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Safe and effective storage of hydrogen fuel is a step toward a hydrogen economy. As a model storage media, magnesium hydride (MgH2) experiences sluggish dehydrogenation dynamics, although its stora...

The oxygen evolution reaction is of great significance to the production of hydrogen from high efficiency electrolytic water, hydrogen oxygen fuel cell and other energy conversion devices, but there are many challenges such as high cost, low efficiency and poor stability of catalysts. Among non-precious metal catalysts, oxide has its unique advantages. We used overdoping strategy to prepare two-phase oxide electrocatalyst SrCo

The IRS Form 990 provides a rich set of financial and nonfinancial information about nonprofit organizations. Historically, these returns were available to researchers in PDF format, or partial data were available through information aggregators. Beginning in 2011, the forms were e-filed in an XML format, and those files are made available to the public at no monetary cost. To date over 2.6 million of these returns have been filed and are currently available online. This study uses the design science paradigm to describe the process of accessing the forms from AWS (Amazon Web Services), examining XML structures, transforming the data, and loading that data into an updatable database. The resulting database is then used to demonstrate the artifact's effectiveness through a variety of inquiries. The process extends researchers' capabilities to use newly available data to investigate accounting, governance, and other questions that were not previously feasible to consider. Data Availability: Data are available from the public sources cited in the text. JEL Classifications: M41; M48; M49.

Background As a nucleolar protein associated with ribosome biogenesis, pescadillo homolog 1 (PES1) has been reported to participate in the development of many cancers. However, its role in prostate cancer is not clearly defined. Therefore, the aim of this study is to explore the effects and the specific mechanism of PES1 in prostate cancer. Methods A microarray-based analysis was performed to analyze differentially expressed genes (DEGs) between prostate cancer and normal samples. Next, the interaction between PES1 and microRNA-1271 (miR-1271) was investigated using bioinformatics analysis in combination with dual-luciferase reporter gene assay. The expression of miR-1271 in prostate cancer cells and tissues was determined using RT-qPCR. Its effects on downstream estrogen receptor β (ERβ) signaling pathway were further examined. Moreover, we analyzed whether miR-1271 affects proliferation, apoptosis, migration and invasion of prostate cancer cells by EdU assay, flow cytometry, and Transwell assay. Lastly, a prostate cancer mouse model was conducted to measure their roles in the tumor growth. Results PES1 was identified as a prostate cancer-related DEG and found to be upregulated in prostate cancer. miR-1271, which was poorly expressed in both cells and tissues of prostate cancer, can specifically bind to PES1. Additionally, overexpression of miR-1271 activated the ERβ signaling pathway. Overexpression of miR-1271 or depletion of PES1 inhibited prostate cancer cell proliferation, migration and invasion, promoted apoptosis in vitro and suppressed tumor growth in vivo. Conclusions Taken together, overexpression of miR-1271 downregulates PES1 to activate the ERβ signaling pathway, leading to the delayed prostate cancer development. Our data highlights the potential of miR-1271 as a novel biomarker for the treatment of prostate cancer.

Boron has been explored as p-block catalysts for nitrogen reduction reaction (NRR) by density functional theory. Unlike transition metals, on which the active centers need empty d orbitals to accept the lone-pair electrons of the nitrogen molecule, the sp3 hybrid orbital of the boron atom can form B-to-N π-back bonding. This results in the population of the N–N π* orbital and the concomitant decrease of the N–N bond order. We demonstrate that the catalytic activity of boron is highly correlated with the degree of charge transfer between the boron atom and the substrate. Among the 21 concept-catalysts, single boron atoms supported on graphene and substituted into h-MoS2 are identified as the most promising NRR catalysts, offering excellent energy efficiency and selectivity against hydrogen evolution reaction.

With continued innovation of semiconductor processes, overlay control has become the most critical and challenging part. Advanced technology nodes require even tighter lithography overlay control, and therefore, high-order process corrections for inter-field (HOPC) and for intra-field (iHOPC) are adopted as a common solution to meet on-product overlay (OPO) specifications. High order corrections often require more measurement shots and more targets in field, which makes optical overlay metrology on scribe line targets the workhorse of overlay control due to its high throughput and low cost-of-ownership. This leads to the additional challenge that the measurement location also affects the accuracy of generated overlay corrections. For example, it is well known that there may be a spatially dependent offset between overlay on targets and the device. This is commonly called a non-zero offset (NZO) [1], which is a comparison between device overlay measured with the CD SEM after etching (AEI) and optical overlay measured on targets after litho (ADI). In addition, the position of targets could impact the validity of corrections modeled using these targets. The targets could be unevenly distributed in field, some targets huddle at an area, while not a single target appears at others. Hence, this kind of target layout has risks generating problematic field corrections at areas without enough targets. In this paper, we propose a hybrid method utilizing CDSEM overlay to fill in the position where optical overlay targets are deficient. With iHOPC model terms generated by optical overlay targets only, CDSEM metrology results from real devices reveal significantly larger overlay in areas with no targets. By means of this method, the mis-correction at locations where optical overlay targets are deficient is significantly restored, and consequently the OPO mean+3sigma is suppressed to

Additional file 1: Table S1. Transfection sequence.

Additional file 2. Original images of Western blot.

In this study, we reported that a porous perovskite LaNiO 3 prepared by a precipitation-combustion method exhibited significant catalytic effect on hydrogen storage properties of Mg. It is demonstrated that the optimal H-absorption property was achieved on the composite containing 10 wt.% porous LaNiO 3 with a milling time of 10 h, 5.1 wt.% hydrogen can be absorbed within 1.0 min at 200 °C. The activation energy of hydrogenation of the composite is ca. 7.05 kJ/mol H 2 and the rate-controlling step is controlled by H-diffusion at a temperature higher than 200 °C. SEM, XRD and XPS results indicated that the prominent hydrogen storage properties of MgH 2 catalyzed by the porous LaNiO 3 are resulted from the uniform distribution of porous LaNiO 3 with high BET surface in the matrix of MgH 2 as well as the synergistic catalytic effect of LaH 3 and Mg 2 NiH 4 formed in situ at the hydrogenation process.

In this paper, we synthesized graphene-supported TiO2 nanoparticles (TiO2@rGO) via solvothermal method with different solvents. The combined effect of ethylene glycol (EG) and graphene makes fine, uniform TiO2 nanoparticles during solvothermal process. The effects of milling time and TiO2 content on hydrogen storage performance of MgH2 were investigated systematically. The MgH2-70TiO2@rGO-EG composite milled for 10 h starts to release hydrogen at 240 °C. The composite can desorb 6.0 wt% hydrogen within 6 min at 300 °C, while it can absorb 5.9 wt% hydrogen within 2 min at 200 °C. XPS and TEM results indicate that Mg encapsulated with catalyst as well as Ti4+ partially reduced to Ti2+ can make more intimate contacts and promote the charge transfer, which are responsible for the good de-/hydrogenation kinetics performance of MgH2.

An induction brazing process has been developed to seal BaCo0.7Fe0.2Nb0.1O3-δ (BCFN) membrane tubes to metal supports using Ag-Cu alloy in air. The closed-one-end BCFN membrane tubes with an outer diameter of 16 mm and a length of 560 mm were prepared by slip casting. The thermal expansion behaviors of the BCFNO membrane, Ag braze and 310S stainless steel were characterized. A sleeve joint was optimized to reduce the stresses caused by the mismatching in thermal expansions. Ag-1 mol%Cu braze was chosen as brazing filler duo to its good wettability for both the membranes and the metal substrates and thin and continuous reaction layers. Based on the characteristics of the BCFN membrane, a temperature schedule was exploited to successfully achieve the induction brazing of the BCFN membrane tubes to the 310S supports using Ag-1 mol%Cu in air. The entire time needed is about 80 min. The brazed assemble subjected to 15 thermal cycles still exhibits no degradation in joint hermeticity and stable oxygen permeation flux. The result indicates that induction brazing can efficiently join large membrane tubes with high thermal expansion to their metal supports.

Activation reduction and hydrogen storage capacity enhancement in TiFe-based materials have been challenging problems for the last few decades. In this study, the Cu and Y were introduced in Ti-Fe-Mn alloy and the modified Ti 0.95 Y 0.05 Fe 0.86 Mn 0.05 Cu 0.05 alloy was melted via water-cooled copper crucible to investigate its hydrogenation performances including the storage capacity and kinetics. The phase analysis, morphology and chemical composition were carried out by means of X-rays diffraction (XRD), optical microscope (OM) and scanning electron microscope/energy dispersive spectroscopy (SEM/EDS) respectively. Afterward, the hydrogen storage capacity and kinetics were studied. The XRD results confirmed the CsCl order structure of the as-synthesized alloy and the surface morphology studies revealed that the alloy was biphasic in nature, composed of the TiFe alloy matrix and Cu 2 Y secondary phase. The results showed that the addition of element Y could be enhanced significantly the hydrogen storage capacity due to the enlargement of lattice parameters and the maximum capacity 1.85 wt% at 20 °C was observed. In addition, the activation and kinetic performances of the hydrogenated alloy could be improved significantly due to the Cu and the intermetallic secondary phase Cu 2 Y. The study revealed that the intermetallic secondary phase (Cu 2 Y) provided fresh surfaces which accelerated the propagation of hydrogen flux into the alloy.

Based reactive air brazing technique, interfacial reaction and microstructure formation of Ag-6.6 mol% Cu wetting on BaCo 0.7 Fe 0.2 Nb 0.1 O 3-δ (BCFNO) membrane in air were investigated. The interfacial microstructural analysis revealed that at high temperature Ag-Cu alloy transformed into Ag-Cu-O braze in air and the liquid braze penetrated into BCFNO matrix along the grain boundaries. Cu-O in the liquid braze reacted with BCFNO to form CoCuO 2 and Ba 2 Cu 3 O 5+x confirmed by XRD. Ridge formed quickly at the triple line as a result of the migration of the interfacial reaction products and in response to the vertical component of force from surface tension. The rapid interfacial reaction and ridging at the spreading front actually stalled the spreading of the liquid braze, rather than a continuous layer of smoother, barrier-free reaction phase forming and driving accompanied spreading. Low macroscopic contact angles between the braze and BCFNO substrate were observed due to the evolution of the ridge composed of the interfacial reaction products near the tripe line.

In this study, migration mechanism of sulfur impurity contained in dualphase membrane (DPM) of Ce0.9Gd0.1O2−δ-SrCo0.8Fe0.1Nb0.1O3−δ during oxygen permeation process was systematically investigated. Sulfate phase was observed on the permeate side of the DPM after oxygen permeation using CO2 as sweep gas. Experimental results indicated that the migration of sulfur was driven by the chemical potential gradient of oxygen and CO2 sweeping obviously speeded up the migration rate. Theoretical calculations on the SrCoO3 suggested that Sr atoms tend to shift from subsurface to the surface even the initial surface is fully terminated by Co/O, which is beneficial to the CO2 adsorption and generates Sr- and O-vacancies. Sulfur atoms favor to occupy O-vacancies in the beginning; however, due to the formation of carbonates associated with CO2 sweeping, sulfur may hop from the O-vacancies in the bulk to the Sr-vacancies on the surface, forming mixed sulfate and carbonate. In addition, the decrease of sulfur impurity leads to an increase of oxygen permeation flux, about a high and stable flux of 0.30 mL min−1 cm2 was achieved at 900 °C under air/CO2 gradient.

Bao.8La0.2Co0.88−x Fe x Nb0.12O3−δ membranes (BLCFN) with different Fe-doping were successfully prepared by solid-state reaction method. The microstructure, oxygen permeability, thermal analysis, and oxygen permeation stability using CO2 as sweep gas were systematically investigated. After being calcined under pure CO2, BLCFN membranes remain their major perovskite phase but diffraction peaks of BaCO3, CoO appeared on the membranes which Fe content is less than 0.2. Apparent activation energy of oxygen permeation are around 60–70 kJ/mol for all membranes. With the increase of Fe-doping content, the flux through BLCFN membranes decreases but the degradation of oxygen flux becomes less pronounced when CO2 is used as sweep gas at 850 °C. Enhanced CO2 resistance of the perovskite would be resulted from an increasing average binding energy due to the Fe-doping. For the membrane where the Fe-doped content equals to 0.2, the oxygen permeation flux is 0.96 mL cm−2 min−1 at 900 °C with He sweeping. When using pure CO2 as sweep gas, the oxygen permeation flux decreases slightly in the first 50 h and then reaches a steady state of ~0.31 mL cm−2 min−1 for more than 60 h in a prolonged continuous oxygen operation. The observations indicated that a stable oxygen permeation could be realized by suitable elemental doping in a single perovskite membrane.

The development of transition metal oxide oxygen evolution reaction (OER) electrocatalysts provides a new design strategy for renewable energy technologies (water electrolyzers and metal air cells). In the perovskite metal oxide family, we chose SrCo0.8Fe0.1Nb0.1O3-δ (SCFN) OER catalyst with excellent catalytic properties, and in order to further increase its performance. Here, we treat mesoporous SCFN perovskite electrocatalysts with H2O2. After 5 times treatment in H2O2, the specific surface area of SCFN-5 reaches 20.9 m2 g−1, whereas as-prepared SCFN-0 only has 2.3 m2 g−1. SCFN-5 catalyst shows significantly high OER catalytic activity, displaying an overpotential of 0.44 V at 10 mA cm−2 and charge transfer resistance (Rct) value of 59 Ω, which are much lower than those of untreated and ball-milled SCFN samples. Our results indicate that several factors, including the high surface area, good charge transfer abilities, formation of hydrous oxide and the oxidation of Co3+ may contribute to the excellent OER activity.

The influence of chromium in metal components on oxygen permeation and microstructure of BaCo 0.7 Fe 0.2 Nb 0.1 O 3− δ (BCFNO) membrane was investigated under the condition of the oxygen-permeable membrane reactors. In the presence of chromia-forming metal components, the oxygen permeation flux decreased by about 2.4% and 10% when using dry air and humidified air (4% H 2 O) for 100 h at 850 °C, respectively. In the presence of chromia-forming alloys on the permeate side, the oxygen permeation flux decreased by 7% within 100 h. Due to the deposition of volatile Cr species from chromia-forming alloys and formation of spinel phases of BaCrO 4 and BaCr 2 O 4 on the membrane surfaces, the performance of the membrane reactors deteriorated continuously as a function of time. Poisoning of chromium species is also a critical issue for the application of MIEC oxygen-permeable membrane reactors.

In this study, the degradation and recovery mechanisms of perovskite Ba1.0Co0.7Fe0.2Nb0.1O3−δ (BCFN) membrane under a CO2-containing atmosphere were investigated. The oxygen permeability of the BCFN membrane is degraded quickly with pure CO2 gas in the sweep side and then would be partially recovered if the sweep gas changes to 5% CO2. It is found that the existence of oxygen can stabilize the cubic perovskite structure of BCFN. Isotopic exchange test confirms the fast exchange of oxygen between the lattice oxygen of BCFN bulk and the oxygen in the formed carbonate. Pores or cracks are generated during the dynamical exchange of oxygen and serve as the permeable channels of oxygen, resulting in the partial recovery of oxygen permeability under 5% CO2 concentration.

Ce 0.9 Gd 0.1 O 2−δ –SrCo 0.8 Fe 0.1 Nb 0.1 O 3−δ dual-phase membranes (CGO-SCFN DPM) with different weight ratios were successfully prepared by solid-state reaction method. The microstructure, oxygen permeability, rate-determining step, and oxygen permeation stability using CO 2 as sweep gas were systematically investigated. It was found that the oxygen flux through DPM decreases with the increase of CGO content. For membranes of 80CGO-20SCFN with the thicknesses of 1.0 mm and 0.6 mm, the bulk-diffusion resistance and the interfacial exchange resistances of each side were determined according to a permeation mode. A stable oxygen flux of 0.80 mL min −1 ·cm 2 at 900 °C for the 0.6 mm thick membrane with a porous coating on the permeate side was achieved in comparison of 0.48 mL min −1 ·cm 2 for the 1.0 mm membrane without coating. The 80CGO-20SCFN DPM also shows a good tolerance to pure CO 2 , the oxygen flux could reach 0.50 mL min −1 ·cm 2 at 900 °C.

BaCo1−xNbxO3−δ (BCNx, x = 0.1–0.2) membranes were synthesized through conventional solid-phase reactions. The introduction of niobium facilitates the formation of the cubic perovskite structure and decreases oxygen nonstoichiometry. BCNx membranes possess higher oxygen permeation flux compared with BaCo0.7Fe0.2Nb0.1O3−δ membrane at the same condition. A stable permeation flux as high as 2.61 ml cm−2 min−1 is obtained through BaCo0.9Nb0.1O3−δ membrane at 900 °C under the Air/He gradient. Long-time permeation study shows that the oxygen fluxes of BCNx membranes are stable at 900 °C but degrade slowly with time at 850 °C. XRD and TG–DSC results indicate that the degradation behavior occured at 850 °C is due to the phase transition from the cubic perovskite to monoclinic or orthorhombic structure, which is governed by the oxygen partial pressure and temperature. The oxidation of cobalt ion is considered to be the nature for the phase transition, which makes the tolerance factor increasing and results in structural destabilization.

The qualified green BaCo 0.7 Fe 0.2 Nb 0.1 O 3− δ (BCFNO) tubular membranes with length of 700 mm were successfully prepared using the most cost effective slip casting techniques. The optimum slurry composition was identified and some primary factors affecting microstructures, relative density and mechanical strength of membrane tubes were studied in details. Vertical sintering was developed to sinter the long membrane tubes. Dense and defect-free BCFNO membrane tubes with a length of around 560 mm were successfully achieved after the optimized controlled sintering process. A high oxygen permeation flux of 12 cm 3 cm −2 min −1 was achieved under the gradient of COG/air at 875 °C over 90 h. This simple and cost-effective fabrication technique can be used for mass production.

The permeability and stability of Sm0.7Sr0.3CoO3−δ (SSCO) regarding the special requirements for carbon capture and storage (CCS) application were investigated. Pure CO2 was used as the sweep gas at 900 °C, leading to that the oxygen permeation flux decreases by about 34 %. Several cycles of changing the sweep gas between helium and CO2 indicate the good reversibility of this degradation. Both carbonate formation and adsorption of CO2 on the membrane surface are responsible for the degradation of the membrane performance. The better CO2 resistance results from the substitution of Sm for Sr due to the higher acidity of Sm2O3 (1.278) than that of SrO (0.978) and a discontinuous layer of carbonate.

Ba1.0Co0.7Fe0.2Nb0.1O3–δ (BCFN) oxide with perovskite cubic structure was synthesized by solid state reaction method. CO2 corrosion of BCFN membrane was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance infrared Fourier-transformed spectroscopy (DRIFT) and X-ray absorption fine structure spectroscopy (XAFS). Cobalt (Co) K-edge absorption spectra of BCFN annealed in CO2 reveal that the oxidation states of Co in all the samples were larger than +3 and they decreased with the increase of calcination time. At 800 °C, 1% CO2 introduced into He could speed up the reduction of Co cations in comparison with pure He. In addition, sulfate ions in the bulk of BCFN membrane preferred to migrate to the surface under CO2 calcination and form monoclinic Ba(CO3)0.9(SO4)0.1 besides orthorhombic witherite. Moreover, SEM results indicate that the nucleation and growth of carbonates grains started at the grain boundary of the membrane.

A stepwise phase transition in the formation of lithium amidoborane via the solid-state reaction of lithium hydride and ammonia borane has been identified and investigated. Structural analyses reveal that a lithium amidoborane-ammonia borane complex (LiNH(2)BH(3).NH(3)BH(3)) and two allotropes of lithium amidoborane (denoted as alpha- and beta-LiNH(2)BH(3), both of which adopt orthorhombic symmetry) were formed in the process of synthesis. LiNH(2)BH(3).NH(3)BH(3) is the intermediate of the synthesis and adopts a monoclinic structure that features layered LiNH(2)BH(3) and NH(3)BH(3) molecules and contains both ionic and dihydrogen bonds. Unlike alpha-LiNH(2)BH(3), the units of the beta phase have two distinct Li(+) and [NH(2)BH(3)](-) environments. beta-LiNH(2)BH(3) can only be observed in energetic ball milling and transforms to alpha-LiNH(2)BH(3) upon extended milling. Both allotropes of LiNH(2)BH(3) exhibit similar thermal decomposition behavior, with 10.8 wt % H(2) released when heated to 180 degrees C; in contrast, LiNH(2)BH(3).NH(3)BH(3) releases approximately 14.3 wt % H(2) under the same conditions.

Slip casting is a significant method and it is widely used in ceramic manufacturing. In order to investigate the influence of water processing in slurry fabrication on microstructure and oxygen permeation of Ba1.0Co0.7Fe0.2Nb0.1O3−δ (BCFN) membrane, disk-shaped membranes are made from powders with/without water processing and these membranes are checked by XRD, SEM and oxygen permeation measurement. We find barium of material dissolves into water during slurry fabrication through ICP-OES method and the A-site stoichiometric ratio is 0.986 because of the water processing, and the oxygen permeation flux of water-treated membrane is 25.2% lower than that of original membrane after sintered at 1110 °C. With the increase of sintering temperature, the oxygen permeation of water-treated membrane almost recovers and is only 7% lower than the original membrane while sintered at 1150 °C. A composition segregation and homogenization mechanism is proposed through microstructure and properties analysis.

CAS [KGCX2-YW-806, KJCX2-YW-H21, 2009AA05Z108, 2010CB631304]; US Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-06CH11357]

In this work, dehydrogenation and rehydrogenation of three LiNH2/CaH2 samples with LiNH2/CaH2 molar ratio of 2/1, 3/1 and 4/1 were systematically investigated. Remarkable differences were observed in the temperature dependence of hydrogen desorption and subsequent absorption. LiNH2/CaH2 in a molar ratio of 2/1 transforms to ternary imide Li2Ca(NH)2 after desorbing about 4.5 wt.% H2 at 350 °C. And it has a reversible hydrogen storage capacity of 2.7 wt.% at 200 °C. As for the LiNH2/CaH2 mixture in a molar ratio of 4/1, it transforms to a new compound with a composition of Li4CaN4H6 after being dehydrogenated at 350 °C. The rehydrogenation of both LiCa(NH)2 and Li4CaN4H6 gives LiNH2, LiH and the solid solution of 2CaNH–Ca(NH2)2.

In this paper, we reported that the prepared nickel coated carbon nanofibers (NiCNFs) by electroless plating method exhibited superior catalytic effect on hydrogen absorption/desorption of magnesium (Mg). It is demonstrated that the nanocomposites of MgH2/5 wt.% NiCNFs prepared by ball milling could absorb hydrogen very fast at low temperatures, e.g. absorb similar to 6.0 wt.% hydrogen in 5 min at 473 K and similar to 5.0 wt.% hydrogen in 10 min even at a temperature as low as 423 K. More importantly, the desorption of hydrogen was also significantly improved with additives of NiCNFs. Diffraction scanning calorimetry (DSC) measurement indicated that the peak desorption temperature decreased 50 K and the onset temperature for desorption decreased 123 K. The composites also desorbed hydrogen fast, e.g. desorb 5.5 wt.% hydrogen within 20 min at 573 K. It is suggested that the new phase of Mg2Ni, and the nano-sized dispersed distribution of Ni and carbon contributed to this significant improvement. Johnson-Mehl-Avrami (JMA) analysis illustrated that hydrogen diffusion is the rate-limiting step for hydrogen absorption/desorption. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

A “co-precipitation” method was applied to introduce nanosized Co- and Ni-based catalysts to ammonia borane. It was observed that approximately 1 equiv. of hydrogen was evolved from the doped ammonia borane samples at a temperature as low as 59 °C. Moreover, the catalytic dehydrogenation did not present any induction period, undesirable byproduct borazine, or sample forming. Electron paramagnetic resonance (EPR) characterization revealed that Co in a partially reduced state is the active species in the catalytic dehydrogenation of ammonia borane.

BN – NH x samples were synthesized by ball milling hexagonal boron nitride (h-BN) under hydrogen and/or ammonia atmosphere firstly. Then, the BN – NH x samples were ball milled with lithium hydride under hydrogen atmosphere to synthesize Li–BN–H composites. XRD, FT-IR and TG-MS were used to investigate the microstructure and gas desorption properties of samples. Experimental results show that hydrogen and ammonia can be chemically absorbed in h-BN by mechanical milling method. It is found that nanostructure, which formed by ball milling h-BN under hydrogen, is of great advantage to ammonia absorption. For the Li–BN–H composite, hydrogen starts to be released around 100 °C and the peak temperature is around 200 °C, 5.0 wt% hydrogen was desorbed during heating up to 500 °C without ammonia emission.

Synergistic effect of metallic couple and carbon nanotubes on Mg results in an ultrafast kinetics of hydrogenation that overcome a critical barrier of practical use of Mg as hydrogen storage materials. The ultrafast kinetics is attributed to the metal-H atomic interaction at the Mg surface and in the bulk (energy for bonding and releasing) and atomic hydrogen diffusion along the grain boundaries (aggregation of carbon nanotubes) and inside the grains. Hence, a hydrogenation mechanism is presented.

Magnesium and its alloys have shown a great potential in effective hydrogen storage due to their advantages of high volumetric/gravimetric hydrogen storage capacity and low cost. However, the use of these materials in fuel cells for automotive applications at the present time is limited by high hydrogenation temperature and sluggish sorption kinetics. This paper presents the recent results of design and development of magnesium-based nanocomposites demonstrating the catalytic effects of carbon nanotubes and transition metals on hydrogen adsorption in these materials. The results are promising for the application of magnesium materials for hydrogen storage, with significantly reduced absorption temperatures and enhanced ab/desorption kinetics. High level Density Functional Theory calculations support the analysis of the hydrogenation mechanisms by revealing the detailed atomic and molecular interactions that underpin the catalytic roles of incorporated carbon and titanium, providing clear guidance for further design and development of such materials with better hydrogen storage properties.

The microstructure and absorption/desorption characteristics of composite M-H, and 5 wt % as-prepared single-walled carbon nanotubes (MgH2-5ap) obtained by the mechanical grinding method were investigated. Experimental results show that the MgH2-5ap sample exhibits faster absorption kinetics and relatively lower desorption temperature than pure MgH2 or MgH2-purified single-walled carbon nanotube composite. Storage capacities of 6.0 and 4.2 wt % hydrogen for the MgH2-5ap composite were achieved in 60 min at 423 and 373 K, respectively. Furthermore, its desorption temperature was reduced by 70 K due to the introduction of as-prepared single-walled carbon nanotubes (SWNTs). In addition, the different effects of SWNTs and metallic catalysts contained in the as-prepared SWNTs were also investigated and a hydrogenation mechanism was proposed. It is suggested that metallic particles may be mainly responsible for the improvement of the hydrogen absorption kinetics, and SWNTs for the enhancement of hydrogen absorption capacity of MgH2.

LiNH2BH3·NH3BH3, synthesized by reacting LiH and 2 equiv of NH3BH3 or by reacting equiv LiNH2BH3 and NH3BH3, is composed of alternative LiNH2BH3 and NH3BH3 layers. The compound starts to release hydrogen at 57 °C and can desorb ca. 14.0 wt % hydrogen in a stepwise manner with peak temperatures at 80 and 140 °C, respectively.