydrolysis adding different surfactants. Results show that different surfactants have different effects on hydrogen generation. The hydrogen generation capacity from high to low is as follows: tetrapropylammonium bromide (TPABr), sodium dodecyl benzene sulfonate (SDBS), Ecosol 507, octadecyl trimethyl ammonium chloride (OTAC), sodium alcohol ether sulfate (AES), and fatty methyl ester sulfonate (FMES-70). When the ratio of MgH2 to TPABr was 5 : 1, the hydrogen generation was increased by 52% and 28.3%, respectively, at the time of 100 s and 300 s. When hydrolysis time exceeds 80 s, the hydrogen generation with AES and FMES-70 began to decrease; it was reduced by more than 20% at the time of 300 s. SEM reveals that surfactants can affect the crystalline arrangement of Mg(OH)2 and make the passivation layer three-dimensionally layered providing channels for H2O molecules to react with MgH2.

Hydrolysis of MgH2 in MgCl2 solutions as an effective way for hydrogen generation

2021 ◽  
pp. 38-52
Author(s):  
V. Berezovets ◽  
◽  
A. Kytsya ◽  
Yu. Verbovytskyy ◽  
I. Zavaliy ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Strong Acid ◽  
Magnesium Hydride ◽  
Hydrolysis Reaction ◽  
Hydrolysis Rate ◽  
Reaction Yield ◽  
Buffer Solution ◽  
Passivation Film ◽  
Products Of Reaction ◽  
Hydrolysis Of

Magnesium hydride (MgH2) has a high hydrogen storage capacity (7.6 wt%) and the Mg element is abundant on the earth. Due to its strong reduction ability, even at room temperature it can provide the hydrogen yield reaching 15.2 wt% H (1703 mL/g) when interacting with water, which makes it very attractive for the application in supplying hydrogen for autonomous H energy systems. However, the hydrolysis reaction is rapidly inhibited by the Mg(OH)2 passivation layer formed on the surface of MgH2. In order to remove the passivation film and improve the efficiency of the MgH2 hydrolysis process, several methods including alloying, ball milling, changing the aqueous solution, have been successfully utilized. In this paper the process of hydrolysis of magnesium hydride in aqueous solutions of MgCl2 used as a promotor of the interaction has been studied in detail. It was found that the initial hydrolysis rate, pH of the reaction mixture, and overall reaction yield are all linearly dependent of the logarithm of MgCl2 concentration. It has been shown that pH of the reaction mixture in the presence of MgCl2 is well described by considering a system “weak base and its salt with strong acid” type buffer solution. Reference data for this hydrolysis reaction were also carefully analyzed. The mechanism and the kinetic model of the process of MgH2 hydrolysis in water solutions involved passivation of the MgH2 surface by the formed Mg(OH)2 precipitate followed by its repassivation have been proposed. The obtained after the hydrolysis reactions precipitates were studied using XRD and EDS. It was found also that the final products of reaction consist of Mg(OH)2 (brucsite type) and remaining MgH2. This fact shows that the formation of solid species such as MgCl2 xMgO yH2O at the studied conditions is unlikely and decreasing of pH the reaction mixture has a different nature.

Hydrogen generation by both acidic and catalytic hydrolysis of sodium borohydride

2018 ◽  
Vol 5 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Olga V. Netskina ◽  
Tihon N. Filippov ◽  
Oksana V. Komova ◽  
Valentina I. Simagina
Keyword(s):  
Hydrogen Evolution ◽  
Sodium Borohydride ◽  
Hydrogen Generation ◽  
Hydrogen Release ◽  
Catalytic Hydrolysis ◽  
Hydrogen Storage Materials ◽  
Acidic Solutions ◽  
High Concentrations ◽  
Sulfuric And Hydrochloric Acids ◽  
Hydrolysis Of

Abstract Sodium borohydride tablets have been employed as hydrogen-storage materials. Hydrogen release was performed by acidic hydrolysis where solutions of sulfuric and hydrochloric acids were added to the tablets, and by catalytic hydrolysis where water was added tablets of solid-state NaBH4/Co composite. In acidic solutions hydrogen evolution occurred instantaneously, and at high concentrations of acids the releasing hydrogen contained an admixture of diborane. Hydrogen evolution from the solidstate NaBH4/Co composite proceeded at a uniform rate of 13.8±0.1 cm3·min-1, water vapor being the only impurity in the evolving gas.

Recent advances in hydrogen generation process via hydrolysis of Mg-based materials: A short review

2020 ◽  
Vol 816 ◽  
pp. 152634 ◽  
Author(s):  
XiuBo Xie ◽  
Cui Ni ◽  
Baolei Wang ◽  
Yuping Zhang ◽  
Xiangjin Zhao ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Short Review ◽  
Generation Process ◽  
Recent Advances ◽  
Hydrolysis Of

Accelerated Hydrolysis of Solid-state NaBH4/Al System by Co2B Milled with Li for Hydrogen Generation

2016 ◽  
Vol 19 (2) ◽  
pp. 109-115
Author(s):  
Jiasong Chang ◽  
Wenlong Song ◽  
Ting Li ◽  
Jindan Chen ◽  
Hanmei Wu ◽  
...  
Keyword(s):  
Milling Time ◽  
Hydrogen Generation ◽  
Synergetic Effect ◽  
Hydrogen Yield ◽  
Preparation Process ◽  
Preparation Technology ◽  
High Hydrogen ◽  
Hydrolysis Process ◽  
Hydrolysis Of ◽  
Li Content

Co2B catalyst was milled with Al and Li to form Al-Li-Co2B composite, and the hydrogen generation performance of Al-Li-Co2B/NaBH4 system was investigated in this study. 100% hydrogen yield was reached, and high hydrogen generation rate was regulated by optimizing the composition design and preparation technology. The improvement was attributed to the synergetic effect of Co2B and Li in the preparation process, whereas a large specific surface area was obtained with the increase in Li content, Co2B, and milling time. In addition, the catalytic activity of Co2B and LiOH from Li hydrolysis was heightened for the hydrolysis of the Al/NaBH4 system because of the addition of Al(OH)3, LiAl2(OH)7.xH2O, and NaBO2 in the hydrolysis process.

Combined Hydrogen Generation from Al/NiCl2 Powder and Alkaline NaBH4 Solution for Portable Fuel Cell

2012 ◽  
Vol 16 (1) ◽  
pp. 9-12
Author(s):  
Yan Ling An ◽  
Chao Li ◽  
Bin Hong Tang ◽  
Xia Xiao ◽  
Tian Zhe Zhang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Catalytic Effect ◽  
Hydrogen Generation ◽  
Generation Rate ◽  
Hydrogen Yield ◽  
High Hydrogen ◽  
Composition Design ◽  
Naoh Solution ◽  
Al Powder ◽  
Hydrolysis Of

Hydrolysis of Al and NaBH4 for hydrogen generation has obtained considerable attention as a portable hydrogen source system. In this paper, we report a new combined hydrogen generation from Al powder and alkaline NaBH4 solution activated by NiCl2 additive. The system is characterized as the followed features: the interaction of Al/NaBH4 hydrolysis, catalytic effect of Ni2B for Al and NaBH4, Al hydrolysis stimulated by NaOH solution. The effects which affect the hydrogen generation performance of the system were studied. The results showed that a favorable combination of high hydrogen yield and high hydrogen generation rate might be obtained via the optimized composition design. Therefore, the system may be developed as a portable hydrogen source system.

Improved Commercialized Lithium Titanate Performance in Lithium-ion Batteries by Annealing

2012 ◽  
Vol 16 (1) ◽  
pp. 19-23
Author(s):  
Xinxi Li ◽  
Guoqing Zhang ◽  
Zhongqiong Xiong ◽  
Junqiao Xiong ◽  
Yongping Qiu
Keyword(s):  
Lithium Ion Batteries ◽  
Catalytic Effect ◽  
Hydrogen Generation ◽  
Lithium Ion ◽  
Lithium Titanate ◽  
Hydrogen Yield ◽  
High Hydrogen ◽  
Naoh Solution ◽  
Al Powder ◽  
Hydrolysis Of

Hydrolysis of Al and NaBH4 for hydrogen generation has obtained considerable attention as a portable hydrogen source system. In this paper, we report a new combined hydrogen generation from Al powder and alkaline NaBH4 solution activated by NiCl2 additive. The system is characterized as the followed features: the interaction of Al/NaBH4 hydrolysis, catalytic effect of Ni2B for Al and NaBH4, Al hydrolysis stimulated by NaOH solution. The effects which affect the hydrogen generation performance of the system were studied. The results showed that a favorable combination of high hydrogen yield and high hydrogen generation rate might be obtained via the optimized composition design. Therefore, the system may be developed as a portable hydrogen source system.

Investigations of Surface Tension of Binary Nanofluids

2011 ◽  
Vol 347-353 ◽  
pp. 786-790 ◽  
Author(s):  
Liu Yang ◽  
Kai Du
Keyword(s):  
Surface Tension ◽  
Carbon Black ◽  
Water Solution ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Al2o3 Nanoparticles ◽  
Ammonia Content ◽  
Ammonia Water ◽  
Carbon Black Nanoparticles ◽  
Dodecyl Benzene Sulfonate

In this paper, several types of binary nanofluids were prepared by mixing TiN, SiC, carbon black nanoparticles with emulsifier OP-10, and Al2O3 nanoparticles with sodium dodecyl benzene sulfonate (SDBS), to ammonia-water solution, respectively. The influences of ammonia, nanoparticles, and surfactant on the surface tension of the binary nanofluids are investigated by using a QBZY-1 digital surface tensiometer. The results show that the surface tensions of ammonia water decrease approximately linearly with the increase of ammonia content. For the nanofluid (TiN, SiC) without surfactant, the nanoparticles can softly reduce the surface tension of the binary nanofluids. While for the nanofluid (Al2O3, carbon black) containning surfactant, the existences of surfactant greatly reduce the surface tension of the binary nanofluids. When the content of surfactant is lower than critical micelle concentration(CMC), adding nanoparticles can increase the surface tension of the fluids, which may be caused by the decrease of the “free” surfactant content induced by the adsorption of surfactant on the surface of nanoparticles.

Investigation into the Catalytic Ability of Fibrillar Co-Y-B Catalyst in Hydrogen Production from Hydrolysis of Sodium Borohydride

2013 ◽  
Vol 724-725 ◽  
pp. 773-777
Author(s):  
Jing Chang ◽  
Fang Lin Du
Keyword(s):  
Sodium Borohydride ◽  
Hydrogen Generation ◽  
Chemical Reduction ◽  
Xrd Analysis ◽  
Generation Rate ◽  
Pure Hydrogen ◽  
Generation Process ◽  
Catalytic Reactivity ◽  
Hydrolysis Of ◽  
Structural Characterizations

The hydrolysis reaction of sodium borohydride (NaBH4) can generate highly pure hydrogen. In this paper, the Co-Y-B catalyst is prepared using the simple chemical reduction method. Its catalytic reactivity is investigated for different NaBH4 concentrations, NaOH concentrations, the catalyst amounts and the reacting temperatures. When the Y/(Co+Y) mole ratio in catalyst arrives at 40 %, the catalysts show the best catalytic ability. There is an optimum range, around 8 wt.% for NaBH4 concentration and also 8 wt.% for NaOH concentration, respectively, in which the hydrogen generation rate performed best. Both the large catalyst amount and the high reacting temperature are beneficial to promote the hydrogen generation rate. Structural characterizations of the fibrillar catalysts are carried out in SEM and XRD analysis. The value of activation energy for the hydrogen generation process is calculated to be 48.02 kJ/mol and it compares favorably with some other previously reported values.

Study of Influence Factors on Wettability of Coal Dust

2013 ◽  
Vol 724-725 ◽  
pp. 1050-1053
Author(s):  
Yin Yu Sun ◽  
Rong Chun Nie ◽  
Lin Lin Zhang
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Fourier Transform ◽  
Coal Dust ◽  
Sodium Dodecyl ◽  
Influence Factors ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Tween 80 ◽  
Benzene Sulfonate ◽  
Dodecyl Benzene Sulfonate

In this study, coal samples of experimental come from the raw coal of Wangfenggang and Qidong. Sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), water-reducing admixture NF and Tween-80 are choosed as surfactants. The influence factors on wettability of coal dust were characterized by contact angle meter, fourier transform infrared spectroscopy (FTIR) and surface tension experiment. The research shows that the effect of solution on wettability of coal dust is mainly depended on the surface structure of coal dust, type and concentration of solution.

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