High Hydrogen Storage Capacity Research Articles

CoNi alloy catalyst supported on Zr-modified Y2O3 for ammonia decomposition to COx-free hydrogen

The increasing focus on renewable energy has led to the exploration of alternative hydrogen carriers, with NH3 emerging as a promising option due to its ability to overcome storage and transportation challenges, as well as its high hydrogen storage capacity. Co and Ni have been identified as effective catalysts in the decomposition of NH3, owing to their affordability and favorable catalytic properties. In this study, Zr-modified Y2O3 carriers were synthesized using the hydrothermal method. Additionally, mesoporous monometallic and bimetallic catalysts were prepared via the co-precipitation method. The study aimed to investigate the impact of active metal loading, specifically loading Co, Ni, and Co-Ni bimetallic on catalyst activity. The study demonstrated that the CoNi(1:2)/5 %Zr-Y2O3 catalyst exhibited the best catalytic performance and stability, achieving a conversion rate of 90.9 % at 550 °C and GHSV = 9000 mL h-1 gcat-1. The catalytic properties of the catalysts were analyzed using XRD, XPS, SEM, EDX, TEM, and H2-TPR characterization. The results showed that the catalysts prepared using co-precipitation had a large specific surface area and a large number of mesoporous. These catalysts also had CoNi alloy particles on their surface, which resulted in a higher catalytic activity than single metal catalysts due to the synergistic interaction between Co and Ni. The suitable bonding energy also enhanced the stability of the catalysts.

High-performance La–Mg–Ni-based alloys prepared with low cost raw materials

La–Mg–Ni-based hydrogen storage alloys showed good application prospects owing to their high hydrogen storage capacity. However, the poor cycling stability was a key problem. In order to improve the cycling stability, low cost YFe0.85 master alloy was used as raw material to prepare La–Mg–Ni-based La0.8-xYxMg0.2Ni3-0.85xFe0.85x (x = 0.50, 0.55, 0.60) hydrogen storage alloys by powder sintering method. The alloys were mainly composed of PuNi3 phase and MgCu4Sn phase. With the increase of Y and Fe, the cell parameters of PuNi3 phase decreased. Lower mismatch coefficient promoted the cycling stability. As the case of x = 0.60, the capacity retention rate rose up to 95.45%. Aside from the cycling stability, appropriate substitution content contributed to higher capacity and satisfactory kinetics. As the case of x = 0.55, the hydrogen storage capacity reached 1.529 wt%, and hydriding time for the x = 0.60 alloy shrank to 76.7% of that for alloys without Y and Fe at 303 K.

A DFT-D3 investigation on Li, Na, and K decorated C6O6Li6 cluster as a new promising hydrogen storage system

Because of the increasing demand for energy sources, searching for reversible and high-capacity hydrogen storage materials plays a vital role in the extensively utilizing of hydrogen as a clean energy source. In this study, dispersion-corrected density functional theory (DFT-D3) calculations are utilized to examine the possibility of storing H2 molecules on Li, Na, and K alkali metals decorated C6O6Li6 cluster. To evaluate H2 adsorption capability, the adsorption energies, electron density difference iso-surfaces, and charge-transfers are calculated and discussed. The results indicate that a hydrogen molecule is physisorbed on the Li@C6O6Li6, Na@C6O6Li6, and K@C6O6Li6 with average adsorption energies of −0.264, −0.150, and −0.109 eV, respectively. Double-sided alkali metal atoms decoration can lead to the maximum gravimetric density of 15.68, 14.49, and 13.79 wt% for 2Li@C6O6Li6–8H2, 2Na@C6O6Li6–10H2, and 2K@C6O6Li6–12H2 complexes, respectively. Finally, desorption temperatures reveal that the systems can operate as reversible hydrogen storage materials.

The Effect of Y Content on Structural and Sorption Properties of A2B7-Type Phase in the La-Y-Ni-Al-Mn System.

Metal hydrides are an interesting group of chemical compounds, able to store hydrogen in a reversible, compact and safe manner. Among them, A2B7-type intermetallic alloys based on La-Mg-Ni have attracted particular attention due to their high electrochemical hydrogen storage capacity (∼400 mAh/g) and extended cycle life. However, the presence of Mg makes their synthesis via conventional metallurgical routes challenging. Replacing Mg with Y is a viable approach. Herein, we present a systematic study for a series of compounds with a nominal composition of La2-xYxNi6.50Mn0.33Al0.17, x = 0.33, 0.67, 1.00, 1.33, 1.67, focusing on the relationship between the material structural properties and hydrogen sorption performances. The results show that while the hydrogen-induced phase amorphization occurs in the Y-poor samples (x < 1.00) already during the first hydrogen absorption, a higher Y content helps to maintain the material crystallinity during the hydrogenation cycles and increases its H-storage capacity (1.37 wt.% for x = 1.00 vs. 1.60 wt.% for x = 1.67 at 50 °C). Thermal conductivity experiments on the studied compositions indicate the importance of thermal transfer between powder individual particles and/or a measuring instrument.

Performances comparison of adsorption hydrogen storage tanks at a wide temperature and pressure zone

Large-scale application of hydrogen requires safe, reliable and efficient storage technologies. Among the existing hydrogen storage technologies, cryo-compressed hydrogen (CcH2) storage has the advantages of high hydrogen storage density, low energy consumption and no ortho-para hydrogen conversion. But it still needs higher hydrogen storage pressure when reaching higher hydrogen storage density. In order to reduce hydrogen storage pressure and improve storage density, solid adsorption technology is introduced in CcH2. Activated carbon and metal-organic framework materials (MOFs) are employed as adsorbents in this paper. The gravimetric/volumetric hydrogen storage capacities of different adsorption tanks are studied and compared with the hydrogen storage conditions of 1–55 MPa at 77–298 K. The results show that the hydrogen storage density of CcH2 combined with adsorption is higher than that of pure adsorption hydrogen storage, and the storage pressure is lower than that of pure CcH2 under the same hydrogen storage capacity. And the combination of two hydrogen storage technologies can achieve a high hydrogen storage capacity equivalent to that of liquid hydrogen at a lower pressure.

High-capacity hydrogen storage in Li-decorated defective penta-BN2: A DFT-D2 study

The high gravimetric density is important for the application of the materials in hydrogen storage. In this study, a defective penta-BN2 monolayer structure (P-BN2) with Li decoration (Li-C1-P-BN2) is proposed for hydrogen storage. The geometric and electronic properties of Li-C1-P-BN2 are studied. Li atoms could be strongly adsorbed on the defective P-BN2 substrate with an average binding energy of 4.168 eV. The Li atoms are committed to the double-sided adsorption of hydrogen molecules. The adsorption energy and capacity of hydrogen on the P-BN2 are significantly enhanced because of the presence of defects and the Li decoration. A high hydrogen gravimetric density of 9.17 wt% is obtained on the Li-C1-P-BN2. The average adsorption energy of hydrogen on the Li-C1-P-BN2 is −0.139 eV. The hydrogen adsorbed system could maintain stable at 300 K. Therefore, the Li-decorated defective P-BN2 material has great potential in the application of hydrogen storage.

High-symmetry core-shell B12@Ca20C12: A nanocluster-based hydrogen storage material

Since the discovery of C60 fullerene, scientists devoted themselves to searching novel clusters. Among them, the high-symmetry clusters, especially clusters with Ih symmetry, has drawn increasing attention due to their special properties and stabilities. Here, a stable core-shell B12@Ca20C12 with Ih symmetry, which is featured as an icosahedral Ih-B12 centered on the dodecahedron Ca20C12, has been identified using first principles calculations. Its stability has been further confirmed by vibrational frequency analysis with the highest frequency of 834.9 cm−1 and the lowest frequency of 93.7 cm−1. Besides, molecular dynamics simulations indicate that its core-shell structure cannot be destroyed at 325 K under NVT ensembles with Nosé-Hoover chain thermostat. As for the electronic structure, 64 multi-center two-electron bonds were observed throughout the entire core-shell B12@Ca20C12 to keep the cluster maintain its core-shell configuration. More importantly, the core-shell B12@Ca20C12 can storage about 77 H2 molecules by closed-shell interactions with an average adsorption energy of −0.16 eV/H2, resulting in the gravimetric hydrogen density of 12.6 wt%. Based on these results we infer that core-shell B12@Ca20C12 is a potential high-capacity hydrogen storage material and might promote positive experimental efforts in designing excellent hydrogen storage materials.

Effects of Cu doping on the hydrogen storage performance of Ti-Mn-based, AB2-type alloys

The Ti-Mn-based AB2-type hydrogen storage alloy has been widely researched and applied because of their higher hydrogen storage capacity, appropriate service temperature and low cost. However, before this hydrogen storage material becomes a mature technology, the essential issues of activation difficulty and high plateau pressure in hydrogen absorption/desorption process, need to be completely reformed by radical transformation in composition design and structure optimization. This work investigates the microstructure and hydrogen storage performances of Ti0.8Zr0.2Mn0.92Cr0.87Fe0.21 + x Cu (x = 0, 3, 5 and 8 wt%) by vacuum arc melting. Profiting from the excellent hydrogen transfer rate and structure optimization, the Ti0.8Zr0.2Mn0.92Cr0.87Fe0.21 alloys with the increasing of Cu doping result in the unique C14 Laves phase with the increased lattice volume. As a beneficial result, the decrease of the hydrogen absorption platform of Ti0.8Zr0.2Mn0.92Cr0.87Fe0.21 + 8 wt% Cu alloy is accompanied by the increase of the hydrogen desorption platform, thereby reducing the overall hysteresis coefficient of the material. Through Van't Hoff thermodynamic calculation results, it is found that the absolute values of hydrogenation enthalpy and entropy increase with the increasing of Cu doping. It is crucial to doping Cu inside the alloy by the accurate control of stoichiometric proportion and Cu content, which can improve the hydrogen storage performance of the alloy through theoretical analysis and First-principles simulation. This attempt enables new insights into the optimization of the hydrogen storage properties of Ti-Mn-based AB2-type hydrogen storage alloy, which can be generalized to the design of other new hydrogen storage materials.

Optimizing hydrogen ad/desorption of Mg-based hydrides for energy-storage applications

• The typical structures and hydrogen storage mechanism of MgH 2 are briefly introduced. • The research progress of Mg-based hydrides is discussed systematically. • The outlook and remaining challenges upon Mg-based hydrides are delivered in detail. Hydrogen energy is expected to be an “ideal fuel” in the era of decarbonization. The discovery, development, and modification of high-performance hydrogen storage materials are the keys to the future development of solid-state hydrogen storage and hydrogen energy utilization. Magnesium hydride (MgH 2 ), with its high hydrogen storage capacity, abundant natural reserves, and environmental friendliness, has been extensively researched. Herein, we briefly summarize the typical structure and hydrogenation/dehydrogenation reaction mechanism of MgH 2 and provide a comprehensive overview of strategies to effectively tune the thermodynamics and kinetics of Mg-based materials, such as alloying, nanosizing, the introduction of additives, and composite modification. With substantial efforts, great achievements have been achieved, such as lower absorption/desorption temperatures and better cycling stability. Nonetheless, some pivotal issues remain to be addressed, such as unfavorable hydrogenation/dehydrogenation factors, harsh conditions, slow kinetics, incomplete dehydrogenation, low hydrogen purity, expensive catalysts, and a lack of valid exploration of mechanisms in the hydrogenation/dehydrogenation process. Lastly, some future development prospects of MgH 2 in energy-efficient conversion and storage have been presented, including advanced manufacturing ways, stabilization of nanostructures, the introduction of additives combined with structural modification, and utilization of advanced characterization techniques.

Green synthesis and characterization of SnO2, CuO, Fe2O3/activated carbon nanocomposites and their application in electrochemical hydrogen storage

The goal of this study is to produce environmentally friendly nanomaterials that have a high hydrogen storage capacity. The researchers in this study used inexpensive natural bitumen to produce activated carbon (substratum) and a green solution synthesis combustion method to produce CuO, Fe2O3, and SnO2 nanoparticles using a Mint extract as the source material. Metal oxides such as CuO, Fe2O3 and SnO2 are used to increase hydrogen storage capacity and Columbic efficiency. AC and AC/SnO2, AC/CuO, and AC/Fe2O3 nanocomposites have been confirmed via XRD (X-ray diffraction), TEM (transmission electron microscopy), EDX (energy-dispersive X-rays), FT-IR (fourier transform infrared), scanning electron microscope (SEM), and adsorption and desorption analysis of N2 (BET). In terms of discharge capacity, AC/CuO, AC/Fe2O3, and AC/SnO2 display respective capacities of 2250, 2500, and 3600 mAh/g after 20 cycles, respectively. Of all the sample materials, the AC/SnO2 nanocomposite with the highest hydrogen storage capacity has the lowest Columbic efficiency. This implies that a sample with 54% Columbic efficiency, such as AC/CuO nanocomposite, is a more suitable specimen.

Thermochemical method for controlling pore structure to enhance hydrogen storage capacity of biochar

Developing new carbon-based hydrogen storage materials can significantly promote solid-state hydrogen storage technology. Biochar with high hydrogen storage capacity can be prepared by KOH melt activation, which has a high proportion of micropores (96.56%) compared with the porous carbon in the existing literature. Its specific surface area and pore volume are 2801.88 m2/g and 1.44 cm3/g, respectively. The size of the nanopores is affected by the activation ratio, but the temperature has little effect at the low activation ratio. SEM results show that the KOH activation process gradually shifts from the biochar's inside to the outside. A low KOH/char ratio (less than 2:1) can promote the formation of small aromatic rings. Due to its high specific surface area and microporosity, the absolute adsorption capacity of hydrogen in biochar is 2.53 wt% at −196 °C and 1 bar, rising to 5.32 wt% at 50 bar. The hydrogen adsorption process conforms to the Langmuir model. Microporous, mesoporous, and macroporous exhibit different hydrogen adsorption characteristics in various pressure ranges. However, ultramicroporous (<0.7 nm) always plays a decisive role in the hydrogen storage of biochar.

Investigation on the Formation of Rare-Earth Metal Phenoxides via Metathesis

A number of alkali organometallic complexes with suitable thermodynamic properties and high capacity for hydrogen storage have been synthesized; however, few transition metal–organic complexes have been reported for hydrogen storage. Moreover, the synthetic processes of these transition metal–organic complexes via metathesis were not well characterized previously, leading to a lack of understanding of the metathesis reaction. In the present study, yttrium phenoxide and lanthanum phenoxide were synthesized via metathesis of sodium phenoxide with YCl3 and LaCl3, respectively. Quasi in situ NMR, UV-vis, and theoretical calculations were employed to characterize the synthetic processes and the final products. It is revealed that the electron densities of phenoxides in rare-earth phenoxides are lower than in sodium phenoxide due to the stronger Lewis acidity of Y3+ and La3+. The synthetic process may follow a pathway of stepwise formation of dichloride, monochloride, and chloride-free species. Significant decreases in K-band and R-band absorption were observed in UV-vis, which may be due to the weakened conjugation effect between O and the aromatic ring after rare-earth metal substitution. Two molecular structures, i.e., planar and nonplanar, are identified by theoretical calculations for each rare-earth phenoxide. Since these two structures have very close single-point energies, they may coexist in the materials.

Ni0.6Zn0.4O Synthesised via a Solid-State Method for Promoting Hydrogen Sorption from MgH2

Magnesium hydrides (MgH2) have drawn a lot of interest as a promising hydrogen storage material option due to their good reversibility and high hydrogen storage capacity (7.60 wt.%). However, the high hydrogen desorption temperature (more than 400 °C) and slow sorption kinetics of MgH2 are the main obstacles to its practical use. In this research, nickel zinc oxide (Ni0.6Zn0.4O) was synthesized via the solid-state method and doped into MgH2 to overcome the drawbacks of MgH2. The onset desorption temperature of the MgH2-10 wt.% Ni0.6Zn0.4O sample was reduced to 285 °C, 133 °C, and 56 °C lower than that of pure MgH2 and milled MgH2, respectively. Furthermore, at 250 °C, the MgH2-10 wt.% Ni0.6Zn0.4O sample could absorb 6.50 wt.% of H2 and desorbed 2.20 wt.% of H2 at 300 °C within 1 h. With the addition of 10 wt.% of Ni0.6Zn0.4O, the activation energy of MgH2 dropped from 133 kJ/mol to 97 kJ/mol. The morphology of the samples also demonstrated that the particle size is smaller compared with undoped samples. It is believed that in situ forms of NiO, ZnO, and MgO had good catalytic effects on MgH2, significantly reducing the activation energy and onset desorption temperature while improving the sorption kinetics of MgH2.

Development of a new approach for the kinetic modeling of the lithium reactive hydride composite (Li-RHC) for hydrogen storage under desorption conditions

Among some promising candidates for high-capacity energy and hydrogen storage is the Lithium-Boron Reactive Hydride Composite System (Li-RHC: 2 LiH + MgB2/2 LiBH4 + MgH2). This system desorbs hydrogen only at relatively high temperatures and presents a two-step series of reactions occurring in different time scales: first, MgH2 desorbs, followed by LiBH4. Hitherto, the dehydrogenation kinetic behavior of such a system has been described for different temperatures at specific values of operative pressure. However, a comprehensive model representing its dehydrogenation kinetic behavior under different operative conditions has not yet been developed. Herein, the separable variable method is applied to develop a comprehensive kinetic model, including the two-step dehydrogenation series reaction. The MgH2 decomposition is described with the one-dimensional interface-controlled reaction rate Johnson-Mehl-Avrami-Erofeyev-Kholmogorov (JMAEK) with a (Pequilibrium/Poperative) pressure functionality and an Arrhenius temperature dependence activation energy of 63 ± 3 kJ/mol H2. The LiBH4 decomposition is modeled applying the autocatalytic Prout-Tompkins model. A novel approach to describe the Prout-Tompkins t0 parameter as a function of the operative temperature and pressure model is proposed. This second reaction step presented a (Pequilibrium – Poperative/Pequilibrium)2 pressure dependence and an Arrhenius temperature dependence with activation energy 94 ± 13 kJ/mol H2. The proposed approach is experimentally and computationally validated, successfully describing the decomposition kinetic behavior of MgH2 and LiBH4 under three-phase gas, liquid and solid environment and shows good agreement between experimental and modeled curves.

Nitrogen-doped or boron-doped twin T-graphene as advanced and reversible hydrogen storage media

Two-dimensional (2D) carbon-based (C-based) materials can be regarded as potential hydrogen storage media because of their splendid chemical stability and high specific surface area. Recently, a new 2D carbon allotrope twin T-graphene (TTG) with three-atomic layers thick is reported. Motivated by the above exploration, we employed Density Functional Theory (DFT) computational studies to systematically solve twin T-graphene, nitrogen-doped (N-doped) TTG and boron-doped (B-doped) TTG, and evaluate their performance in hydrogen storage at operable thermodynamic conditions. Six hydrogen molecules were adsorbed on the pristine twin T-graphene, and the hydrogen storage capacity was 7.69 wt%. After N doping and B doping, the twin T-graphene both can adsorb eight hydrogen molecules, and the hydrogen storage capacity was increased to 9.88 wt% and 10.06 wt%, respectively. In addition, we found that the hydrogenation/dehydrogenation (desorption) temperature is predicted to be 241 K. The desorption temperature and desorption capacity of H2 under practical conditions further indicate that it can be used as a reversible hydrogen storage media. This study reveals that twin T-graphene, N-doped and B-doped twin T-graphene are promising hydrogen storage materials with splendid desorption temperature, ideal adsorption energy and high hydrogen storage capacity. Meanwhile, this research will expand the application of heteroatom-doped carbon-based materials.

Hydrolysis Kinetics of LiAlH4 at Subzero Temperatures

Hydrolysis of LiAlH4 is a promising path to supply hydrogen at low temperatures due to its high hydrogen storage capacity, where an anti-icing aqueous solution is necessary. However, no hydrolysis kinetics of LiAlH4 with an anti-icing aqueous solution has been reported due to its complexity. Herein, an optimized anti-icing aqueous solution with 27.1 wt% KOH and 30.0% ethylene glycol has been found to obtain full and controllable hydrolysis kinetics of LiAlH4 at −40 to 0 °C. The effects of compactness, mass, and temperature on the hydrolysis of LiAlH4 have been investigated. The LiAlH4 tablet with compactness of 92.7% was demonstrated to obtain a wide constant reaction region (>95%) and be suitable for the hydrolysis reactions. The hydrogen release rates at constant reaction regions were found to follow a linear relationship with the 0.42 power of the mass of a compacted LiAlH4 tablet. A strong temperature-dependent hydrolysis was observed, where the activation energy was deduced from experimental data to be 6.83 ± 0.34 kJ·mol–1. The hydrolysis products of LiAlH4 with the adopted anti-icing aqueous solution after washing with deionized water were found to be the same as those directly with water, indicating no consumption of KOH and ethylene glycol in the reactions. The hydrolysis reaction of LiAlH4 with the adopted solution at −40 to 0 °C has been demonstrated to follow the shrinking core model controlled by liquid film diffusion.

Novel Liquid Organic Hydrogen Carriers with High Hydrogen Performance: NPhCZ/18H-NPhCZ

Exploring the potential liquid organic hydrogen carriers (LOHCs) with high efficiency can promote the advancement of hydrogen storage technology. In this work, a new LOHC member of the carbazole family, perhydro-N-phenylcarbazole (18H-NPhCZ), was first proposed for its high theoretical hydrogen storage capacity (6.9 wt %) and available dehydrogenation reaction enthalpy (ΔrHm(d)⊖ = 51.68 kJ/molH2) based on theoretical calculations. The hydrogenation and dehydrogenation performances were evaluated and exhibited high efficiency in the optimized reaction conditions. The results indicated that 4.74 wt % of H2 was released from 18H-NPhCZ dehydrogenation within 15 min. The combination of experiments and density functional theory (DFT) calculations was employed to investigate the possible intermediates and H2 uptake and release mechanisms. It was found that the elementary reaction from 6H-NPhCZ to NPhCZ was regarded as the rate-limiting step. Furthermore, to balance the storage hydrogen capacity and liquid state at room temperature, a brand-new MIX-LOHC hydrogen storage system (18H-M-B2P1, 6.44 wt %) containing both 18H-NPhCZ and perhydro-dibenzyltoluene (18H-DBT) was successfully proposed as well. It achieved an almost 100% of H2 uptake for 4–6 h and a practical H2 release amount of 6.08 wt % for 10 h. The efficient cycle cohydrogenation and codehydrogenation measurements after 160 h also suggested the stability and reliability of the applications in the hydrogen storage field.

First-principles prediction of structural, electronic and optical properties of alkali metals AM4BN3H10 hydrides

To explore the high storage capacity of hydrogen storage material, the structural feature and hydrogenated mechanism of Li4BN3H10 alkali metal hydrides are studied by using the first-principles calculations. The calculated result predicts that the Li4BN3H10 and Rh4BN3H10 are thermodynamic and dynamical stabilities according to the phonon dispersion and thermodynamic model. Essentially, the hydrogen storage mechanism of AM4BN3H10 hydride mainly depends on the formation of [BH4] group and [NH2] group. Compared to LiBH4, the hybridization between the B atom and H atom in [BH4] group and between the N atom and H atom in [NH2] group can store a lot of hydrogen. However, the dehydrogenation of AM4BN3H10 hydride prefers to [BH4] group rather than the [NH2] group. The narrow band gap is beneficial to hydrogen release in AM4BN3H10 hydride. Therefore, the Rb4BN3H10 has better hydrogen release properties in comparison to the Li4BN3H10 and Na4BN3H10. Therefore, we believe that the AM4BN3H10 hydride is a promising hydrogen storage material with the high hydrogen storage capacity.

Pd-doped HKUST-1 MOFs for enhanced hydrogen storage: effect of hydrogen spillover.

Extensive research has been devoted to developing metal nanoparticle (NP) doped porous materials with large hydrogen storage capacity and high hydrogen release pressure at ambient temperature. The ultra-sound assisted double-solvent approach (DSA) was applied for sample synthesis. In this study, tiny Pd NPs are confined into the pore space of HKUST-1, affording Pd@HKUST-1-DS with minimizing the aggregation of Pd NPs and subsequently the formation of Pd NPs on the external surface of HKUST-1. The experimental data reveal that the obtained Pd NP doped Pd@HKUST-1-DS possessed an outstanding hydrogen storage capacity of 3.68 wt% (and 1.63 wt%) at 77 K and 0.2 MPa H2 (and 298 K and 18 MPa H2), in comparison with pristine HKUST-1 and impregnated Pd/HKUST-1-IM. It is found that the storage capacity variation is not only ascribed to the different textural properties of materials but is also illustrated by the hydrogen spillover induced by different electron transport from Pd to the pores of MOFs (Pd@HKUST-1-DS > Pd/HKUST-1-IM), based on X-ray photoelectron spectroscopy and temperature desorption spectra. Pd@HKUST-1-DS, featuring high specific surface area, uniform Pd NP dispersion and strong interaction of Pd with hydrogen in the confined pore spaces of the support, displays the high hydrogen storage capacity. This work highlights the influence of spillover caused by Pd electron transport on the hydrogen storage capacity of metal NPs/MOFs, which is governed by both physical and chemical adsorption.

Recent advances in sodium borohydride for hydrogen storage

Hydrogen energy is an efficient and renewable clean energy source, and the key issue for its application right moment is the development of hydrogen storage technology with high density and safety. Among many available hydrogen storage materials, metal complex hydrides with the advantages of high hydrogen storage capacity and good safety, are promising for future applications. However, high-capacity hydrogen storage composites suffer from disadvantages such as high hydrogen release temperature and poor reversibility, which severely limit their application. This paper provides a detailed summary of existing approaches to improve the kinetic and thermodynamic properties of NaBH4 for hydrogen storage, including the addition of catalysts, the incorporation of appropriate reactants and the preparation of nanoscale NaBH4, as well as an outlook on the future direction of pyrolysis.