Reversible Hydrogen Storage Research Articles

Lithium-grafted Si-doped γ-graphyne as a reversible hydrogen storage host material.

In recent years, hydrogen (H2) has become the most sought-after sustainable energy carrier by virtue of its high energy content and carbon-free emission. The practical implementation of hydrogen as an alternative fuel calls for an efficient and secure storage medium. Within this framework, we have investigated Li-grafted Si-doped γ-graphyne for H2 storage applications by implementing the cutting-edge density functional theory (DFT). A dynamically and thermally stable Si-doped γ-graphyne (SiG) monolayer is functionalized with Li metal atoms that augmented the hydrogen binding strength of the nanolayer by almost three times, owing to the polarization effect of the Li atoms. The Li metal atoms get adsorbed over the monolayer, allowing a binding energy of -2.73 eV that is greater than the Li cohesive energy (-1.63 eV), which eliminates the metal-metal clustering probability. The reliability of the Li-functionalized SiG monolayer (Li8SiG) at elevated temperature has been further substantiated by performing and analyzing ab initio molecular dynamics (AIMD) simulations at 400 K. It is noteworthy that a total of four H2 molecules are held up by each Li atom with an average adsorption energy of -0.32 eV and a maximum gravimetric capacity of 8.48 wt%, which remarkably follows the US-DOE parameters. Partial density of states and Hirshfeld charge analysis are utilized to recognize the interaction channel which reveals the Kubas and Niu-Rao-Jena-like bonding among the metal atoms and loaded hydrogen molecules. The hydrogen occupancy calculated at different temperatures and pressures indicates that hydrogen molecules can be reversibly stored over the Li8SiG system, and it is noted that adsorbed H2 begins to desorb at 280 K, with complete desorption at 400 K and 20 atm (or lower). AIMD simulations are further performed to authenticate the H2 desorption at various temperatures, which agrees well with the occupation number analysis. All the outcomes advocate for efficient reversible hydrogen storage over the proposed host material.

Effect of a mesoporous NiCo2O4 urchin-like structure catalyzed with a surface oxidized LiBH4 system for reversible hydrogen storage applications.

A mesoporous NiCo2O4 urchin-like structure was synthesized by applying a facile hydrothermal method. Different concentrations of NiCo2O4 urchin-like structures were mixed with a surface oxidized LiBH4 system using a wet-impregnation method, followed by heat treatment. The hydrogen storage capacity of LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems was investigated. Typically, hydrogenated LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems desorbed 2.85 wt%, 3.78 wt% and 3.91 wt% of hydrogen, respectively, at the dehydrogenation temperature ranging from room temperature (RT) to 275 °C. Further, the LiBH4 + 75% NiCo2O4 system exhibited better kinetics than other systems and released ∼5.8 wt% of hydrogen at a isothermal dehydrogenation temperature of 250 °C in 60 minutes. Hydrogen binding energies were calculated as 0.28 eV, 0.27 eV and 0.26 eV for LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems, respectively. Moreover, the calculated activation energies of LiBH4 + 25% NiCo2O4, LiBH4 + 50% NiCo2O4 and LiBH4 + 75% NiCo2O4 systems are 17.99 kJ mol-1, 17.03 kJ mol-1 and 16.92 kJ mol-1, respectively. The calculated BET (Brunauer-Emmett-Teller) surface area of NiCo2O4 and LiBH4 + 75% NiCo2O4 systems is 124.05 and 136.62 m2 g-1, respectively. These results showed that hydrogen sorption and desorption properties are significantly increased by the influence of mesoporous structure, lower binding energy and activation energy of LiBH4 + 75% NiCo2O4 system.

Effect of in-situ formation of CeH2.73/CeO2-x and V2O3 on hydrogen storage performance of MgH2

MgH2, one of the most promising lightweight hydrogen storage mediums, has aroused intensive attention due to its outstanding reversible hydrogen storage capacity. However, it suffers from the intrinsic high operating temperature and sluggish kinetics from de-/hydrogenation, hindering its further industrial application. Herein, we successfully synthesized a novel rare earth Ce co-doping with V element forming bimetallic oxide additive, CeVO4 nanoparticles, which exhibits an excellent catalytic effect for enhancing the hydrogen storage performance in MgH2. With an optimization addition of 10 wt% CeVO4, the initial dehydrogenation temperature of the composite decreased from 286 °C to 212 °C. The composite can desorb 6.03 wt% H2 within 6 min at 300 °C and absorb 1.9 wt% H2 within 20 min even at a low temperature of 50 °C. The apparent dehydrogenated activation energy of the composite was obtained as 61.38 ± 3.9 kJ mol−1. The catalyst mechanism analysis revealed that the “hydrogen pumping” effect of the in-situ formed CeH2·73/CeO2-x and V2O3 play a crucial role in boosting the de-/hydrogenation properties of CeVO4-catalyzed MgH2. This work is helpful for further rational designs of novel catalysts in promoting the commercialization of MgH2.

First principles investigation of novel room temperature reversible hydrogen storage media: A Li-decorated 2D B7N5 monolayer

Hydrogen storage media play crucial roles in the realization of sustainable development. However, current materials face challenges in terms of storage capacity and operational conditions. Therefore, the development of novel materials is essential. In this study, we developed a complex structure by decorating Li ions on a two-dimensional (2D) B7N5 substrate, which exhibited multiple porous geometrical configurations, a superlight mass, and a large specific surface ratio, enabling reversible hydrogen storage under room conditions. Theoretical calculations demonstrated that doping with Li ions did not cause structural deformations of the pure 2D B7N5 material. Additionally, charge redistribution coupled with the unique structure of the B7N5 substrate created a regular polarization field that facilitated reversible hydrogen adsorption, with an adsorption energy of −0.23 eV/H2 at 293 K (room temperature) and 101 kPa (standard atmospheric pressure). Meanwhile, the gravimetric capacity reached an impressive 8.77 wt%, surpassing the Department of Energy requirement of 5.5 wt%. We anticipate that the structure and material will inspire further experimental and theoretical research leading to practical applications of hydrogen energy.

Effect of industrial grade raw materials and its associated impurities on first hydrogenation of BCC solid solution alloys

This study explores the effects of using industrial-grade raw materials on the hydrogen storage properties of body-centered cubic (BCC) solid solution alloys. Industrial scrap metals were chosen as the raw material, and the desired alloys were synthesized using a vacuum arc melting furnace. Instead of using pure vanadium (V), different inexpensive industrial substitutes such as low-grade vanadium (V), vanadium nitride (VN), vanadium oxide (VO), and ferrovanadium (FeV) were utilized. The crystal structure, morphology, first hydrogenation, thermodynamics, and cyclability of the prepared alloys were analyzed by using XRD, SEM-EDS, and XPS methods. The crystal structure and morphology analysis revealed multiphase alloys in all the prepared alloys and a Ti rich third phase in the VN sample, which was absent otherwise. The first hydrogenation was performed at room temperature under a hydrogen pressure of 2 MPa without any prior heat treatment. The VO alloy displayed negligible hydrogen absorption during first hydrogenation, while the V, VN, and FeV alloys showed maximum hydrogen storage capacities of 3.49 wt%, 2.47 wt%, and 2.18 wt%, respectively. The presence of oxygen hinders the activation of the VO alloy and requires two activation cycles to activate the sample. A short-term cyclability analysis showed a reversible hydrogen storage capacity of 2 wt%. The change in enthalpy of hydrogen absorption and desorption for V alloy were calculated to be −36.73 ± 8.6 and 57.34 ± 8.3 kJ/mol H2, respectively. One of the prominent advantages of utilizing scrap raw materials was the substantial reduction in overall raw material costs, which saw an impressive 95% decrease when compared to using pure raw materials. These results highlight the economic benefits of incorporating recovered industrial scrap into hydrogen storage alloys.

Mixed Ionic-Electronic Conductivity in Oxygen-Free K2NiF4-Type Hydrides

Hydride-ion conductors and mixed hydride-electronic conductors are promising materials for numerous applications, for example as catalysts, catalyst supports or promoters for hydrogenation reactions, especially ammonia or methanol production. They could also be used in (electro)chemical energy conversion and storage devices such as batteries, fuel cells and reversible hydrogen storage systems. Therefore, there is a major interest in hydride-ion conductors with high conductivity at moderate temperatures.Many presently known hydride-ion conductors are oxyhydrides, of which a large number have the K2NiF4-type structure.[1-5] As oxide ions occupy part of an oxyhydride’s anion sublattice, not all anions participate in hydride-ion transport, thereby potentially limiting the ionic conductivity at moderate temperatures. In this presentation, the synthesis and electrochemical characterization of several different oxygen-free K2NiF4-type structured hydride-ion conductors, such as Rb2CaH4 and Cs2CaH4, will be discussed.By electrochemical analysis, the materials are found to exhibit mixed ionic-electronic conductivity at moderate temperatures. Small instabilities in the conductivity and TPD results which show that the materials release hydrogen gas indicate that the ionic conductivity is related to the presence of hydride-ion vacancies. In addition, computational results show that the measured activation energies are close to the expected values for hydride-ion transport.The total conductivities at 200 °C are around 10-6 S cm-1, a significant portion of this being due to hydride-ion transport. The discovery of mixed hydride-electronic conductivity in these materials opens up new possibilities to explore mixed hydride-electronic conductors in catalysis and low-temperature energy conversion and storage applications. G. Kobayashi et al., Science 2016, 351, 1314-1317.A. Watanabe et al., Electrochemistry 2017, 85, 88-92.Y. Iwasaki et al., J. Mater. Chem. A 2018, 6, 23457-23463.F. Takeiri et al., Inorg. Chem. 2019, 58, 4431-4436.F. Takeiri et al., Nat. Mater. 2022, 21, 325-330. Figure: Illustration of one transport pathway that hydride-ions can take through K2NiF4-type structured materials. The path taken is informed by computational results. Figure 1

First principle studies on triphenylene-hexathiol-based metal-organic framework for hydrogen storage application

We have studied the hydrogen storage capability of the recently synthesized triphenylene-hexathiol based metal-organic framework (MOF) with Fe and Cu metal atoms by using density functional theory and Ab Initio Molecular Dynamics (AIMD) simulations. We found that up to 12 hydrogen molecules were spontaneously adsorbed on the six Fe atoms of the MOF (FeMOF) with adsorption energy of −0.18 eV per H2 molecule, whereas only six H2 molecules were adsorbed on the six Cu atoms of the MOF (CuMOF) with an adsorption energy of −0.17 eV per H2 molecule. Hydrogen molecules were adsorbed on the Fe atom in the FeMOF surface by Kubas interaction. It is observed that the H2 storage capacity of FeMOF did not change due to the substitution of electron donating group, OCH3 on triphenylene molecules. The charge transfer from H2 molecules to the MOF through metal atoms has been confirmed through the density of states and Bader charge analysis. The gravimetric weight percentage of the FeMOF is found to be 1 wt% at room temperature and 1 atm pressure which is considerably higher than that of the studied CuMOF (0.5 wt%). Further, the AIMD results confirmed the structural stability of the studied MOFs. Therefore, the studied FeMOF surface is a suitable material for efficient and reversible hydrogen storage application.

Vanadium-decorated 2D polyaramid material for high-capacity hydrogen storage: Insights from DFT simulations

Herein, systematic computational investigations comprising density functional theory and ab initio molecular dynamics simulations (AIMD) have been conducted to assess the viability of vanadium decoration over the newly synthesized 2D polyaramid material (2DPA-I) as a potentially reversible hydrogen storage substrate for light fuel cell vehicles. The binding energies of V at different positions over 2DPA-I were compared, and the optimum site for V decoration was in the plane of 2DPA-I. The H2 binding ability of V-decorated 2DPA-I was improved over that of pristine 2DPA-I by 185.71 %. A single V atom decorated over 2DPA-I can effectively bind 7 H2 molecules, with a gravimetric H2 storage capacity of ~7.3 wt% and desorption temperature ~330 K at a favourable binding energy window (~−0.4 eV) to facilitate reversible H2 binding. V-decorated 2DPA-I remained stable at elevated temperatures as verified by AIMD simulations, and a substantial energy barrier of ~3 eV exists for the movement of the V atom across the 2DPA-I surface. The interaction of V with 2DPA-I and H2 with V-decorated 2DPA-I proceeds with a charge flow from the V atom towards H2 and 2DPA-I, respectively. The binding energy and charge transfer analysis of the interaction of H2 with V-decorated 2DPA-I indicates possible Kubas interactions. We predict that V-decorated 2DPA-I has immense potential for on-board H2 storage applications in light fuel cell vehicles.

Pristine [formula omitted] monolayer as highly efficient reversible hydrogen storage material under ambient temperature and pressure

The advent of 2D materials has made physisorption-based H2 storage a promising alternative to conventional techniques involving high pressure and cryogenic temperature. However, most of the reported 2D materials require the addition of metal atoms or the application of an electric field to meet the U.S. Department of Energy (DoE) target of 6.5% gravimetric storage capacity for practical usage. Based on density functional theory (DFT), we show 2D BC6N, in its pristine form, demonstrates a storage capacity of 11.11 wt% with a binding energy of 0.139 eV per H2. At 1 atm pressure, the desorption occurs at temperatures above 118.23 °C, making the storage fully reversible at experimentally conceivable temperatures. The study of the desorption temperatures at varied external pressures indicates a broad operational range for commercial usage. Such high uptake capacity at ambient conditions makes pristine 2D BC6N an ideal candidate for metal-free, reversible hydrogen storage.

Lithium functionalized heteroborospherene Si4B32 as a promising hydrogen storage material:A density functional theory study

This study investigates the reversible hydrogen storage performance of Lithium (Li)-functionalized heteroborospherene Si4B32 with density functional theory (DFT) methods. The Si4B32 cage can accommodate a maximum of 6Li atoms without clustering, every Li atom can bind up to 4 H2 molecules. The Li6Si4B32 can still keep its integrity after absorbing 24 H2 molecules. The H2 gravimetric density is 8.922 wt% with 0.220 eV/H2 average hydrogen adsorption energy. The desorption temperature of Li6Si4B32.(H2)24 is 281 K, which indicate H2 molecules can be successfully released at near room temperature. We draw a conclusion that Li-decorated Si4B32 is a potential candidate for reversible hydrogen storage.

Reversible Hydrogen Storage in Solid‐State Reaction Derived Core‐Shell NaBH4@Ni Nanocubes

The method to synthesize high‐capacity complex hydride nanostructures, such as borohydrides, decorated with metallic shells has surfaced as an attractive approach for enabling reversible hydrogen storage. However, the current solvent‐based synthesis methods of such core‐shell nanostructures are limited by solvents/hydrides compatibility issues and the low solubility of the shell precursor in such solvents. Herein, for the first time, an alternative solid‐state method to prepare core‐shell‐like nanostructures is reported. Simply, by mixing and heating vanadium (V)‐doped sodium borohydride (V‐NaBH4) cores and nickelocene (as nickel precursor) at 150 °C, it is possible to decorate V‐NaBH4 with Ni, which shows an improved hydrogen release (≈8 mass% H2) at 350 °C and a net reversible hydrogen capacity of 2 mass%. Detailed structural investigations reveal that the in‐situ formed VxBy and NixBy are responsible for superior hydrogen absorption in the core‐shell material, where these boride species around the shell/interfaces suppress the loss of Na or B and the formation of B12H12 during hydrogen release/uptake. This work opens solvent‐free pathways to design and control the chemical composition of core–shell (boro)hydrides for practical hydrogen storage.

A DFT study on defects and N doping to enhance hydrogen storage in Mg-decorated graphene

In this study, first-principles calculations were used to conduct in-depth studies on multiple key aspects of N-doped defective graphene modified with Mg atoms, including structure, electronic property, thermal stability, as well as hydrogen storage performance and mechanism. The research results show that after the introduction of Mg, N atoms and vacancy defects, pristine graphene transforms from semi-metallic property to metallic property. And the AIMD results indicate excellent thermodynamic stability of the substrate. It can adsorb up to seven H2 molecules, and the adsorption energy values is between −0.15 and −0.21 eV, which is in the stable energy range (-0.15 to −0.60 eV). The hydrogen storage mechanism is mainly attributed to the van der Waals force caused by the polarization of H2 molecules and orbital hybridization between H atoms and the substrate. The calculation of the desorption temperature shows that this substrate can become a potential candidate for reversible hydrogen storage materials at temperatures above 206 K. Compared with graphene decorated with Mg atoms, the introduction of N atoms and vacancy defects significantly improved the hydrogen storage performance.

Potentially reversible hydrogen storage medium: Calcium-decorated boron-doped blue phosphorene

Developing novel hydrogen storage materials with high capacity and efficient reversibility at ambient conditions is crucial to the extensive use of hydrogen energy. In this study, we have systematically investigated the hydrogen storage performances of Ca-decorated boron-doped blue phosphorene (B@BlueP) monolayers by using first-principles calculations. The results show that substitutional boron doping can enhance the interaction between the Ca atom and BlueP and effectively hinder the formation of Ca clusters on the surface of BlueP. The Ca-decorated B@BlueP can store six hydrogen molecules per Ca atom with average adsorption energies of around 0.17–0.24 eV/H2. Electronic structure analysis confirms that both the polarization of hydrogen molecules under the local electrostatic field and the hybridization of Ca-s/d orbitals with H2-σ orbitals contribute to the adsorption of hydrogen molecules in the surrounding of the Ca atom. The decoration of double-sided Ca atoms can lead to a high theoretical gravimetric hydrogen density of 7.29–7.76 wt%, exceeding the storage goal of 5.50 wt% proposed by US-DOE for applications. Furthermore, the practical hydrogen storage capacity at different pressures and temperatures was also studied through thermodynamic analysis, and the storage capacity is calculated to be around 5.50 wt% in practical circumstances (298 K/30 atm and 358 K/5 atm are used as adsorption and desorption conditions, respectively). Hence, the Ca-decorated B@BlueP monolayers have promising potential as reversible hydrogen storage materials under ambient conditions.

Low-temperature hydrogenation of butanal proceeding via keto-enol tautomerization

Hydrogenation of carbonyl-containing compounds to alcohols is a crucial step in various technological processes, including reversible green hydrogen storage. Activation of the highly stable C=O bond, however, is highly challenging and typically proceeds under harsh reaction conditions. Recent theoretical predictions on low-barrier hydrogenation pathway of carbonyl compounds suggest that this step proceeding over a high activation barrier can be overcome in an alternative low barrier process, which comprises two steps: keto-enol tautomerization followed by hydrogenation of the C=C bond in the newly formed enol. The major challenge of this predicted pathway is the low stability of enol species, which would readily convert to ketone if not intentionally stabilized.In this study, we performed atomistic-level investigation on keto-enol tautomerization and low-temperature hydrogenation of butanal over well-defined Pd(111) model catalyst by combination of surface sensitive infrared reflection absorption spectroscopy (IRAS) and molecular beam techniques. Specifically we show that different types of enol species can be formed on the H-containing Pd(111) surface, whose appearance and abundance strongly dependent on the surface temperature. Importantly, the evolution of the partly hydrogenated product of butanal – C-butoxy species attached to Pd via C atom – was detected already at cryogenic temperatures, which points to a possibility of low temperature hydrogenation. A very clear correlation between the abundance of the enol species and the C-butoxy hydrogenated product was detected: the growing concentration of enol species was found to result in the formation of the C-butoxy product. In contrast, strong decrease in the abundance of enol adsorbates lead to full vanishing of the hydrogenation product C-butoxy. With this, we experimentally show a strong link between the population of the enol species and hydrogenation of butanal at cryogenic temperatures. Finally, we discuss the chemical nature of different enol species, which appear to be stabilized on the surface in different ways via hydrogen bonding, and propose the reaction mechanisms of low-barrier butanal hydrogenation that are consistent with all experimental observations.Obtained atomistic-level insights in low-barrier hydrogenation of carbonyl compounds provide important information on the elementary reaction steps of this potentially highly promising class of reactions for green hydrogen storage. Related phenomena can be employed for controlling keto-enol tautomerization and enol stabilization via mutual lateral interactions on functionalized catalytic surfaces for the broad range of aldehydes and ketones to enable their low-barrier hydrogenation.

Composition optimization and hydrogen storage properties of Ti–V–Mn–Fe alloys

Ti–V-based hydrogen storage alloys have garnered interest owing to their salient advantages of reversible hydrogen absorption/desorption at room temperature and excellent kinetic properties. However, the complicated smelting technology of high-purity V metal renders expensive prices, hampering their large-scale production and application. Herein, to overcome this hurdle, abundant and inexpensive Mn and Fe are added to obtain Ti–V–Mn–Fe hydrogen storage alloys. The novel alloy compositions were obtained using a uniform design method. The hydrogen absorption/desorption behaviors of alloys prepared using arc melting technology were analyzed in detail. Systematic investigations show that the activation, kinetics, and thermodynamic properties of alloys are closely correlated with the Ti/(Mn + Fe) ratios. The designed alloy compositions have a multiphase structure with a body-centered cubic (BCC) main phase. The lattice parameters of the BCC phase increase with increasing Ti/(Mn + Fe) ratio, and the large lattice parameters of alloys are beneficial to facilitate the diffusion of hydrogen atoms, resulting in fast kinetics. A reasonable Ti/(Mn + Fe) ratio positively affects the hydrogen storage properties. Among them, the Ti40V40Mn2Fe18 alloy with Ti/(Mn + Fe) = 2 achieved a hydrogen absorption capacity of 3.472 wt% at 298 K and an effective reversible hydrogen storage capacity of 1.485 wt% above 0.1 MPa at 363 K. This study provides a novel insight for designing Ti–V-based alloy compositions via the uniform design method.

Metal-decorated Tri-graphene as a high-performance reversible hydrogen storage medium: A first-principles study

Due to a series of problems caused by the energy crisis, the development of safe and efficient new hydrogen storage materials has become the top priority of current research. In this work, based on the experimental preparation of T‑carbon (Zhang et al. Nat Commun 8, 683 (2017)) material, the [110] surface Tri-graphene (Tri-G) was intercepted. The first-principles method was used to study the hydrogen storage properties of Tri-G and metal-decorated Tri-G. The basic structure and stability of Tri-G are studied systematically, and the electronic properties of Tri-G and metal-decorated Tri-G are calculated respectively. Next, Tri-G is decorated with lithium (Li), sodium (Na), potassium (K), and calcium (Ca). Finally, H2 molecules are attached to each of these bases. The results showed that Tri-G and K@Tri-G could not stably adsorb hydrogen, while Li@Tri-G, Na@Tri-G and Ca@Tri-G could adsorb 24, 14 and 24 hydrogen molecules, and their hydrogen storage rates reached 13.99 wt%, 8.26 wt% and 12.77 wt%, respectively. Moreover, it can be seen that the desorption temperature of H2 is in the range of 255.55 K–281.11 K under the actual conditions of simulated temperature and pressure by Van't Hoff equation, which proves that Li/Na/Ca@Tri-G is an efficient and reversible hydrogen storage material. This study provides theoretical guidance for further expanding the application of carbon-based materials in the field of hydrogen storage.

Development of AB2-type TiZrCrMnFeCoV intermetallic high-entropy alloy for reversible room-temperature hydrogen storage

Intermetallic high-entropy alloys (HEAs) with C14 Laves phase structure have shown promise as hydrogen storage materials due to their ability to maintain the advantages of the AB2-type hydrogen storage alloys while offering the potential for the improvement of hydrogen storage properties through the use of multi-principal elements. However, some intermetallic HEAs are limited in their ability to scale-up production using the low-cost induction melting method and reversible hydrogen storage at room temperature due to their extremely low equilibrium desorption pressure. In this work, intermetallic HEAs with reversible room-temperature hydrogen storage are designed using an empirical model based on calculation of the electronic and geometrical factors. An orthogonal experiment was conducted to optimize the composition and the optimal (Ti1.3Zr0.7)1.1Cr1.1Mn1.8Fe0.3Co0.4V0.4 HEA with a single C14 Laves phase was found to exhibit the best overall hydrogen performance. It can reversibly store 1.84 wt% hydrogen with a relatively low plateau hysteresis factor (0.71) and slope factor (0.89) at a temperature of 15 °C. The dehydrogenation enthalpy and entropy of the optimal HEA were determined to be 35.0 kJ mol−1 and 115.3 J mol−1 K−1, respectively. To reduce the cost of HEAs, FeV80 was employed to replace the V. It was found that the optimal HEA could be successfully scaled-up for production, and our findings demonstrate the potential of intermetallic HEAs for efficient hydrogen storage.

PdRu/SBA15 catalysts for hydrogen storage by reversible N-ethylcarbazole hydrogenation/dehydrogenation reactions

In this work, a stable double complex salt (DCS) on the surface of SBA-15 is constructed by phase transfer-assisted electrostatic adsorption method. DCS was then reduced by glow discharge plasma to obtain SBA-15 loaded PdRu bimetallic catalysts (PdRu/SBA15). The catalysts were characterized by nitrogen adsorption–desorption, TEM, FT-IR, XPS, H2-TPR and ICP-OES. The Pd anion dissolved by phase transfer is precisely adsorbed on the Ru cation, and this unique intimacy of two metals promotes the formation of stable structure. The synergistic effect of the DCS structure and the in-situ reduction of glow discharge plasma makes PdRu/SBA15 have highly dispersed and stable PdRu nanoparticles (NPs). PdRu/SBA15 is suitable for reversible hydrogen storage system. It not only catalyzed N-ethylcarbazole (NEC) hydrogenation efficiently, but also showed enhanced catalytic performance in the dehydrogenation of dodecahydro-N-ethylcarbazole (12H-NEC). The hydrogenation efficiency reached 99.8% for 80 min at 100 °C, H2 pressure of 5 Mpa and the dehydrogenation efficiency reached 100% for 6 h at 180 °C under the action of the same PdRu/SBA15 catalyst. Moreover, the catalytic activity of PdRu/SBA15 catalyst did not decrease obviously after seven cycles in reversible hydrogen storage. The reversible hydrogen storage PdRu catalysts with excellent activity has a very bright prospect in the practical application of fuel cells.

Alloying ratio versus cluster size for reversible hydrogen storage in 3d transition metal doped small Mg clusters: Dispersion corrected DFT study

Alloying ratio versus cluster size for reversible hydrogen storage in 3d transition metal doped small Mg clusters: Dispersion corrected DFT study

Ultrahigh capacity and reversible hydrogen storage media based on Li-decorated T-BN monolayers

Ultrahigh capacity and reversible hydrogen storage media based on Li-decorated T-BN monolayers