The effect of various cations/anions for MgH2 hydrolysis reaction

Yuan, Chongyang; Chen, Wei; Yang, Zunxian; Huang, Zhenguo; Xia, Guanglin

doi:10.1016/j.jmst.2020.09.036

Cited by 32 publications

(11 citation statements)

References 30 publications

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“…The values of k were then used to calculate using the Arrhenius equation. 22 Figure 5b displays an Arrhenius plot for the hydrolysis of the composite in H 2 O. The R 2 value is 0.97, which indicates that the Arrhenius equation can be used to describe hydrolysis.…”

Section: Hydrolysis Kinetics and Reaction Activation Energy Of Thementioning

confidence: 93%

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH₂

Zhu

Wang

Zeng

et al. 2022

ACS Appl. Energy Mater.

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Magnesium hydride (MgH 2 ) is one of the most promising candidates for hydrogen generation materials due to the benign byproduct Mg(OH) 2 . However, the low solubility of Mg(OH) 2 inevitably causes sluggish hydrolysis kinetics and low hydrogen yield. Herein, a facile strategy is reported to promote the hydrolysis performance of MgH 2 viain situ formation of metal borohydrides (M(BH 4 ) x ). MgH 2 @M(BH 4 ) x composites are synthesized by ball milling of MgH 2 and cheap metaborates. Different ball-milled durations of NaBO 2 metaborate and electronegativities (χ p ) of cation elements of metaborates (i.e., KBO 2 , NaBO 2 , LiBO 2 , Ca(BO 2 ) 2 , and Mg(BO 2 ) 2 ) were compared to reveal that the MgH 2 −4 mol % NaBO 2 composite after 6 h ball milling has the best hydrolysis performance. Specifically, it could release 1597.2 mL g −1 H 2 (95% theoretical H 2 ) in 60 min with a fast hydrolysis rate of 1216 mL g −1 min −1 H 2 during the first minute of the hydrolysis at 55 °C. Our finding is expected to facilitate the application of MgH 2 for on-site hydrogen generation.

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Section: Hydrolysis Kinetics and Reaction Activation Energy Of Thementioning

confidence: 93%

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH₂

Zhu

Wang

Zeng

et al. 2022

ACS Appl. Energy Mater.

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“…However, the dense passivation layer of Mg(OH) 2 will prevent the further contact of water with intimal MgH 2 , which results in sluggish hydrolysis kinetics [17,18]. In the process of hydrolysis, in order to remove the passivation layer and promote the hydrolysis reaction of MgH 2 , researchers have made great efforts, such as the introduction of various cations/anions in the solution [19][20][21], the addition of additives [21][22][23], alloying [16,[24][25][26][27], reduce Mg particle size [28], and so on. These methods play an important role in improving the hydrolysis kinetics and hydrogen generation capacity to a certain extent.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Generation by Hydrolysis of MgH2-LiH Composite

Han

Peng

et al. 2022

Materials

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As a most promising material for hydrogen generation by hydrolysis, magnesium hydride (MgH2) is also trapped by its yielded byproduct Mg(OH)2 whose dense passivated layers prevent the further contact of intimal MgH2 with water. In this work, LiH, as a destroyer, has been added to promote the hydrogen properties of MgH2. The results demonstrate that even 3 wt % LiH was added into MgH2-G, the hydrogen generation yield can increase about 72% compared to the hydrogen generation yield of MgH2-G. The possible mechanism is that Mg2+ from the hydrolysis of MgH2 preferentially bound with OH− ions from the hydrolysis of LiH to form Mg(OH)2 precipitation, which is dispersed in water rather than coated on the surface of MgH2. Moreover, adding MgCl2 into hydrolysis solution, using ball milling technology, and increasing the hydrolysis temperature can make the hydrolysis rate higher and reaction process more complete. It is noted that a too high weight ratio of LiH with too high of a hydrolysis temperature will make the reaction too violent to be safe in the experiment. We determinate the best experimental condition is that the LiH ratio added into MgH2 is 3 wt %, the hydrolysis temperature is 60 °C, and the concentration of MgCl2 hydrating solution is 1 M. MgH2-LiH composite hydrogen generation technology can meet the needs of various types of hydrogen supply and has broad application prospects.

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“…Owing to the high purity of hydrogen produced by hydrolysis, we can directly employ it as a portable hydrogen source for hydrogen fuel cells. [ 15 , 16 ] To date, the systematically studied hydrolysis material systems include light metals (Mg, Al) [ 17 , 18 , 19 ] and their hydrides (MgH 2 , CaH 2 ), [ 20 , 21 ] and coordination hydrides (MgBH 4 , NaBH 4 ). [ 22 , 23 , 24 , 25 ] Among them, magnesium based material is considered to be a promising material due to its abundant raw materials, inexpensive price and environmental friendliness.…”

Section: Introductionmentioning

confidence: 99%

Supra Hydrolytic Catalysis of Ni₃Fe/rGO for Hydrogen Generation

et al. 2022

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Light metal hydrolysis for hydrogen supply is well suited for portable hydrogen fuel cells. The addition of catalysts can substantially aid Mg hydrolysis. However, there is a lack of clear catalytic mechanism to guide the design of efficient catalysts. In this work, the essential role of nanosized catalyst (Ni3Fe/rGO) in activating micro‐sized Mg with ultra‐rapid hydrolysis process is investigated for the first time. Here, an unprecedented content of 0.2 wt% Ni3Fe/rGO added Mg can release 812.4 mL g−1 hydrogen in just 60 s at 30 °C. Notably, an impressive performance with a hydrogen yield of 826.4 mL g−1 at 0 °C in only 30 s is achieved by the Mg‐2 wt% Ni3Fe/rGO, extending the temperature range for practical applications of hydrolysis. Moreover, the four catalysts (Ni3Fe/rGO, Ni3Fe, Ni/rGO, Fe/rGO) are designed to reveal the influence of composition, particle size, and dispersion on catalytic behavior. Theoretical studies corroborate that the addition of Ni3Fe/rGO accelerates the electron transfer and coupling processes and further provides a lower energy barrier diffusion path for hydrogen. Thus, a mechanism concerning the catalyst as migration relay is proposed. This work offers guidelines designing high‐performance catalysts especially for activating the hydrolysis of micro‐sized light weight metals.

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The effect of various cations/anions for MgH2 hydrolysis reaction

Cited by 32 publications

References 30 publications

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH₂

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH₂

Hydrogen Generation by Hydrolysis of MgH2-LiH Composite

Supra Hydrolytic Catalysis of Ni₃Fe/rGO for Hydrogen Generation

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The effect of various cations/anions for MgH2 hydrolysis reaction

Cited by 32 publications

References 30 publications

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH2

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH2

Hydrogen Generation by Hydrolysis of MgH2-LiH Composite

Supra Hydrolytic Catalysis of Ni3Fe/rGO for Hydrogen Generation

Contact Info

Product

Resources

About

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH₂

Effect of Metaborate Additive Modification on Hydrolysis Performance of MgH₂

Supra Hydrolytic Catalysis of Ni₃Fe/rGO for Hydrogen Generation