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16 pages, 5667 KiB

Open AccessArticle

Effects of Wall Thickness Variation on Hydrogen Embrittlement Susceptibility of Additively Manufactured 316L Stainless Steel with Lattice Auxetic Structures

by Mahmoud Khedr, Atef Hamada, Walaa Abd-Elaziem, Matias Jaskari, Mahmoud Elsamanty, Jukka Kömi and Antti Järvenpää

Materials 2023, 16(6), 2523; https://doi.org/10.3390/ma16062523 - 22 Mar 2023

Cited by 4 | Viewed by 1633

Abstract

In the present study, the hydrogen embrittlement (HE) susceptibility of an additively manufactured (AM) 316L stainless steel (SS) was investigated. The materials were fabricated in the form of a lattice auxetic structure with three different strut thicknesses, 0.6, 1, and 1.4 mm, by [...] Read more.

In the present study, the hydrogen embrittlement (HE) susceptibility of an additively manufactured (AM) 316L stainless steel (SS) was investigated. The materials were fabricated in the form of a lattice auxetic structure with three different strut thicknesses, 0.6, 1, and 1.4 mm, by the laser powder bed fusion technique at a volumetric energy of 70 J·mm⁻³. The effect of H charging on the strength and ductility of the lattice structures was evaluated by conducting tensile testing of the H-charged specimens at a slow strain rate of 4 × 10⁻⁵ s⁻¹. Hydrogen was introduced to the specimens via electrochemical charging in an NaOH aqueous solution for 24 h at 80 °C before the tensile testing. The microstructure evolution of the H-charged materials was studied using the electron backscattered diffraction (EBSD) technique. The study revealed that the auxetic structures of the AM 316L-SS exhibited a slight reduction in mechanical properties after H charging. The tensile strength was slightly decreased regardless of the thickness. However, the ductility was significantly reduced with increasing thickness. For instance, the strength and uniform elongation of the auxetic structure of the 0.6 mm thick strut were 340 MPa and 17.4% before H charging, and 320 MPa and 16.7% after H charging, respectively. The corresponding values of the counterpart’s 1.4 mm thick strut were 550 MPa and 29% before H charging, and 523 MPa and 23.9% after H charging, respectively. The fractography of the fracture surfaces showed the impact of H charging, as cleavage fracture was a striking feature in H-charged materials. Furthermore, the mechanical twins were enhanced during tensile straining of the H-charged high-thickness material. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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12 pages, 5853 KiB

Open AccessArticle

Theoretical and Experimental Studies of Al-Impurity Effect on the Hydrogenation Behavior of Mg

by Jinzhe Lyu, Roman Elman, Leonid Svyatkin and Viktor Kudiiarov

Materials 2022, 15(22), 8126; https://doi.org/10.3390/ma15228126 - 16 Nov 2022

Cited by 3 | Viewed by 929

Abstract

In this paper, we study the influence of hydrogen concentration on the binding energies in magnesium hydrides. The impact of aluminum atom addition on the hydrogenation behavior of magnesium was theoretically and experimentally defined. Doping Al into the Mg lattice allows the uniform [...] Read more.

In this paper, we study the influence of hydrogen concentration on the binding energies in magnesium hydrides. The impact of aluminum atom addition on the hydrogenation behavior of magnesium was theoretically and experimentally defined. Doping Al into the Mg lattice allows the uniform hydrogen distribution in both the fcc and bcc Mg lattice at a low hydrogen concentration (H:Mg < 0.875) to be more energetically favorable. In addition, this leads to bcc Mg lattice formation with a uniform hydrogen distribution, which is more energetically favorable than the fcc Mg lattice when the atomic ratio H:Mg is near 0.875. In addition, compared with the pure Mg, in the Al-doped Mg, the phase transition from the hcp to the fcc structure with a uniform distribution of H atoms induces less elastic strain. Thus, the uniform hydrogen distribution is more favorable, leading to faster hydrogen absorption. Pure magnesium is characterized by cluster-like hydrogen distribution, which decreases the hydrogen diffusion rate. This leads to the accumulation of a higher hydrogen concentration in magnesium with aluminum compared with pure magnesium under the same hydrogenation regimes, which is confirmed experimentally. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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11 pages, 3198 KiB

Open AccessArticle

A Study of Hydrogen Embrittlement of SA-372 J Class High Pressure Hydrogen Storage Seamless Cylinder (≥100 MPA)

by Ruifeng Yin, Ruidong Fu, Ningning Gu and Yongjiu Liu

Materials 2022, 15(21), 7714; https://doi.org/10.3390/ma15217714 - 02 Nov 2022

Cited by 3 | Viewed by 1505

Abstract

The spinning process will lead to changes in the micro-structure and mechanical properties of the materials in different positions of the high-pressure hydrogen storage cylinder, which will show different hydrogen embrittlement resistance in the high-pressure hydrogen environment. In order to fully study the [...] Read more.

The spinning process will lead to changes in the micro-structure and mechanical properties of the materials in different positions of the high-pressure hydrogen storage cylinder, which will show different hydrogen embrittlement resistance in the high-pressure hydrogen environment. In order to fully study the safety of hydrogen storage in large-volume seamless steel cylinders, this chapter associates the influence of the forming process with the deterioration of a high-pressure hydrogen cylinder (≥100 MPa). The anti-hydrogen embrittlement of SA-372 grade J steel at different locations of the formed cylinders was studied experimentally in three cylinders. The hydrogen embrittlement experiments were carried out according to method A of ISO 11114-4:2005. The relationship between tensile strength, microstructure, and hydrogen embrittlement is analyzed, which provides comprehensive and reliable data for the safety of hydrogen storage and transmission. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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15 pages, 2165 KiB

Open AccessArticle

A Comparative Density Functional Theory Study of Hydrogen Storage in Cellulose and Chitosan Functionalized by Transition Metals (Ti, Mg, and Nb)

by Omar Faye, Jerzy A. Szpunar and Ubong Eduok

Materials 2022, 15(21), 7573; https://doi.org/10.3390/ma15217573 - 28 Oct 2022

Cited by 1 | Viewed by 1163

Abstract

The focus of this work is hydrogen storage in pristine cellulose, chitosan, and cellulose. Chitosan doped with magnesium, titanium, and niobium is analyzed using spin unrestricted plane-wave density functional theory implemented in the Dmol³ module. The results of this study demonstrate that [...] Read more.

The focus of this work is hydrogen storage in pristine cellulose, chitosan, and cellulose. Chitosan doped with magnesium, titanium, and niobium is analyzed using spin unrestricted plane-wave density functional theory implemented in the Dmol³ module. The results of this study demonstrate that hydrogen interaction with pure cellulose and chitosan occurred in the gas phase, with an adsorption energy of

E_{b}

= 0.095 eV and 0.090 eV for cellulose and chitosan, respectively. Additionally, their chemical stability was determined as

E_{b}

= 4.63 eV and

E_{b}

= 4.720 eV for pure cellulose and chitosan, respectively, by evaluating their band gap. Furthermore, the presence of magnesium, titanium, and niobium on cellulose and chitosan implied the transfer of an electron from metal to cellulose and chitosan. Moreover, our calculations predict that cellulose doped with niobium is the most favorable medium where 6H₂ molecules are stored compared with molecules stored in niobium-doped chitosan with T_max = 818 K to release all H₂ molecules. Furthermore, our findings showed that titanium-doped cellulose has a storage capacity of five H₂ molecules, compared to a storage capacity of four H₂ molecules in titanium-doped chitosan. However, magnesium-doped cellulose and chitosan have insufficient hydrogen storage capacity, with only two H₂ molecules physisorbed in the gas phase. These results suggest that niobium-doped cellulose and chitosan may play a crucial role in the search for efficient and inexpensive hydrogen storage media. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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10 pages, 3673 KiB

Open AccessArticle

XPS Investigation on Improving Hydrogen Sorption Kinetics of the KSiH₃ System by Using Zr-Based Catalysts

by Anish Tiwari, Shivani Agarwal, Kriti Shrivastava, Takayuki Ichikawa, Ankur Jain and Rini Singh

Materials 2022, 15(21), 7454; https://doi.org/10.3390/ma15217454 - 24 Oct 2022

Cited by 3 | Viewed by 1053

Abstract

The superior hydrogen storage properties makes the KSiH₃ system a potential hydrogen storage material for practical applications. A theoretical capacity of 4.3 wt% bring this material to the front line of all the available hydrogen storage materials; however, the activation barrier of [...] Read more.

The superior hydrogen storage properties makes the KSiH₃ system a potential hydrogen storage material for practical applications. A theoretical capacity of 4.3 wt% bring this material to the front line of all the available hydrogen storage materials; however, the activation barrier of the reaction restricts the system to absorb and desorb hydrogen reversibly at elevated temperatures even if the thermodynamics suggest its room temperature operation. Several catalysts have already been tested to enhance its kinetic properties. In this work, the efforts were made to reduce the activation energy by using Zr-based catalysts to the KSi/KSiH₃ system. The value of activation energy was found to be lowest (i.e., 87 kJ mol⁻¹⁾ for the ZrH₂-added KSiH₃ system. The mechanism of this improvement was investigated by using X-ray photoelectron spectroscopy (XPS). Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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19 pages, 3991 KiB

Open AccessArticle

Magnetically Recovered Co and Co@Pt Catalysts Prepared by Galvanic Replacement on Aluminum Powder for Hydrolysis of Sodium Borohydride

by Anna M. Ozerova, Anastasia A. Skobelkina, Valentina I. Simagina, Oksana V. Komova, Igor P. Prosvirin, Olga A. Bulavchenko, Inna L. Lipatnikova and Olga V. Netskina

Materials 2022, 15(9), 3010; https://doi.org/10.3390/ma15093010 - 21 Apr 2022

Cited by 6 | Viewed by 1782

Abstract

Magnetically recovered Co and Co@Pt catalysts for H₂ generation during NaBH₄ hydrolysis were successfully synthesized by optimizing the conditions of galvanic replacement method. Commercial aluminum particles with an average size of 80 µm were used as a template for the synthesis [...] Read more.

Magnetically recovered Co and Co@Pt catalysts for H₂ generation during NaBH₄ hydrolysis were successfully synthesized by optimizing the conditions of galvanic replacement method. Commercial aluminum particles with an average size of 80 µm were used as a template for the synthesis of hollow shells of metallic cobalt. Prepared Co⁰ was also subjected to galvanic replacement reaction to deposit a Pt layer. X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, and elemental analysis were used to investigate catalysts at each stage of their synthesis and after catalytic tests. It was established that Co⁰ hollow microshells show a high hydrogen-generation rate of 1560 mL·min⁻¹·g_cat⁻¹ at 40 °C, comparable to that of many magnetic cobalt nanocatalysts. The modification of their surface by platinum (up to 19 at% Pt) linearly increases the catalytic activity up to 5.2 times. The catalysts prepared by the galvanic replacement method are highly stable during cycling. Thus, after recycling and washing off the resulting borate layer, the Co@Pt catalyst with a minimum Pt loading (0.2 at%) exhibits an increase in activity of 34% compared to the initial value. The study shows the activation of the catalyst in the reaction medium with the formation of cobalt–boron-containing active phases. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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18 pages, 2999 KiB

Open AccessArticle

Catalytic Behavior of Iron-Containing Cubic Spinel in the Hydrolysis and Hydrothermolysis of Ammonia Borane

by Oksana V. Komova, Valentina I. Simagina, Alena A. Pochtar, Olga A. Bulavchenko, Arcady V. Ishchenko, Galina V. Odegova, Anna M. Gorlova, Anna M. Ozerova, Inna L. Lipatnikova, Elena S. Tayban, Svetlana A. Mukha and Olga V. Netskina

Materials 2021, 14(18), 5422; https://doi.org/10.3390/ma14185422 - 19 Sep 2021

Cited by 4 | Viewed by 1867

Abstract

The paper presents a comparative study of the activity of magnetite (Fe₃O₄) and copper and cobalt ferrites with the structure of a cubic spinel synthesized by combustion of glycine-nitrate precursors in the reactions of ammonia borane (NH₃BH [...] Read more.

The paper presents a comparative study of the activity of magnetite (Fe₃O₄) and copper and cobalt ferrites with the structure of a cubic spinel synthesized by combustion of glycine-nitrate precursors in the reactions of ammonia borane (NH₃BH₃) hydrolysis and hydrothermolysis. It was shown that the use of copper ferrite in the studied reactions of NH₃BH₃ dehydrogenation has the advantages of a high catalytic activity and the absence of an induction period in the H₂ generation curve due to the activating action of copper on the reduction of iron. Two methods have been proposed to improve catalytic activity of Fe₃O₄-based systems: (1) replacement of a portion of Fe²⁺ cations in the spinel by active cations including Cu²⁺ and (2) preparation of highly dispersed multiphase oxide systems, involving oxide of copper. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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Review

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24 pages, 9196 KiB

Open AccessReview

Hydrothermal Reduction of CO₂ to Value-Added Products by In Situ Generated Metal Hydrides

by Xu Zeng, Guodong Yin and Jianfu Zhao

Materials 2023, 16(7), 2902; https://doi.org/10.3390/ma16072902 - 06 Apr 2023

Viewed by 1057

Abstract

An integrated process by coupling hydrothermal reactions, including CO₂ reduction and H₂O dissociation with metals, is proposed. The hydrogen could be rapidly produced under hydrothermal conditions, owing to the special characteristics of high temperature water, generating metal hydrides as intermediates. [...] Read more.

An integrated process by coupling hydrothermal reactions, including CO₂ reduction and H₂O dissociation with metals, is proposed. The hydrogen could be rapidly produced under hydrothermal conditions, owing to the special characteristics of high temperature water, generating metal hydrides as intermediates. Hydrogen production from the H₂O dissociation under hydrothermal conditions is one of the most ideal processes due to its environmentally friendly impact. Recent experimental and theoretical studies on the hydrothermal reduction of CO₂ to value-added products by in situ generated metal hydrides are introduced, including the production of formic acid, methanol, methane, and long-chain hydrocarbons. These results indicate that this process holds promise in respect to the conversion of CO₂ to useful chemicals and fuels, and for hydrogen storage, which could help alleviate the problems of climate change and energy shortage. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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19 pages, 5703 KiB

Open AccessReview

Experimentally Observed Nucleation and Growth Behavior of Mg/MgH₂ during De/Hydrogenation of MgH₂/Mg: A Review

by Jinzhe Lyu, Viktor Kudiiarov and Andrey Lider

Materials 2022, 15(22), 8004; https://doi.org/10.3390/ma15228004 - 12 Nov 2022

Cited by 5 | Viewed by 1510

Abstract

With the increasing energy crisis and environmental problems, there is an urgent need to seek an efficient renewable energy source, and hydrogen energy is considered one of the most promising energy carriers. Magnesium is considered a promising hydrogen storage material due to its [...] Read more.

With the increasing energy crisis and environmental problems, there is an urgent need to seek an efficient renewable energy source, and hydrogen energy is considered one of the most promising energy carriers. Magnesium is considered a promising hydrogen storage material due to its high hydrogen storage density, abundant resources, and low cost. However, sluggish kinetic performance is one of the bottlenecks hindering its practical application. The kinetic process of hydrogenation/dehydrogenation can be influenced by both external and internal factors, including temperature, pressure, elementary composition, particle size, particle surface states, irregularities in particle structure, and hydrogen diffusion coefficient. The kinetic performance of the MgH₂/Mg system can be effectively improved by more active sites and nucleation centers for hydrogen absorption and desorption. Herein, we briefly review and discuss the experimentally observed nucleation and growth behavior of Mg/MgH₂ during de/hydrogenation of MgH₂/Mg. In particular, the nucleation and growth behavior of MgH₂ during the hydrogenation of Mg is discussed from the aspect of temperature and hydrogen pressure. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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56 pages, 34728 KiB

Open AccessReview

Metal Borohydrides beyond Groups I and II: A Review

by Karina Suárez-Alcántara and Juan Rogelio Tena García

Materials 2021, 14(10), 2561; https://doi.org/10.3390/ma14102561 - 14 May 2021

Cited by 19 | Viewed by 2936

Abstract

This review consists of a compilation of synthesis methods and several properties of borohydrides beyond Groups I and II, i.e., transition metals, main group, lanthanides, and actinides. The reported properties include crystal structure, decomposition temperature, ionic conductivity, photoluminescence, etc., when available. The compiled [...] Read more.

This review consists of a compilation of synthesis methods and several properties of borohydrides beyond Groups I and II, i.e., transition metals, main group, lanthanides, and actinides. The reported properties include crystal structure, decomposition temperature, ionic conductivity, photoluminescence, etc., when available. The compiled properties reflect the rich chemistry and possible borohydrides’ application in areas such as hydrogen storage, electronic devices that require an ionic conductor, catalysis, or photoluminescence. At the end of the review, two short but essential sections are included: a compilation of the decomposition temperature of all reported borohydrides versus the Pauling electronegativity of the cations, and a brief discussion of the possible reactions occurring during diborane emission, including some strategies to reduce this inconvenience, particularly for hydrogen storage purposes. Full article

(This article belongs to the Special Issue Concepts for Improvement of Hydrogen Storage Hydride Materials)

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