Nanomaterials For Hydrogen Storage Research Articles

Exploring Nanomaterials for Hydrogen Storage: Advances, Challenges, and Perspectives.

Hydrogen energy heralded for its environmentally friendly, renewable, efficient, and cost-effective attributes, stands poised as the primary alternative to fossil fuels in the future. Despite its great potential, the low volumetric density presents a formidable challenge in hydrogen storage. Addressing this challenge necessitates exploring effective storage techniques for a sustainable hydrogen economy. Solid-state hydrogen storage in nanomaterials (physically or chemically) holds promise for achieving large-scale hydrogen storage applications. Such approaches offer benefits, including safety, compactness, lightness, reversibility, and efficient generation of pure hydrogen fuel under mild conditions. This article presents solid-state nanomaterials, specifically nanoporous carbons (activated carbon, carbon fibers), metal-organic frameworks, covalently connected frameworks, nanoporous organic polymers, and nanoscale metal hydrides. Furthermore, new developments in hydrogen fuel cell technology for stationary and mobile applications have been demonstrated. The review outlines significant advancements thus far, identifies key barriers to practical implementation, and presents a perspective for future sustainable energy research. It concludes with recommendations to enhance hydrogen storage performance for cost-effective and long-lasting utilization.

Structural evolution and hydrogen storage properties of ScHn− (n = 10–20) clusters

An unbiased Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method combined with density functional theory (DFT) study was adopted to identify the ground state ScHn− (n = 10–20) isomers. We have performed a series of investigation of electronic properties, structural evolution, hydrogen storage properties of ScHn− (n = 10–20) clusters. Using time-dependent (TD-) DFT, the photoelectron spectra (PES) of the low-lying structures of ScHn− clusters have been simulated. The adsorption energies of ScHn− (n = 10–20) clusters are found in 2.52 eV-2.65 eV, and all hydrogen atoms are adsorbed on the Sc atom. Studied on the molecular orbitals and chemical bonds of the ScH12− cluster, it is found that the ScH12− cluster are mainly the interaction between the 3d atom orbital of Sc and the 1s atom orbital of H. The present study aims at novel nanomaterials for hydrogen storage.

Theoretical study on geometric structures and hydrogen storage in anionic CeH[formula omitted] ([formula omitted] = 2–20) nanoclusters

The geometric structures of anionic CeHn− (n = 2–20) clusters are obtained using crystal structure analysis by particle swarm Optimization(CALYPSO) and density functional theory(DFT). The SDD basis set for Ce atom and the all electron 6-311G ＋ ＋ (D, P) basis set for H atom are set respectively, and the lower-energy isomers in each size for CeHn− (n = 2–20) clusters are re-optimized at the B3LYP level. The photoelectron spectroscopy(PES) for the global minimum of anionic CeHn− (n = 2–20) clusters have been simulated using the Time-Dependent Density Function Theory(TD-DFT) method to determine the authenticity of all the lowest-energy structures obtained. The anionic CeH10− cluster with C2v point group symmetry and an excellent hydrogen storage capacity of 6.7 wt% has been discovered. Chemical bond analysis shows that the internal stability of anionic CeH10− cluster is primarily affected by the interaction between Ce 4f orbital and H 1s orbital, which is formed σ bond at the larger HLG of 4.78 eV. Furthermore, anionic CeH10− cluster has high hydrogen storage capacity, large adsorption energy and good stability, which is expected to be a new nanometer hydrogen storage material. The present work provides guidance for the future synthesis and design of new rare earth(RE) hydrogen storage nanomaterials.

Theoretical design of a new hydrogen storage based on the decorated phosphorene nanosheet by alkali metals

In this study, the ability of decorated phosphorene with Alkali metals to absorb H2 was investigated using density functional theory dispersion corrected calculations and ab initio molecular dynamics (AIMD) simulations. The results show that the Li-phosphorene complex shows greater stability than other decorated phosphorene nanosheets with alkali metals. Because of the significant dispersion interactions (−0.29 eV) with the phosphorene surface, Li-phosphorene is the most stable decorate, demonstrating the importance of dispersion interactions as the driving force in decorate formation. The analysis of non-covalent interactions revealed that van der Waals interactions between the surface and alkali metals play an important role in the stability of the phosphorene-metals decorated and confirmed the H2 physisorption on the phosphorene surface. Donor-acceptor (DA) interaction analysis confirmed that the origin of this sensitivity could be attributed to molecular orbital interactions between these metals and the phosphorene surface, so Li-phosphorene is the most stable decorated compound due to strong DA interaction (41.9 kcal mol−1). Overall, the results show that the decorated phosphorene with Li is a promising candidate for developing new nanomaterials for hydrogen storage. Moreover, AIMD results reveal that the capacity trend of the designed systems based on alkali metal-phosphorene for hydrogen adsorption is as follows: Li > Na > K > Rb > Cs. It is well worth mentioning that each Li atom can adsorb roughly three hydrogen molecules on the surface of the phosphorene nanosheet.

Enhanced reversible hydrogen storage performance of light metal-decorated boron-doped siligene: A DFT study

The use of nanomaterials for hydrogen storage could play a very important role in the large-scale utilization of hydrogen as an energy source. However, nowadays several potential hydrogen storage nanomaterials do not have a large gravimetric density and stability at room temperature. In this work, we have investigated the hydrogen storage performances of Na-, K- and Ca-decorated B-doped siligene monolayer (BSiGeML) using density functional theory calculations. The results show that boron doping improves the interaction between the metal adatom and the siligene monolayer (SiGeML). The K- and Ca-decorated BSiGeMLs can bind up to seven H2 molecules per metal adatom, whereas Na-decorated BSiGeML only adsorb four H2 molecules per adsorption site. The effect of temperature and pressure on the hydrogen storage capacity of BSiGeMLs was also evaluated. At room temperature, all the H2 molecules adsorbed on Na-, and Ca-decorated BSiGeML are stable at mild pressure. The metal decoration of both sides of BSiGeML may lead to hydrogen gravimetric densities exceeding the target of 5.5 wt% proposed by DOE for the year 2025. K- and Ca-decorated BSiGeML could be efficient hydrogen molecular storage media compared to undoped SiGeML and other 2D pristine materials.

Anionic La[formula omitted]: A nanocluster-based hydrogen storage material

The geometric structures of anionic LaHn−(n=2−20) clusters are predicted by CALYPSO cluster structural search method and first-principles calculations. The low-lying isomers for each size of LaHn−(n=2−20) clusters are further reoptimized at B3LYP level by setting all-electron 6-311G + + (d, p) basis set for H atoms and SDD basis set for La atom, respectively. The photoelectron spectroscopy (PES) of the ground-state structures are simulated by time-dependent DFT (TD-DFT) method. It is found that the anionic LaH8− cluster with D2d symmetry is the most stable structure and its hydrogen storage capacity arrives at 5.4 wt%. The stability of anionic LaH8− cluster is mainly affected by the strong interaction between H 1s orbital and La 5d orbital. The present results provide insights into the further exploration and discovery of novel rare-earth based hydrogen storage nanomaterials.

A single palladium atom immerses in magnesium clusters: PdMg n (n = 2–20) clusters DFT study

The structure, stability, charge transfer, and chemical bonding properties of palladium-doped magnesium clusters, PdMg n (n = 2–20), are comprehensively researched by CALYPSO software within first-principles DFT computations. It is shown that the cluster structure evolved from a tetrahedral-based structure to a cage-like structure, and interestingly, the single Pd atom always immerses in the Mg n clusters except for PdMg2 and PdMg3. Stability studies indicate that PdMg4, PdMg7, PdMg10, and PdMg15 clusters have relative robust stability and can be identified as ‘magic’ clusters. Most importantly, chemical bonding studies reveal that Pd–Mg is always non-covalent bond (closed-shell) interaction in all PdMg n (n = 2–20) clusters, and PdMg6 and PdMg7 are the critical sizes at which Mg–Mg covalent interactions occur. The geometric structure database of transition metal-doped Mg clusters will be enriched by this study, and it also provides, at least theoretically, new members of cage-like structures for magnesium-based hydrogen storage nanomaterials.

Anionic LaH - 8: A Nanocluster-Based Hydrogen Storage Material

The geometric structures of anionic LaH-n (n=2-20) clusters are predicted by CALYPSO cluster structural search method and first-principles calculations. The low-lying isomers for each size of LaH-n (n=2-20) clusters are further reoptimized at B3LYP level by setting all-electron 6-311G++(d, p) basis set for H atoms and SDD basis set for La atom, respectively. The photoelectron spectroscopy (PES) of the ground-state structures are simulated by time-dependent DFT (TD-DFT) method. It is found that the anionic LaH-8 cluster with D2d symmetry is the most stable structure and its hydrogen storage capacity arrives at 5.4 wt%. The stability of anionic LaH-8 cluster is mainly affected by the strong interaction between H 1s orbital and La 5d orbital. The present results provide insights into the further exploration and discovery of novel rare-earth based hydrogen storage nanomaterials.

MgScH15: A highly stable cluster for hydrogen storage

Mg-Sc-H systems exhibit superior stability and high hydrogen storage capacity among the large class of magnesium-based hydrogen storage materials, but the underlying mechanisms for their outstanding hydrogen storage properties remain largely unexplored and require further investigation. Here, we have performed a comprehensive investigation on the structural evolution of MgScHn (n = 10–20) clusters by unbiased Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method combined with density functional theory (DFT) optimizations at the B3PW91/6-311 + G(d) level. Our results show that the MgScH15 cluster with Cs symmetry is found to be the most stable cluster with good hydrogen storage capacity of 17.8 wt% due to the strong interaction among the 1s orbitals of the H atoms, the 2p orbitals of the Mg atom and the 3d orbitals of the Sc atom. The present findings are promising for further exploring novel hydrogen storage nanomaterials.

Design of Nanomaterials for Hydrogen Storage

The interaction of hydrogen with solids and the mechanisms of hydride formation experience significant changes in nanomaterials due to a number of structural features. This review aims at illustrating the design principles that have recently inspired the development of new nanomaterials for hydrogen storage. After a general discussion about the influence of nanomaterials’ microstructure on their hydrogen sorption properties, several scientific cases and hot topics are illustrated surveying various classes of materials. These include bulk-like nanomaterials processed by mechanochemical routes, thin films and multilayers, nano-objects with composite architectures such as core–shell or composite nanoparticles, and nanoparticles on porous or graphene-like supports. Finally, selected examples of recent in situ studies of metal–hydride transformation mechanisms using microscopy and spectroscopy techniques are highlighted.

Hybrid Veil-Like Co(OH)2/rGO Nanocomposites Towards Electrochemical Hydrogen Storage Properties

The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today’s development of a hydrogen economy. As a new type hydrogen storage material, Co(OH)2/rGO nanocomposites were successfully obtained through a facile method in this study. Through the measurements of X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry and galvanostatic charge/discharge, it indicated that Co(OH)2/rGO nanocomposites showed a veil-like microstructure, consisting of interlaced nanorods with a diameter of 4–8[Formula: see text]nm on rGO nanosheets. The hydrogen storage capacity was up to 400[Formula: see text]mAh/g at room temperature, higher than those of graphene and Co(OH)2.

Direct observation of site-selective hydrogenation and spin-polarization in hydrogenated hexagonal boron nitride on Ni(111).

We report the structural analysis and spin-dependent band structure of hydrogenated boron nitride adsorbed on Ni(111). The atomic displacement studied by using the normal incidence X-ray standing wave (NIXSW) technique supports the H-B(fcc):N(top) model, in which hydrogen atoms are site-selectively chemisorbed on boron atoms and N atoms remain on top of Ni atoms. The distance between the Ni plane and nitrogen plane did not change after hydrogenation, which implies that the interaction between Ni and N is 3d-π orbital mixing (donation and back-donation) even after hydrogenation of boron. The remaining π* peaks in near-edge X-ray absorption fine structure (NEXAFS) spectra are a manifestation of the rehybridization of sp2 into sp3 states, which is consistent with the N-B-N bonding angle derived from NIXSW measurement. The SPMDS measurement revealed the spin asymmetry appearing on hydrogenated h-BN, which was originated from a π related orbital with back donation from the Ni 3d state. Even though the atomic displacement is reproduced by the density functional theory (DFT) calculation with the H-B(fcc):N(top) model, the experimental spin-dependent band structure was not reproduced by DFT possibly due to the self-interaction error (SIE). These results reinforce the site-selective hydrogenation of boron and pave the way for efficient design of BN nanomaterials for hydrogen storage.

Composition and size dependence of hydrogen interaction with carbon supported bulk-immiscible Pd–Rh nanoalloys

In-depth clarification of hydrogen interaction with noble metal nanoparticles and nanoalloys is essential for further development and design of efficient catalysts and hydrogen storage nanomaterials. This issue becomes even more challenging for nanoalloys of bulk-immiscible metals. The hydrogen interaction with bulk-immiscible Pd–Rh nanoalloys (3–6 nm) supported on mesoporous carbon is studied by both laboratory and large scale facility techniques. X-ray diffraction (XRD) reveals a single phase fcc structure for all nanoparticles confirming the formation of nanoalloys in the whole composition range. In situ extended x-ray absorption fine structure (EXAFS) experiments suggest segregated local structures into Pd-rich surface and Rh-rich core coexisting within the nanoparticles. Hydrogen sorption can be tuned by chemical composition: Pd-rich nanoparticles form a hydride phase, whereas Rh-rich phases do not absorb hydrogen under ambient temperature and pressure conditions. The thermodynamics of hydride formation can be tailored by the composition without affecting hydrogen capacity at full hydrogenation. Furthermore, for hydrogen absorbing nanoalloys, in situ EXAFS reveals a preferential occupation of hydrogen for the interstitial sites around Pd atoms. To our knowledge, this is the first study providing insights into the hydrogen interaction mechanism with Pd–Rh nanoalloys that can guide the design of catalysts for hydrogenation reactions and the development of nanomaterials for hydrogen storage.

Hydrogen adsorption on sulphur-doped SiC nanotubes

Hydrogen (H2) is an energy carrier and clean fuel that can be used for a broad range of applications that include fuel cell vehicles. Therefore, development of materials for hydrogen storage is demanded. Nanotubes, in this context, are appropriate materials. Recently, silicon carbide nanotube (SiCNTs) have been predicted as potential nanomaterials for hydrogen storage, and atomic doping into the nanotubes improves the H2 adsorption. Here, we report H2 adsorption properties of sulphur-doped (S-doped) SiCNTs using first-principles calculations based on density functional theory. The H2 adsorption properties are investigated by calculations of energy band structures, density of states (DOS), adsorption energy and Mulliken charge population analysis. Our findings show that, compared to the intrinsic SiCNT, S-doped SiCNT is more sensitive to H2 adsorption. H2 gas adsorption on S-doped C-sites of SiCNT brings about significant modulation of the electronic structure of the nanotube, which results in charge transfer from the nanotube to the gas, and dipole–dipole interactions cause chemisorptions of hydrogen. However, in the case of H2 gas adsorption on S-doped Si-sites of the nanotube, lesser charge transfer from the nanotube to the gas results in physisorptions of the gas. The efficient hydrogen sensing properties of S-doped SiCNTs, studied here, may have potential for its practical realization for hydrogen storage application.

Shape-Dependent Interactions of Palladium Nanocrystals with Hydrogen.

Elucidation of the nature of hydrogen interactions with palladium nanoparticles is expected to play an important role in the development of new catalysts and hydrogen-storage nanomaterials. A facile scaled-up synthesis of uniformly sized single-crystalline palladium nanoparticles with various shapes, including regular nanocubes, nanocubes with protruded edges, rhombic dodecahedra, and branched nanoparticles, all stabilized with a mesoporous silica shell is developed. Interaction of hydrogen with these nanoparticles is studied by using temperature-programmed desorption technique and by performing density functional theory modeling. It is found that due to favorable arrangement of Pd atoms on their surface, rhombic dodecahedral palladium nanoparticles enclosed by {110} planes release a larger volume of hydrogen and have a lower desorption energy than palladium nanocubes and branched nanoparticles. These results underline the important role of {110} surfaces in palladium nanoparticles in their interaction with hydrogen. This work provides insight into the mechanism of catalysis of hydrogenation/dehydrogenation reactions by palladium nanoparticles with different shapes.

Recent progress on Kubas-type hydrogen-storage nanomaterials: from theories to experiments

Transition-metal (TM) atoms are known to form TM-H2 complexes, which are collectively called Kubas dihydrogen complexes. The TM-H2 complexes are formed through the hybridization of the TM d orbitals with the H2 σ and σ* orbitals. The adsorption energy of H2 molecules in the TM-H2 complexes is usually within the range of energy required for reversible H2 storage at room temperature and ambient pressure (−0.4 ~ −0.2 eV/H2). Thus, TM-H2 complexes have been investigated as potential Kubas-type hydrogen-storage materials. Recently, TM-decorated nanomaterials have attracted much attention because of their promising high capacity and reversibility as Kubas-type hydrogen-storage materials. The hydrogen storage capacity of TM-decorated nanomaterials is expected to be as large as ~9 wt%, which is suitable for certain vehicular applications. However, in the TM-decorated nanostructures, the TM atoms prefer to form clusters because of the large cohesive energy (approximately 4 eV), which leads to a significant reduction in the hydrogen-storage capacity. On the other hand, Ca atoms can form complexes with H2 molecules via Kubas-like interactions. Ca atoms attached to nanomaterials have been reported to be able to adsorb as many H2 molecules as TM atoms. Ca atoms tend to cluster less because of the small cohesive energy of bulk Ca (1.83 eV), which is much smaller than those of bulk TMs. These observations suggest thatKubas interactions can occur in d orbital-free elements, thereby making Ca a more suitable element for attracting H2 in hydrogen-storage materials. Recently, Kubas-type TM-based, hydrogen- stor ge materials were experimentally synthesized, and the Kubas-type interactions were measured to be stronger than the van der Waals interactions. In this review, the recent progress of Kubas-type hydrogen- storage materials will be discussed from both theoretical and experimental viewpoints.

Magnesium-based hydrogen storage nanomaterials prepared by high energy reactive ball milling in hydrogen at the presence of mixed titanium–iron oxide

An experimental study was undertaken on the preparation, by High Energy Reactive Ball Milling in Hydrogen (HRBM), of hydrogen storage materials on the basis of Mg mixed with FeTiO3, and their further characterisation (SEM, TEM, XRD, volumetric H2 absorption studies, TDS). It was shown that the addition of ⩾5wt.% of FeTiO3 dramatically improves H absorption in Mg and reduces the temperature of further H desorption. Subsequent addition of carbon, including Graphite (G), Activated Carbon (AC) and Multi-Wall Carbon Nanotubes (MWCNT) results in some slowing of the H absorption down but significantly improves re-hydrogenation performances of the material, which in time is able to re-absorb about 5wt.% H in less than 5–7min (15bar H2/250°C). These improvements were associated with the reduction of FeTiO3 to yield nanoparticles of Fe and TiFe(Hx).

Exploring several different routes to produce Mg- based nanomaterials for Hydrogen storage

Severe mechanical processing routes based on high-energy ball milling (HEBM) or severe plastic deformation (SPD) can be used to produce Mg nanomaterials for hydrogen storage applications. In the last few years, we have been exploring in our research group different SPD processing routes in Mg systems to achieve good activation (first hydrogenation) and fast H-absorption/desorption kinetics, combined with enhanced air resistance. In this paper, we compare SPD techniques applied to Mg with HEBM applied to MgH2. Both advanced – melt spinning (MS), high-pressure torsion (HPT) – and more conventional – cold rolling (CR), cold forging (CF)- techniques are evaluated as means of production of bulk samples with very refined microstructures and controlled textures. In the best SPD processing conditions, attractive H-absorption/desorption kinetic properties are obtained, which are comparable to the ones of MgH2 milled powders, even if the needed temperatures are higher – 350°C compared to 300°C.CR and CF stand out as the processes with higher potential for industrial application, considering the level of the attained hydrogen storage properties, its simplicity and low cost.

Mechanical Ball-Milling Preparation of Fullerene/Cobalt Core/Shell Nanocomposites with High Electrochemical Hydrogen Storage Ability

The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today's development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60's surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co-C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co-Hx reaction is the dominant cycle process.

Synthesis of Carbon-Based Nano Materials for Hydrogen Storage

The aim of this study was to synthesize the carbon-based nanomaterials and determine their hydrogen storage capacities. Carbon nanotubes (CNTs) were first synthesized by chemical vapor deposition (CVD) of acetylene (C2H2) on a magnesium oxide (MgO) powder impregnated with an iron nitrate (Fe(NO3)3·9H2O) solution. The synthesis parameters were selected as the synthesis temperatures of 500 and 800°C, the iron content in the precursor of 5% and the synthesis time of 30 minutes. The synthesized material was purified by using HCl at 75°C for 15 hours. After synthesis of CNTs, the polyaniline-doped H3BO3 and BF3 and composites were prepared by coagulation method. The synthesized CNTs and composites were characterized by transmission electron microscopy, FT-IR spectroscopy, Raman spectroscopy and thermogravimetric analyzer. The BET specific surface areas were obtained from the nitrogen adsorption isotherms at -196°C. The hydrogen storage capacities of these carbonaceous materials were measured using volumetric method. It was found that the hydrogen adsorption capacities were changed in the range between 0.44 and 3.67wt% at the liquid nitrogen temperature and gas pressure up to 100 bar.