High Hydrogen Storage Capacity Research Articles

Production of CO-free H2 through aqueous formic acid dehydrogenation over the α-Mo2C/NC catalyst

Formic acid (FA) is considered a convenient hydrogen carrier with a high hydrogen-storage capacity. Although the non-noble-metal-based catalysts for FA dehydrogenation have made significant progress in recent years, they still face some challenges, such as complex preparation methods and inefficient FA dehydrogenation. Herein, a N-doped carbon (NC) supported α-Mo2C catalyst was successfully synthesized by the one-step pyrolysis strategy and performed excellent catalytic activity for neat FA decomposition while with a low dehydrogenation selectivity. The addition of water significantly improved the FA dehydrogenation selectivity and the α-Mo2C/NC catalyst showed a gas production rate of 224.19 mL/gcat./h and an almost complete dehydrogenation selectivity in the aqueous FA (40 vol.%) at 98 °C. Moreover, no significant deactivation was found during the 60 h stability test under different FA concentrations via this catalyst. The use of NC supported α-Mo2C obtained by one-step pyrolysis as an effective non-noble-metal catalyst and H2O introduction to promote selectivity could provide a novel low-cost­ H2 production strategy from FA.

Catalyst Design and Engineering for CO2-to-Formic Acid Electrosynthesis for a Low-Carbon Economy.

Formic acid (FA) has emerged as a promising candidate for hydrogen energy storage due to its favorable properties such as low toxicity, low flammability, and high volumetric hydrogen storage capacity under ambient conditions. Recent analyses have suggested that FA produced by electrochemical carbon dioxide (CO2) reduction reaction (eCO2RR) using low-carbon electricity exhibits lower fugitive hydrogen (H2) emissions and global warming potential (GWP) during the H2 carrier production, storage and transportation processes compared to those of other alternatives like methanol, methylcyclohexane, and ammonia. eCO2RR to FA can enable industrially relevant current densities without the need for high pressures, high temperatures, or auxiliary hydrogen sources. However, the widespread implementation of eCO2RR to FA is hindered by the requirement for highly stable and selective catalysts. Herein, the aim is to explore and evaluate the potential of catalyst engineering in designing stable and selective nanostructured catalysts that can facilitate economically viable production of FA.

Orientation engineering of magnesium alloy: A review

Mg and its alloys have garnered significant attention due to their exceptional properties, including low density, good damping capacity, biocompatibility, recyclability, and high hydrogen storage capacity. These attributes position them as promising materials for applications in aerospace, transportation, electronics, and biomedical. The wrought Mg alloys, particularly in sheet form, are important materials for manufacturing lightweight structural components. However, their application is often constrained by relatively low room temperature formability. Preferred orientation, also known as texture, plays a crucial role in determining the plasticity and formability of Mg alloys. In this paper, we propose the concept of “orientation engineering”, which involves controlling the crystallographic orientation, thereby enhancing the plasticity and formability of Mg alloys. This review addresses two main aspects: firstly, it systematically explores how preferred orientation influences the plasticity and formability of Mg alloys, providing a foundation for orientation engineering. Secondly, it comprehensively introduces the development of methods to control grain orientation distribution, including alloying, pre-deformation, and asymmetric processing. This review might enhance the scientific understanding of orientation modification in Mg alloys and offer valuable guidance for future research on high-formability Mg alloys.

Intriguing phenomenon of hydrogen molecules occupancy in clathrate hydrate cages: Implications for hydrogen storage

The occupancy of hydrogen in hydrate cages plays a significant role in the hydrogen storage capacity of hydrate-based. Here, we have found two intriguing phenomena of multiple hydrogen molecules occupancy in hydrate cages under relatively mild conditions. We observed the double hydrogen molecule occupancies in the small cages with large-molecule guest substance (1,2-Epoxycyclopentan (ECP)) as the thermodynamic promoter. The discovery illustrates that the stereotypical idea that light guest molecules are always necessary for double hydrogen occupancy in the 512 cages needs to be reconsidered. And we also observed the coexistence of double hydrogen molecules occupancy in the 51264 cages, which is the prerequisite of high hydrogen storage capacity in clathrate hydrates. The discovery obtained in this study can also provide further insight into the mechanism of hydrate formation and significant advances in hydrate-based hydrogen storage technology.

Evaluation and screening of multivariate metal-organic frameworks for hydrogen storage

Multivariate metal-organic frameworks (MTV-MOFs) are characterized by their unique structural feature of incorporating multiple organic linkers and metal ions into a unified framework. This composite construction bestows MTV-MOFs with a broader spectrum of diverse and intricate properties compared to traditional single-component MOFs. In this study, the performance of 560 MTV-MOFs as hydrogen storage adsorbents has been thoroughly investigated. Firstly, the key structural parameters of materials, including density, pore occupied accessible volume, accessible surface area, and porosity were computed. Then, high-throughput Grand Canonical Monte Carlo (GCMC) simulations were employed to calculate hydrogen adsorption capacity of MTV-MOFs under hydrogen pressures of 100 bar at both 77 K and 298 K. Based on simulated results, the deliverable hydrogen capacity of these MTV-MOFs were deduced under both room temperature conditions (298 K, 97.2 bar → 298 K, 5 bar) and low-temperature conditions (77 K, 100 bar → 160 K, 5 bar). Through high-throughput screening, we identified top ten promising MTV-MOFs with the highest hydrogen storage capacity and conducted in-depth studies on their hydrogen adsorption properties. Furthermore, we developed a multivariate linear regression model to quantitatively predict the relationship between hydrogen adsorption capacity and their structural parameters for these MTV-MOFs. The predictions of this model align closely with the outcomes derived from GCMC simulations. The present study highlights the potential of MTV-MOFs as promising candidates for hydrogen storage applications, thereby providing valuable theoretical insights into the exploration of high-capacity hydrogen storage materials.

WO2–N co-doped 2D Carbon nanosheets as multifunctional additives for enhancing the electrochemical hydrogen storage performance of Co2B

Co2B, with its high theoretical hydrogen storage capacity, is a potential solid-state hydrogen storage material. However, its poor cycling life limits its practical application. In this work, in order to improve the cycling stability and reversibility of hydrogen absorption and desorption of Co2B, we propose to use WO2–N–C nanosheets as dopants to mix with Co2B, thereby enhancing its practical performance. Two-dimensional tungsten oxide-nitrogen-carbon (WO2–N–C) nanosheets was syntheized via a liquid-phase approach, using a tungstenate-polydopamine precursor followed by thermal treatment. Subsequently, these WO2–N–C nanosheets were compounded with cobalt boride (Co2B) particles through ball milling at various ratios of 1%, 3%, and 5%, which were confirmed by XRD (X-ray diffraction) and SEM (Scanning Electron Microscope) methods. Employing a comprehensive suite of electrochemical analyses, including corrosion potential measurements, polarization curves, step voltammetry, and electrochemical impedance spectroscopy (EIS), we found that the incorporation of WO2–N–C significantly enhances the corrosion resistance and electrochemical activity of Co2B. Furthermore, cyclic life tests revealed that the WO2–N–C-doped Co2B composites exhibit superior discharge capacities and capacity retention rates compared to pristine Co2B. Notably, the 3% WO2–N–C-doped Co2B composite demonstrated the optimal electrochemical performance, achieving a maximum discharge specific capacity of 555 mAh g−1 and maintaining 82% of its initial capacity after 50 cycles. Our findings underscore the dual role of WO2–N–C in not only augmenting the surface electrochemical activity of Co2B but also providing a protective surface layer, thereby enhancing its overall electrochemical performance.

The design of Mg–Ti–V–Nb–Cr lightweight high entropy alloys for hydrogen storage

In this study, body-centered-cubic Ti24V18Nb6Cr12 high entropy alloy (HEA) is selected as the matrix to design Mg–Ti–V–Nb–Cr lightweight HEAs. Based on first-principles calculations, the hydrogen storage properties of a series of Mg–Ti–V–Nb–Cr HEAs are systematically investigated. The designed Mg-based HEAs are found to be stable after hydrogenation and exhibit high gravimetric hydrogen storage capacities (HSCs). Particularly, the gravimetric HSC of Mg6Ti24V18Cr12 HEA is as high as 4.091 wt%. Besides, the dehydrogenation temperature of the Mg–Ti–V–Nb–Cr HEAs decreases obviously with increasing Mg content, which results from the weakened bonding strength of <M-H> pairs. This study demonstrates that the Mg6Ti24V18Cr12 HEA is a potential candidate for hydrogen storage.

Synergistic Enhancements of Zn-ZIF with Nano Zinc Oxide for Hydrogen adsorption, energy storage, and photocatalytic technologies

Creating the porous Zinc-Zeolitic Imidazolate Framework (Zn-ZIF) using a solvothermal technique addresses the need for advanced materials with distinctive properties and cost-effectiveness in modern applications. The PXRD, SEM, UV-DRS, TEM, and TGA/DTG are used to characterize different concentrations of Zn-ZIF. Zn-ZIF's crystalline structure and phase purity have been verified by PXRD. Using diffuse reflectance spectra, the Kubelka-Monk function determined the band gaps of the Zn-ZIF samples, and scanning electron microscopy revealed a more porous structure. At 77 K and 1 bar, the Zn-ZIF solution with a 2:1 ratio had the highest hydrogen storage capacity (1.71 wt%). The electrochemical behavior of several Zn-ZIF electrodes in a 6 M KOH electrolyte was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments. The Zn-ZIF electrode with a 2:1 ratio exhibits a low charge transfer resistance and a high proton diffusion coefficient (D) of 1.687 × 10−4 cm2 s−1. The characteristics of the 2:1 synthesized Zn-ZIF electrode as a supercapacitor were investigated. Our analysis of the generated Zn-ZIF material's specific capacitance values after 2000 cycles revealed an impressive retention rate of nearly 89 %, with values of 296.6 Fg-1. In addition, we examined the photocatalytic activities of the as-synthesized material by exposing it to ultraviolet light and seeing how it degraded organic dyes such as Cango-Red (CR) dye. With a photocatalytic efficacy of 95.06 % for CR dye, Zn-ZIF (2:1 ratio) is the most effective. These findings should provide new knowledge for researchers interested in developing novel Zn-ZIF materials for photocatalytic, energy storage, and hydrogen storage applications.

First principles investigation for the hydrogen storage properties of novel lithium-based XLiH3 (X=K, Rb) perovskite-type hydrides for advance hydrogen storage system

In this work, the density functional theory is used to investigate the structural, mechanical, electronic, dynamic, thermodynamic, optical and hydrogen storage properties of XLiH3 (X = K, Rb) for the first time. Both KLiH3 and RbLiH3 materials exhibit dynamic, mechanical and thermodynamic stability. The lattice parameters of KLiH3 and RbLiH3 are 3.908 and 4.070 Å, respectively. The investigation of Cauchy pressure, Poisson's ratio and B/G ratio shows that KLiH3 and RbLiH3 are brittle materials. Moreover, the electronic properties of XLiH3 hydrides demonstrate that KLiH3 and RbLiH3 show metallic nature. Optical properties of these compounds are studied and reveal that they have very high refractive indexes and dielectric functions. The thermodynamic properties, including heat capacity, entropy, enthalpy, and free energy of XLiH3, are investigated as well. The hydrogen storage capacities of KLiH3 and RbLiH3 are 5.805 and 3.071 wt%, respectively, confirming that KLiH3 has a high hydrogen storage capacity and is more suitable as a hydrogen storage material. Our study opens up a new-pathway for designing novel hydrogen storage materials.

Rapid hydrogen enclathration and unprecedented tuning phenomenon within superabsorbent polymers

Clathrate hydrate has emerged as a potentially viable storage medium for efficient hydrogen storage, owing to its eco-friendly characteristics and high hydrogen storage capacity. However, it is essential for its practical application to address the challenges posed by harsh thermodynamic formation conditions and slow formation kinetics for hydrogen hydrate. Here, we introduce the utilization of superabsorbent polymers (SAPs) as a dispersion matrix for tetrahydrofuran (THF) solutions to develop a method for rapid hydrogen enclathration. We investigated two distinct synthetic pathways, solution-borne and hydrate-borne routes. We also explored the relationship between hydrogen uptake/storage capacity, varying THF solution concentration within SAPs, and synthetic pathways for binary THF–hydrogen hydrates. The hydrogen storage capacity after 200 min enclathration reaction was relatively low for 1.0 mol% THF cases but significant for 5.56 mol% THF cases in hydrate-borne route (around 20 mmol H2/mol water), highlighting its potential for hydrogen storage material. The spectroscopic analysis revealed that the tuning phenomenon in THF 1.0 mol% hydrate was only observed in the solution-borne route, which facilitated hydrogen enclathration in partially vacant large cages of sII hydrates. It was striking that the tuning phenomenon was also observed in THF 5.56 mol% hydrate synthesized in both solution-borne and hydrate-borne pathways. Through phase equilibria measurements, we confirmed that less than 5.56 mol% of THF participated in forming binary hydrates. The different water and THF absorbability of SAPs resulted in a non-uniform distribution of THF solution within SAPs, causing the unprecedented tuning phenomenon. These findings provide valuable insights into the potential of SAPs for rapid hydrogen enclathration media, emphasizing the importance of understanding synthetic pathways and solution absorption properties for optimized hydrogen storage.

The study of electrochemical hydrogen storage behavior of the MIL-53 (M=Cu, Al, Fe and Cr) framework on the Ag/f-MWCNTs substrate

The goal of this study is to determine the effect of some metal on functionalized multi-walled carbon nanotubes (f-MWCNTs) as well as the impact of central metal on metal–organic frameworks, and the effect of both on the hydrogen storage performance. Another objective of the current study is to modify MOFs and introduce them to the carbonaceous materials. Through this technique which is based on the hydrogen “spillover effect”, the obtained nanocomposite witnessed a significant increase in hydrogen uptakes capacity as compared to the pristine samples. To this end, f-MWCNTs is designed with Cu2+, Ni2+, Co2+ and Ag+. According to the electrochemical hydrogen storage results, the best performance belongs to the Ag/f-MWCNTs which equals 1850 mAhg−1; this figure has increased more than 3.5 times as compared to the f-MWCNTs. Besides, MIL-53 (M=Cu, Al, Fe and Cr) is synthesized as important MOFs owing to their unique structural properties. Among these mentioned MOFs, the MIL-53(Cr) with the highest hydrogen storage capacity which equals 3100 mAhg−1, is selected to be combined with Ag/f-MWCNTs. Eventually, MIL-53(Cr)/Ag/f-MWCNTs nanocomposites, are prepared at ambient pressure and temperature. The hydrogen storage capacity of MIL-53(Cr)/Ag/f-MWCNTs is 4500 mAhg−1, which improved significantly at about 2.4 times higher than Ag/f-MWCNTs sample and 1.4 times higher than MIL-53(Cr) sample.

Studies on hydrogen storage properties of TiVFeNi, (TiVFeNi)95Zr5 and (TiVFeNi)90Zr10 high entropy alloys

The major issues associated with High Entropy Alloys (HEAs) as hydrogen storage material are the activation of these alloys and low storage capacity. The aim of the present investigation is to reduce the activation process and increase the hydrogen storage capacity of TiVFeNi-based HEAs. We investigated the effect of different Zr content on the hydrogen storage properties of TiVFeNi-based HEAs. Four different Ti25V25Fe25Ni25, (TiVFeNi)95Zr5, (TiVFeNi)90Zr10, and (TiVFeNi)80Zr20 HEAs were synthesized through mechanical alloying. The as-synthesized Ti25V25Fe25Ni25 alloy possessed a mixture of bcc and fcc phases. However, the as-synthesized (TiVFeNi)95Zr5 and (TiVFeNi)90Zr10 HEAs possessed bcc and fcc phases with a ZrFe2 intermetallic phase. We found that as the Zr content increases, alloys' hydrogenation behavior, improves due to the better activation process. Among the studied HEAs, in present studies, the highest hydrogen storage capacity is found to be 2.86 wt% at RT with 10 atm of hydrogen pressure for (TiVFeNi)90Zr10 HEA after 15 activation cycles at different temperatures. The high absorption value was found due to the formation of intermetallic ZrFe2, which acts as a bridging entity on the surface of the synthesized bcc and fcc phases. The present study provides a detailed insight into how the presence of the ZrFe2 phase reduces the activation process as well as enhances the hydrogenation properties of TiVFeNi-based HEAs.

High-capacity hydrogen storage in Li-decorated newly synthesized 2D polyaramid: Insights from density functional theory

Using Density Functional Theory, a newly synthesised 2-dimensional polyaramid (2dpa) system decorated with Li is explored for its hydrogen storage capability, and interesting results are obtained. Various sites on 2dpa are studied to ascertain the finest location for Li-decoration. The optimum configuration for hydrogen storage is then achieved by successively adding H2 molecules, till it satisfies the adsorption energy window as prescribed by DoE (0.2–0.7 eV/H2). Li has a good binding energy of −2.78 eV on 2dpa, higher than the cohesive energy for Li and thus prevents any possibilities of clustering. Yet the clustering has been checked by calculating the diffusion energy barrier for the Li atom which came to be around 1.92 eV. The average binding energy for H2 on 2dpa + Li came to be −0.25 eV and the gravimetric weight percent with 3Li on 2dpa and 6H2 molecules attached to each Li comes to be 10.62. Both values meet the conditions set by the US DoE for solid-state hydrogen storage systems. The thermal and dynamic stability of the system has been investigated using Ab initio Molecular Dynamics simulations and computing phonon spectra. Our theoretical results on newly synthesized 2D material may inspire the experimentalist to design a 2dpa-based high-capacity hydrogen storage device.

Suppression effect of CO2 on ignition and combustion of AlH3-nanoparticles: A molecular dynamics study

AlH3 is a high-capacity hydrogen storage material but is prone to explosion. Thermodynamic and structural properties of AlH3-nanoparticles at different CO2 inerting systems from ignition to combustion are studied using ReaxFF-MD method. The influence of CO2 on AlH3-nanoparticles ignition and combustion is investigated by comparing the changes of surface O adsorption rates, particle charge, temperature rise rates and so on. Results indicate that an increase in CO2 is crucial for suppressing AlH3-nanoparticles ignition and combustion by impeding the formation of an Al-rich environment. In contrast to three stages of AlH3-nanoparticles combustion in pure O2 system: surface combustion, slow temperature rise, and self-sustaining combustion, the process of CO2 inerting system is different, with third stage is slow temperature rise at a constant rate. When CO2 concentration reaches to 90%, the dehydrogenation rate reduces by 70.0%, the temperature rise rate decreases by 78.6%, and the ignition delay time reaches 45 ps.

Lithium-modified B3C2P3 monolayer as a promising medium for reversible hydrogen storage

Although two-dimensional (2D) materials have been extensively studied as hydrogen storage media, the search for 2D materials with high hydrogen storage capacity and reversible hydrogen storage properties at room temperature remains challenging. In this context, B3C2P3 monolayer with Li modification is studied systematically by first-principles calculation. We find that Li-modified B3C2P3 monolayer can achieve a high hydrogen storage capacity of 8.99 wt% with an average adsorption energy of −0.23 eV/H2. Three of the H2 molecules are adsorbed around the Li atom, while the fourth H2 molecule is adsorbed above the buckled P atom due to the constricted space around the Li atom. Not only metal Li atoms but also the buckled substrate plays an important role in hydrogen adsorption, indicating that buckled 2D materials are more interesting and promising in hydrogen storage than flat 2D materials. The average desorption temperature (TD) calculated by van't Hoff formula is 293.84 K, which is very close to room temperature. In addition, at room temperature, the structure of hydrogen adsorption is stable at a low pressure of 3.21 MPa, suggesting a broad application prospect of in reversible hydrogen storage.

Preparation of Ni0.6Cu0.4O/NC catalyst and its catalytic performance for hydrogen production from hydrolysis of ammonia borane

Ammonia borane (NH3BH3, AB) is an ideal feedstock with high hydrogen storage capacity. In this paper, nitrogen-containing carbon material (Ni0.6Cu0.4O/NC) catalyst was prepared by high-temperature carbonization of Ni/Cu-ZIF precursor under nitrogen atmosphere. The microstructure as well as the composition of the as-prepared catalyst were characterized. In addition, the catalytic performance of the catalyst was tested under reaction conditions. The results showed that the activation energy (Ea) for hydrolysis of AB over Ni0.6Cu0.4O/NC catalyst was 56.8 kJ/mol with TOF value as high as 1572.2 h–1. The hydrogen production could be approximated as a zero-order reaction with respect to the concentration of AB, and a one-order reaction with respect to the amount of catalyst. The catalyst still maintained good activity after ten cycles, indicating the good stability.

BH6+: Revisiting borohydride cation with negatively charged boron and its possible implications for hydrogen storage

Boron is usually an electropositive element and its hydrides are known for unusual bonding with excellent hydrogen storage capacity. In this paper, we reinvestigated a borohydride cation, BH6+ using the state-of-the-art DFT and ab initio methods. We noticed that its global minimum structure has two covalent 2c-2e bonds and two polar 3c-2e bonds as revealed by the QTAIM analysis. It has indeed negatively charged boron as verified by various population schemes. ADMP simulation-based trajectory analysis of BH6+ for 40 ps confirmed that this cation is kinetically stable over a wide range of temperatures from 100 to 500 K. The superatomic feature of the BH6+ cluster has also been revealed. We also notice that the addition of electrons to BH6+ leads to its dehydrogenation. This may implicate its possible application in high-capacity hydrogen storage.

Magnesium hydrogen storage: Temperature control via particle swarm with nonlinear inertia strategy

Magnesium-based hydrogen storage has garnered significant attention in the field of hydrogen storage due to its notable advantages, including high hydrogen storage capacity and low material cost. However, the relatively high thermodynamic stability of magnesium-based hydrogen storage materials necessitates heating the material to a specific temperature during the hydrogen charging and discharging processes, severely limiting the practical application and further development of this technology.Therefore, this paper aims to design a temperature control system for a magnesium-based solid-state hydrogen storage bottle. The system employs an optimized particle swarm optimization (PSO) algorithm to determine PID parameters, enabling rapid preheating of the hydrogen storage bottle and maintaining a stable operating temperature. Furthermore, by incorporating an appropriate penalty function, the system effectively suppresses temperature overshoot, preventing adverse effects on hydrogen storage performance caused by transient high temperatures, thereby ensuring the safety and stability of the hydrogen storage process.

Characterization of alane (AlH3) thin films grown by atomic layer deposition for hydrogen storage applications

Alane (AlH3) is an increasingly favored material for hydrogen and energy storage. It has demonstrated its potential in various applications, including rocket fuel, explosives, reducing agents, and serving as a viable source of hydrogen for portable fuel cells. In this study, we present the fabrication, morphology and elemental characterization of an AlH3 thin film grown through atomic layer deposition using a dimethylethylamine alane (DMEAA; AlH3N(CH3)2(CH2CH3)) precursor. The AlH3 thin film exhibited a rough surface with a white-like appearance, forming coarse grains as observed via scanning electron microscopy. X-ray diffraction confirmed the presence of AlH3 and it was compared with an aluminum thin film. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed the presence of pure AlH3 under a very thin aluminum oxide surface layer. Additionally, we propose a dissociation reaction mechanism based on the DMEAA precursor. Our work contributes to the advancement of hydrogen storage materials and energy-related applications that necessitate high hydrogen storage capacity and energy efficiency.

Investigation of hydrogen uptake capacity for FAU, MOR, MTW, MWW

In this study, the hydrogen storage properties of various synthetic zeolites, including Zeolite Y (FAU), Mordenite (MOR), ZSM-12 (MTW), and MCM-22 (MWW) are determined at 77 K and atmospheric pressure. The structures of the zeolites are characterized by XRD, ICP-OES, FE-SEM, TGA and N2 adsorption-desorption isotherms. The results show that H-MCM-22 zeolite has the highest hydrogen storage capacity at 1.0 bar with 1.19 wt%, followed by H-MOR zeolite with 1.05 wt%, H–Y zeolite with 0.75 wt% and H-ZSM-12 zeolite with 0.60 wt%. The hydrogen adsorption data on FAU, MOR, MTW, and MWW at 77 K obey the Sips isotherm model. The experimental data show that the ultra-micropore volume of the zeolite is effective in hydrogen adsorption at low-pressure ranges. In addition, increasing the aluminum content of the zeolite increases the hydrogen adsorption capacity of the zeolite at atmospheric pressure. Therefore, zeolites with channel sizes close to the kinetic diameter of a hydrogen molecule, large cage volumes, and high aluminum content are potential candidates for energy storage applications.