Hydrogen Storage Materials Research Articles

Hydrogen molecule adsorption on the MoSe2 and selected-elements (Ru, Os, Rh, Ir, N and P)-doped MoSe2 monolayers as hydrogen storage materials

Adsorption of hydrogen molecules onto the pristine MoSe2 monolayer and N-, P-, Ru-, Rh-, Os- and Ir-doped MoSe2 monolayer surfaces was investigated using periodic DFT method. Adsorption abilities of the pristine and MoSe2 doping derivatives on hydrogen molecule adsorptions are in order: Os–MoSe2 (ΔEads = −2.19 eV) > Ru–MoSe2 (ΔEads = −1.54 eV) > Ir–MoSe2 (ΔEads = −1.08 eV) > Rh–MoSe2 (ΔEads = −0.63 eV) > N–MoSe2 (ΔEads = −0.22 eV) > P–MoSe2 (ΔEads = −0.15 eV) > pristine MoSe2 (ΔEads = −0.06 eV). The adsorption energy of hydrogen onto the Os–MoSe2 surface, which is the most active derivative, stronger than the second most active, the Ru–MoSe2 by 0.65 eV (42%) was found. Nevertheless, all the MoSe2 doping derivatives utilized as hydrogen storage for energy storage purposes were suggested.

Evaluating hydrogen storage potential of NaNbO3-xHx: DFT-based approach

Alternative energy carrier materials are needed since non-renewable energy resources are diminishing at a fast rate. Increasingly, hydrogen storage has gained popularity as a clean energy source. For the first time, NaNbO3-xHx has been explored computationally as a potential material for hydrogen storage using the GGA-PBE approach as implemented in the CASTEP code. Structural, elastic, mechanical, electronic, and optical characteristics have been investigated to evaluate the suitability of the proposed material for hydrogen storage applications. All H-incorporated concentrations are thermodynamical and energetically stable and can be synthesized. Structural parameters vary with varying hydrogen concentrations; however, against each hydrogen concentration, the material maintains cubical geometry. The NaNbO2.7H0.3 show the highest (742.92 GPa) bulk modulus, while NaNbH3 stands with the lowest (52.48 GPa) among all. Standardizing the Poisson ratio reveals a brittle nature except for the X=0.3 composition. With increasing H-incorporation in the structure, the band gap increases (1.624 eV » 2.505 eV) and also causes electronic nature shifting (p-type → n-type); however, the band gap remains indirect over different symmetry points in BZ. Hence, have the potential for numerous optoelectronic applications. Furthermore, optical parameters, dielectric constant, refractive index, extinction coefficient, reflectivity, absorption coefficients, and loss functions are analyzed, which reveal the potential for numerous optoelectronic applications. Hydrogen storage capacity achieved up to 2.48 %, allowing this material to be utilized in energy storage systems.

A novel carbon-induced-porosity mechanism for improved cycling stability of magnesium hydride

MgH2 has been extensively studied as one of the most ideal solid hydrogen storage materials. Nevertheless, rapid capacity decay and sluggish hydrogen storage kinetics hamper its practical application. Herein, a Ni/C nano-catalyst doped MgH2 (MgH2Ni/C) shows an improved hydrogen absorption kinetics with largely reduced activation energy. Particularly, the MgH2Ni/C displays remarkable cycling stability, which maintains a high capacity of 6.01 wt% (98.8 % of initial capacity) even after 50 full hydrogen ab/desorption cycles, while the undoped MgH2 counterpart retains only 85.2 % of its initial capacity. Detailed microstructure characterizations clearly reveal that particle sintering/growth accounts primarily for the deterioration of cycling performance of undoped MgH2. By comparison, MgH2Ni/C can maintain a stable particle size with a growing porous structure during long-term cycling, which effectively increases the specific surface of the particles. A novel carbon-induced-porosity stabilization mechanism is proposed, which can stabilize the proportion of rapid hydrogen absorption process, thus dominating the excellent cycling performance of MgH2Ni/C. This study provides new insights into the cycling stability mechanism of carbon-containing Mg-based hydrogen storage materials, thus promoting their practical applications.

Improved dehydrogenation performance of LiAlH4 doped with BaMnO3

Due to its high gravimetric capacity of hydrogen (10.5 wt.%), LiAlH4 has been regarded as a promising material for solid-state hydrogen storage material for onboard usage. However, high decomposition temperature, poor kinetics and irreversibility retard its application. To counter this problem, various weight percentages of BaMnO3 are introduced into the LiAlH4 system as an additive in this work. As a result, the starting hydrogen release of LiAlH4 was reduced to 109−115 °C and the second desorption temperature occurred at around 134−158 °C, much lower than pure LiAlH4. The isothermal desorption kinetics also proved that faster desorption kinetics can be observed at 90 °C for 80 min. About 2.00−2.60 wt.% of H2 could be desorbed by the composite, whereas only <1.00 wt.% of H2 was desorbed by undoped LiAlH4. Additionally, adding BaMnO3 reduced the activation energies by 30 kJ/mol for the first stages and 34 kJ/mol for the second stages. Based on the X-ray diffraction result, the active species formed of MnO2 and Ba or Ba−containing materials are believed to be responsible for the noticeable enhancement in the desorption properties of LiAlH4.

Enhanced hydrogen adsorption-desorption reversibility found on NiAl alloy: A first-principles study

Improving the hydrogen storage performance of carbon-based materials via transition metals incorporation has been proved experimentally, where control over the hydrogen adsorption kinetics and hydrogen surface diffusion is the key. In this work, we proved theoretically via density functional theory (DFT) how such incorporation promotes better hydrogen storage performance in Ni-based materials supported on graphene, in which static and dynamic behavior of the system were modeled by plane-wave DFT and ab initio molecular dynamics (AIMD), respectively. In addition, the hydrogen storage materials Ni10Al3 and Ni13 supported on graphene, denoted as Ni10Al3/GP and Ni13/GP, are modeled to realize the experimental observation on Ni3Al alloy under high hydrogen pressure. It was found that the Ni10Al3/GP alloy system exhibited better properties in twofold: (1) increased hydrogen adsorption capacity through providing an additional site for H2 molecular adsorption, particularly on the Al atoms, and (2) enhanced hydrogen desorption at ambient conditions observed from reversible H2 adsorption at all coverages with barrierless migration energy. Therefore, the proof from the DFT point-of-view provides valuable insight into exploring other metal alloy systems that can provide additional sites for molecular hydrogen adsorption and improve hydrogen adsorbate mobility.

Electronic metal-support interactions for defect-induced Ru/Co-Sm2O3 mesosphere to achieve efficient NaBH4 hydrolysis activity

Crafting resilient catalysts that promote H2 production through the hydrolysis of hydrogen storage materials like sodium borohydride stands paramount for the impending hydrogen economy. In this study, we propose a versatile metal–organic framework (MOF)-assisted approach to systematically explore the impact of electron-metal support interaction (EMSI) of Ru-modified Co-Sm2O3 (Ru/Co-Sm2O3) on H2 evolution from NaBH4 hydrolysis. Strategic annealing at 800 °C induces cobalt vacancies on the Ru/Co-Sm2O3 surface, optimizing the exposure of active sites and amplifying mass-charge transfer efficiency. Consequently, the defect-enriched Ru/Co-Sm2O3 showcases an impressive hydrogen generation rate (HGR = 0.430 mol min−1 gcatalyst−1) and outstanding cycling resilience, eclipsing the performance of most contemporary catalysts. Experimental findings reveal that Sm can not only adjust the Ru lattice spacing to accommodate more BH4−, but also modulate the Co vacancy concentration, thus bolstering the charge transport and ameliorating the catalyst's electrical conductivity. DFT calculations confirm that the Michaelis-Menten/Eley-Rideal mechanism is more appropriate to explain the hydrolysis of NaBH4.

Physical properties of the XScH3 (X: Ca, and Mg) perovskite hydrides and their hydrogen storage applications

We conducted a comprehensive investigation into the structural, mechanical, electronic, magnetic, thermodynamic, optical, and hydrogen storage properties of the novel XScH3 (X: Ca and Mg) perovskite hydrides by using density functional theory (DFT). Our calculations of the cohesive energy and elastic constants demonstrated that XScH3 compounds exhibit both thermal and mechanical stability. The metallic nature of current materials is based on the investigation of the electronic band structure and total density states. The analysis of Pugh’s ratio (B/G) indicated that these hydrides were ductile materials. Furthermore, it was found that their bonding type was primarily ionic. These substances have been classified as conductors with antiferromagnetic qualities in terms of their magnetic properties. Furthermore, these materials exhibited promising effects on optical properties such as conductivity, absorption, dielectric function, and refractive index. Our predictions revealed that CaScH3 was found to be optically superior hydride. The dynamic stability of these crystals was assessed by analyzing their phonon dispersion curves and by molecular dynamics simulations. Additionally, we studied their thermal properties, including heat capacity, entropy, energy, and free energy, as functions of temperature. Furthermore, our study investigated the hydrogen storage capacity of XScH3 compounds, with CaScH3 and MgScH3, demonstrating hydrogen storage capacities of 3.43 wt.% and 4.18 wt.%, respectively. This study marks the first exploration of XScH3 perovskite hydrides and offers new options for hydrogen storage materials.

Structural-regulation of Laves phase high-entropy alloys to catalytically enhance hydrogen desorption from MgH2

Magnesium hydride (MgH2) is a promising hydrogen storage material, but slow hydrogen desorption kinetics and poor cycling stability still limit its development. Catalytic doping was demonstrated to provide effective solution for it. In this work, we develop novel Zr-based high-entropy alloys (HEAs) catalysts with different Laves phase structures to improve the hydrogen storage in MgH2. It was demonstrated that the catalyst grain size, defect density and lattice distortion have a great influence on the performance of HEAs catalysts. Specially, the C15 type Laves phase HEA exhibits a better catalytic effect than that of C14 type. The introduction of HEAs with "hydrogen pump" effect would shift the rate-limiting step of MgH2 hydrogen desorption from two-dimensional nucleation growth to two-dimension phase boundary migration, which makes it exhibit both great better hydrogen desorption kinetics enhanced by nine times and cycling stability with 92% capacity retention after 30 cycles. This work not only highlights the impact of Laves phase crystal structure regulation on HEAs catalysts, but also provides insights into the design and development of HEAs catalysts to improve the hydrogen storage performance of MgH2.

Materials for green hydrogen production, storage, and conversion

Materials for green hydrogen production, storage, and conversion

Zero-emission hydrogen production by CH4 pyrolysis over Ni/Ferrierite catalyst: Examination of the deactivated catalysts for electrical conductivity and H2 storage properties

An economic route for the generation of hydrogen and utilization of carbon nanofibers (CNFs) was achieved by CH4 cracking over 20 wt%Ni/FER catalyst. The deactivated catalyst demonstrated electrical conductivity and hydrogen storage properties. TEM images displayed open mouths of CNFs and XRF data showed nearly 70% of nickel was recovered from the deactivated catalyst. Impedance studies of the CNFs exhibit prominence as battery electrodes due to their significant conductivity in the presence of nickel. While the hydrogen storage capacity was around 0.151 mmol (gcat)−1 of H2 on the obtained CNFs, it was increased to 0.361 mmol (gcat)−1 upon Ni recovery from the CNFs. A seven-fold increase in the H2 storage of ∼0.862 mmol (gcat)−1 was obtained upon Li doping, exhibiting its distinct property as a hydrogen storage material. The fresh, reduced, used, and deactivated catalysts were characterized by BET-SA, H2-TPR, XRD, Raman spectroscopy, TEM, and H2 pulse chemisorption and Ni/FER was established as an economically viable catalyst for high rates of H2 and CNF production.

Picturing the Gap Between the Performance and US‐DOE’s Hydrogen Storage Target: A Data‐Driven Model for MgH2 Dehydrogenation

Developing solid‐state hydrogen storage materials requires a comprehensive understanding of the dehydrogenation chemistry of a solid‐state hydride. Transition state search and kinetics calculations are essential to understanding and designing high‐performance solid‐state hydrogen storage materials by filling in the knowledge gap that current experiments cannot measure. However, the ab initio analysis of these processes is expensive and time‐consuming. Searching for descriptors to accurately predict the energy barrier is urgently needed, to accelerate the prediction of hydrogen storage material properties and identify the opportunities and challenges. Herein, we develop a data‐driven model to describe and predict the dehydrogenation barriers of a typical solid‐state hydrogen storage material, MgH2, based on the combination of the crystal Hamilton population orbital of Mg‐H bond and the distance between atomic hydrogen. All the parameters in this model can be directly calculated with significantly less computational cost than conventional transition state search, so that the dehydrogenation performance of hydrogen storage materials can be predicted efficiently. Finally, we found that this model leads to excellent agreement with typical experimental measurements reported to date and provides clear design guidelines on how to propel the performance of MgH2 closer to the target set by the United States Department of Energy (US‐DOE).

Picturing the Gap Between the Performance and US-DOE's Hydrogen Storage Target: A Data-Driven Model for MgH2 Dehydrogenation.

Developing solid-state hydrogen storage materials requires a comprehensive understanding of the dehydrogenation chemistry of a solid-state hydride. Transition state search and kinetics calculations are essential to understanding and designing high-performance solid-state hydrogen storage materials by filling in the knowledge gap that current experimentscannot measure. However, the ab initio analysis of these processes is expensive and time-consuming. Searching for descriptors to accurately predict the energy barrier is urgently needed, to accelerate the prediction of hydrogen storage material properties and identify the opportunities and challenges. Herein, we develop a data-driven model to describe and predict the dehydrogenation barriers of a typical solid-state hydrogen storage material, MgH2, based on the combination of the crystal Hamilton population orbital of Mg-H bond and the distance between atomic hydrogen.All the parameters in this model can be directly calculated with significantly less computational cost than conventional transition state search, so that the dehydrogenation performance of hydrogen storage materials can be predicted efficiently. Finally, we found that this model leads to excellent agreement with typical experimental measurements reported to date and provides clear design guidelines on how to propel the performance of MgH2 closer to the target set by the United States Department of Energy (US-DOE).

Experimental Investigation of Phase Equilibria in the Ti-Cr-V System at 1000–1200 °C

Ti-Cr-V-based alloys have been utilized across various domains, including aerospace structural and functional materials and hydrogen storage materials. Investigating the phase relations in the Ti-Cr-V system is significant in supporting the material design for these applications. In the present work, the isothermal sections at 1000, 1100, and 1200 °C for the Ti-Cr-V system were precisely determined through a systematic investigation using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The phase region of Cr2Ti was entirely elucidated for the first time. As the temperature decreased from 1200 to 1000 °C, the V solubility range of Cr2Ti increased from 5.3 wt.% to 10.0 wt.%, while the Ti solubility range essentially remained constant at approximately 31.0–33.9 wt.%. In addition, it was suggested that the stable structure of Cr2Ti was C36 at 1200 °C and C15 at 1000 and 1100 °C. The present work will support thermodynamic re-assessment research.

Sc-Modified C3N4 Nanotubes for High-Capacity Hydrogen Storage: A Theoretical Prediction.

Utilizing hydrogen as a viable substitute for fossil fuels requires the exploration of hydrogen storage materials with high capacity, high quality, and effective reversibility at room temperature. In this study, the stability and capacity for hydrogen storage in the Sc-modified C3N4 nanotube are thoroughly examined through the application of density functional theory (DFT). Our finding indicates that a strong coupling between the Sc-3d orbitals and N-2p orbitals stabilizes the Sc-modified C3N4 nanotube at a high temperature (500 K), and the high migration barrier (5.10 eV) between adjacent Sc atoms prevents the creation of metal clusters. Particularly, it has been found that each Sc-modified C3N4 nanotube is capable of adsorbing up to nine H2 molecules, and the gravimetric hydrogen storage density is calculated to be 7.29 wt%. It reveals an average adsorption energy of -0.20 eV, with an estimated average desorption temperature of 258 K. This shows that a Sc-modified C3N4 nanotube can store hydrogen at low temperatures and harness it at room temperature, which will reduce energy consumption and protect the system from high desorption temperatures. Moreover, charge donation and reverse transfer from the Sc-3d orbital to the H-1s orbital suggest the presence of the Kubas effect between the Sc-modified C3N4 nanotube and H2 molecules. We draw the conclusion that a Sc-modified C3N4 nanotube exhibits exceptional potential as a stable and efficient hydrogen storage substrate.

Amorphous mixed transition metal oxides: A novel catalyst for boosting dehydrogenation of MgH2

Magnesium hydride (MgH2) has been recognized as a promising hydrogen storage material. However, the sluggish hydrogen desorption kinetics is one of the main factors hindering its practical applications. To enhance the dehydrogenation kinetics of MgH2, an amorphous mixed TiO2-ZrO2-V2O5 catalyst is synthesized in this work. After adding the as-synthesized catalyst into MgH2 by ball milling, the dehydrogenation activation energy can be decreased to 65.7 kJ mol−1. Meanwhile, the catalyzed MgH2 shows excellent cycling stability after fifty hydrogen absorption-desorption cycles. The significant improvement of hydrogen desorption kinetics is attributed to the synergistic effect of abundant oxygen vacancies and in situ formed multivalent species in the catalyst. This highlights the importance of designing and synthesizing efficient catalysts for dehydrogenation of MgH2.

Heteroatom sulfur exploration for enhancing MgH2 dehydrogenation: A theoretical and experimental analysis

High operating temperatures and sluggish kinetics constrain the commercial application of magnesium-based hydrogen storage materials. To overcome these drawbacks, this work investigates heteroatom sulfur as a catalyst to improve the dehydrogenation of MgH2 using density functional theory (DFT) and experimental validation. Heteroatom sulfur can influence the dehydrogenation of MgH2 by modulating interfacial carbon-magnesium interactions and substituting surface hydrogen sites. In particular, DFT calculations reveal that sulfur functional groups facilitate charge transfer and significantly reduce the energy barrier of MgH2 by 0.32 eV–1.59 eV. Substitution of sulfur atoms at surface hydrogen sites of MgH2 notably improves dehydrogenation by weakening the Mg–H bond and enabling a sulfur-assisted two-step dehydrogenation mechanism. Experimental results further confirm these theoretical findings. The MgH2/900C–20SO2 sample exhibits that the peak dehydrogenation temperature and the onset dehydrogenation temperature were 19.8 °C and 64 °C lower than that of pure MgH2, and a significant reduction in activation energy from 134.52 kJ mol−1 to 92.12 kJ mol−1. This research provides a comprehensive understanding of the catalytic effects of heteroatom sulfur on MgH2 and offers crucial theoretical and practical insights for the development of more efficient magnesium-based hydrogen storage systems.

Dipole-induced hydrogen bonds enhanced P/O co-doped Lyocell-based porous carbon fiber cloth for hydrogen storage under ambient pressure

Currently, the hydrogen storage application of carbon-based adsorbent materials is mostly implemented under the pressure conditions of 30–300 bar, while there is few targeted studies conducted on the unsaturated adsorption under ambient pressure conditions. Therefore, based on industrialized Lyocell biopolymer fiber precursors and the enhancement effects of dipole-induced hydrogen bonds (DIHB), this work presents a facile construction strategy for P/O co-doped Lyocell-based porous carbon fiber cloth (Ly-ACF-F40). By the technical route of thermal stabilization---sonication assisted phosphoric acid activation---hydrogen bonds introduced by interfacial fluorination, the constructed Ly-ACF-F40 acquires a high specific surface area (1870 m2/g) and total pore volume (1.277 cm3/g), and an excellent hydrogen storage capacity of 3.22 wt% under ambient pressure conditions (77 K, 1 bar). The study directly demonstrated in the experiment that dipole induced hydrogen bonding H(I)-H(II)···F can effectively enhance the atmospheric hydrogen storage density on the basis of other eliminating influencing factors of specific surface area. The simple construction strategy of porous carbon-based materials can provide reference for the research of unsaturated adsorption hydrogen storage materials under ambient pressure conditions, also assist in the application and promotion of low-cost solid hydrogen storage materials.

Understanding the role of transition metal implantation on 2D graphitic carbon nitride for solid-state hydrogen storage: A first principles study

Modifying 2D materials with transition metals (TMs) proves to be an effective approach for enhancing their properties in hydrogen storage. In this article, the hydrogen interaction and adsorption over transition metal (TM) atoms (V, Mn, Fe, and Cu) implanted graphitic carbon nitride (gC3N4) is investigated using density functional theory (DFT). The stability of the TM atom on the gC3N4 surface is studied using binding energy and charge density calculations. The adsorption of H2 on the gC3N4 and TM-implanted gC3N4 surfaces is studied using adsorption energy, density of states (DOS), projected density of states (PDOS), charge density difference, and Lowdin occupancy analysis. The obtained results show that the Fe-gC3N4 system exhibits the highest adsorption energy of −1.025 eV for one H2. It is found that each Fe atom implanted on gC3N4 can stably adsorb up to 8H2 molecules, and the average adsorption energy of the 8H2 molecules is −0.201 eV/H2. In the context of practical applications for these materials, desorption is investigated employing the van't Hoff equation. Our findings affirm that the Fe-gC3N4 system can serve as an efficient material for solid-state hydrogen storage.

Behavior of Lithium Amide Under Argon Plasma.

Alkali and alkaline earth metal amides are a type of functional materials for hydrogen storage, thermal energy storage, ion conduction, and chemical transformations such as ammonia synthesis and decomposition. The thermal chemistry of lithium amide (LiNH2), as a simple but representative alkali or alkaline earth metal amide, has been well studied previously encouraged by its potentials in hydrogen storage. In comparison, little is known about the interaction of plasma and LiNH2. Herein, we report that the plasma treatment of LiNH2 in an Ar flow under ambient temperature and pressure gives rise to distinctly different reaction products and reaction pathway from that of the thermal process. We found that plasma treatment of LiNH2 leads to the formation of Li colloids, N2, and H2 as observed by UV-vis absorption, EPR, and gas products analysis. Inspired by this very unique interaction between plasma and LiNH2, a chemical loop for ammonia decomposition to N2 and H2 mediated by LiNH2 was proposed and demonstrated.

The Density Functional Tight Binding (DFTB) Approach for Investigating Vacancy and Doping in Graphene as Hydrogen Storage

A study on graphene defects for hydrogen storage has been successfully conducted using the Density Functional Tight Binding (DFTB) approach. The research aimed to modify solid materials for hydrogen storage. A 4 × 4 × 1 unit cell was used as the basis, while the supercell used for sampling was enlarged to 40 × 40 × 1. The analyzed data included changes in Density of States (DOS), Fermi level shifts, electronic band structures, formation energy, adsorption energy, and isosurfaces for each graphene orientation. It has been observed that modifying the surface structure of graphene can alter the electronic properties of graphene. This is indicated by shifts in DOS intensity, characterized by increased electronic intensity around the Fermi level total density charge different. The interaction energy between graphene and hydrogen gas has been determined to be -0.0155 eV for H-epoxy graphene, -0.4941 eV for H-monovacancy graphene, and -0.0424 eV for HN-monovacancy graphene. The presence of the vacancy increase the potential to adsorp hydrogen.