Carbon Aerogel Scaffold Research Articles

Porous hybrid scaffold strategy for the realization of lightweight, highly efficient microwave absorbing materials

• Bacterial cellulose (BC) derived carbon aerogel (CA) with a robust nanofibrous network was used as a conductive loss scaffold to dissipate EM waves effectively. • The tunable size and morphologies of ZnO crystals microparticles with excellent dielectric properties and low electrical conductivity were decorated on the CA scaffold to adjust dielectric parameters and impedance matching adequately. • The CA@ZnO composites achieve a superior EM absorbing performance with a broad effective absorbing bandwidth (whole X band) and a minimum reflection coefficient (−53.3 dB). Exploring an advanced and efficient electromagnetic (EM) wave absorbing material by improving dielectric loss capacity and adjusting impendence matching is crucial yet challenging. Herein, the bacterial cellulose (BC) derived carbon aerogel (CA) with a robust nanofibrous network was used as a conductive loss scaffold to dissipate EM waves effectively, and the ZnO microparticles with excellent dielectric properties and low electrical conductivity were decorated on the scaffold to adjust dielectric parameters and impedance matching adequately. By using different zinc precursors, the tunable size and morphologies of ZnO crystals were obtained due to the growth rate of different crystallographic, including flower-like, nanorod like, and cauliflower-like morphologies, which is beneficial to strong multiple reflections, intensive interfacial polarization, better impendence matching, as well as excellent maintenance of the hierarchical structure. Owing to the appropriate impendence matching and the considerable EM wave dissipation, the CA@ZnO composites achieve a superior EM absorbing performance with a broad effective absorbing bandwidth (whole X band) and a minimum reflection coefficient (−53.3 dB). This work paves a new way for developing lightweight and highly efficient EM absorbing materials comprising the carbon scaffold and semiconductor microparticles.

Hydrogen Storage Stability of Nanoconfined MgH2 upon Cycling

It is of utmost importance to optimise and stabilise hydrogen storage capacity during multiple cycles of hydrogen release and uptake to realise a hydrogen-based energy system. Here, the direct solvent-based synthesis of magnesium hydride, MgH2, from dibutyl magnesium, MgBu2, in four different carbon aerogels with different porosities, i.e., pore sizes, 15 < Davg < 26 nm, surface area 800 < SBET < 2100 m2/g, and total pore volume, 1.3 < Vtot < 2.5 cm3/g, is investigated. Three independent infiltrations of MgBu2, each with three individual hydrogenations, are conducted for each scaffold. The volumetric and gravimetric loading of MgH2 is in the range 17 to 20 vol % and 24 to 40 wt %, which is only slightly larger as compared to the first infiltration assigned to the large difference in molar volume of MgH2 and MgBu2. Despite the rigorous infiltration and sample preparation techniques, particular issues are highlighted relating to the presence of unwanted gaseous by-products, Mg/MgH2 containment within the scaffold, and the purity of the carbon aerogel scaffold. The results presented provide a research path for future researchers to improve the nanoconfinement process for hydrogen storage applications.

Reversibility of LiBH4 Facilitated by the LiBH4–Ca(BH4)2 Eutectic

The hydrogen storage properties of eutectic melting 0.68LiBH4–0.32Ca(BH4)2 (LiCa) as bulk and nanoconfined into a high surface area, SBET = 2421 ± 189 m2/g, carbon aerogel scaffold, with an average pore size of 13 nm and pore volume of Vtot = 2.46 ± 0.46 mL/g, is investigated. Hydrogen desorption and absorption data were collected in the temperature range of RT to 500 °C (ΔT/Δt = 5 °C/min) with the temperature then kept constant at 500 °C for 10 h at hydrogen pressures in the range of 1–8 and 134–144 bar, respectively. The difference in the maximum H2 release rate temperature, Tmax, between bulk and nanoconfined LiCa during the second cycle is ΔTmax ≈ 40 °C, which over five cycles becomes smaller, ΔTmax ≈ 10 °C. The high temperature, Tmax ≈ 455 °C, explains the need for high temperatures for rehydrogenation in order to obtain sufficiently fast reaction kinetics. This work also reveals that nanoconfinement has little effect on the later cycles and that nanoconfinement of pure LiBH4 has a strong effect in o...

Hydrogen Desorption Properties of Bulk and Nanoconfined LiBH4-NaAlH4

Nanoconfinement of 2LiBH4-NaAlH4 into a mesoporous carbon aerogel scaffold with a pore size, BET surface area and total pore volume of Dmax = 30 nm, SBET = 689 m2/g and Vtot = 1.21 mL/g, respectively is investigated. Nanoconfinement of 2LiBH4-NaAlH4 facilitates a reduction in the temperature of the hydrogen release by 132 °C, compared to that of bulk 2LiBH4-NaAlH4 and the onset of hydrogen release is below 100 °C. The reversible hydrogen storage capacity is also significantly improved for the nanoconfined sample, maintaining 83% of the initial hydrogen content after three cycles compared to 47% for that of the bulk sample. During nanoconfinement, LiBH4 and NaAlH4 reacts to form LiAlH4 and NaBH4 and the final dehydrogenation products, obtained at 481 °C are LiH, LiAl, AlB2 and Al. After rehydrogenation of the nanoconfined sample at T = 400 °C and p(H2) = 126 bar, amorphous NaBH4 is recovered along with unreacted LiH, AlB2 and Al and suggests that NaBH4 is the main compound that can reversibly release and uptake hydrogen.

2LiBH4–MgH2 nanoconfined into carbon aerogel scaffold impregnated with ZrCl4 for reversible hydrogen storage

Nanoconfinement of 2LiBH4–MgH2 composite into carbon aerogel scaffold (CAS) impregnated with zirconium (IV) chloride (ZrCl4) for reversible hydrogen storage is proposed. Nanoconfined samples prepared with hydride:ZrCl4-doped CAS weight ratios of 1:1, 1:2, and 1:3 are prepared by melt infiltration technique. Successful nanoconfinement of all samples is confirmed and it is found that the sample with high content of hydride with respect to ZrCl4-doped CAS (1:1 weight ratio) shows partial pore blocking. The most suitable hydride:ZrCl4-doped CAS weight ratio providing the best performance based on dehydrogenation temperature and kinetics as well as hydrogen storage capacity is 1:2. Reduction of dehydrogenation temperature and faster kinetics are obtained after doping with ZrCl4. Up to 97 and 93% of theoretical hydrogen storage capacity are released and reproduced after four cycles of nanoconfined sample with ZrCl4 (1:2 weight ratio). Deficient hydrogen content with respect to theoretical capacity can be due to partial dehydrogenation during melt infiltration and formation of thermally stable [B12H12]2- phases during cycling.

Ternary LiBH4–MgH2–NaAlH4 hydride confined into nanoporous carbon host for reversible hydrogen storage

Ternary hydride of LiBH4–MgH2–NaAlH4 confined into carbo n aerogel scaffold (CAS) via melt infiltration for reversible hydrogen storage is proposed. Nanoconfinement of hydrides into CAS is obtained together with surface occupation of some phases, such as Al and/or LiH. Regarding nanoconfinement, not only multiple-step decomposition of LiBH4–MgH2–NaAlH4 hydride reduces to about single step, but also reduction of dehydrogenation temperature is significantly observed, for example, ∆T up to 70°C regarding last dehydrogenation step. Moreover, decomposition of NaBH4 in nanoconfined sample can be done at 360°C (dehydrogenation temperature in this study), which is 115 and 180°C lower than that of NaBH4 in milled LiBH4–MgH2–NaAlH4 and bulk NaBH4, respectively. The reaction of LiBH4+NaAlH4→LiAlH4+NaBH4 takes place during nanoconfinement and the decomposition of LiAlH4 is observed, resulting deficient hydrogen content liberated. However, hydrogen content released (1st cycle) and reproduced (2nd–4th cycles) from this ternary hydride enhances up to 11% and 22% of full hydrogen storage capacity due to nanoconfinement. After rehydrogenation (T=360°C and P(H2)=50bar H2 for 12h), NaBH4, MgH2, and Li3AlH6 are reversible, whereas Li3AlH6 and NaBH4 in milled sample cannot be recovered due to deficient hydrogen pressure (T=360°C and P(H2)=80bar) and probably evaporation of molten sodium during dehydrogenation, respectively. The latter results in inferior hydrogen content reproduced from milled sample to nanoconfined sample.

Hydrogen storage properties of nanoconfined LiBH4–NaBH4

In this study a eutectic melting composite of 0.62LiBH4–0.38NaBH4 has been infiltrated in two nanoporous resorcinol formaldehyde carbon aerogel scaffolds with similar pore sizes (37 and 38 nm) but different BET surface areas (690 and 2358 m2/g) and pore volumes (1.03 and 2.64 mL/g). This investigation clearly shows decreased temperature of hydrogen desorption, and improved cycling stability during hydrogen release and uptake of bulk 0.62LiBH4–0.38NaBH4 when nanoconfined into carbon nanopores. The hydrogen desorption temperature of bulk 0.62LiBH4–0.38NaBH4 is reduced by ∼107 °C with the presence of carbon, although a minor kinetic variation is observed between the two carbon scaffolds. This corresponds to apparent activation energies, EA, of 139 kJ mol−1 (bulk) and 116–118 kJ mol−1 (with carbon aerogel). Bulk 0.62LiBH4–0.38NaBH4 has poor reversibility during continuous hydrogen release and uptake cycling, maintaining 22% H2 capacity after four hydrogen desorptions (1.6 wt.% H2). In contrast, nanoconfinement into the high surface area carbon aerogel scaffold significantly stabilizes the hydrogen storage capacity, maintaining ∼70% of the initial capacity after four cycles (4.3 wt.% H2).

Dehydrogenation kinetics, reversibility, and reaction mechanisms of reversible hydrogen storage material based on nanoconfined MgH2−NaAlH4

Studies of dehydrogenation kinetics, reversibility, and reaction mechanisms during de/rehydrogenation of nanoconfined MgH2−NaAlH4 into carbon aerogel scaffold (CAS) for reversible hydrogen storage material are for the first time proposed. Two different MgH2:NaAlH4 molar ratios (1:1 and 2:1) of hydride composite are melt infiltrated into CAS under 1:1 (CAS:hydride composite) weight ratio. Successful nanoconfinement is confirmed by N2 adsorption−desorption. Multiple-step dehydrogenation of milled samples is reduced to two-step reaction due to nanoconfinement. Peak temperatures corresponding to main dehydrogenation of nanoconfined samples significantly reduce as compared with those of milled samples, i.e., ∆T=up to 50 and 34°C for nanoconfined sample with 1:1 and 2:1 (MgH2:NaAlH4) molar ratios, respectively. Hydrogen content released (the 1st cycle) and reproduced (the 2nd, 3rd, and 4th cycles) of nanoconfined samples enhance up to 80% and 68% with respect to theoretical hydrogen storage capacity, respectively, while those of milled samples are 71% and 38%, respectively. Remarkable hydrogen content reproduced after nanoconfinement is due to the fact that metallic Al obtained after dehydrogenation (T=300°C under vacuum) of nanoconfined samples prefer to react with MgH2 and produces Al12Mg17, favorable for reversibility of MgH2−NaAlH4 system, whereas that of milled samples stays in the form of unreacted Al under the same temperature and pressure condition.

Hydrogen sorption and reaction mechanisms of nanoconfined 2LiBH4–NaAlH4

Nanoconfinement of 2LiBH4–NaAlH4 in carbon aerogel scaffold (CAS) via direct melt infiltration is proposed for reversible hydrogen storage. Weight ratios of CAS:2LiBH4–NaAlH4 (2:1, 2:1.5, and 1:1) and melt infiltration temperatures at 185 and 310°C are varied to obtain the most suitable condition for nanoconfinement. It is found that the sample melt infiltrated at 310°C under CAS:2LiBH4–NaAlH4 weight ratio of 2:1, denoted as s1@310 offers the best results based on effective nanoconfinement, high hydrogen content released, and fast dehydrogenation kinetics. Further studies on reversibility shows that up to 89% and 74% H2 with respect to theoretical storage capacity release from s1@310 during the 1st and 2nd dehydrogenations (T=400°C under vacuum), respectively, while those of milled 2LiBH4–NaAlH4 are only 57% and 32%, respectively. The reaction between LiBH4 and NaAlH4 during nanoconfinement produces LiAlH4 and NaBH4. During dehydrogenation, an intermediate phase (LiNa2AlH6) is formed and it decomposes in the temperature range of 203–350°C. Moreover, significant reduction in decomposition temperature of NaBH4 of s1@310 with respect to those of milled 2LiBH4–NaAlH4 and pristine NaBH4 (ΔT=137 and 197°C, respectively) is accomplished. Reversibility of NaBH4, LiAlH4, and LiBH4 are achieved together with unreacted LiH and metallic Al (T=400°C, p(H2)=80bar for 12h). Although irreversibility of metallic Al leads to deficient content of hydrogen desorbed in the 2nd cycle, greater amount of hydrogen reproduced of s1@310 with respect to milled sample is obtained. This is due to the recovery of NaBH4 after rehydrogenation of s1@310, whereas that of milled 2LiBH4–NaAlH4 was not possible due to the evaporation of metallic Na during dehydrogenation.

Effective nanoconfinement of 2LiBH4–MgH2 via simply MgH2 premilling for reversible hydrogen storages

To improve nanoconfinement of LiBH4 and MgH2 in carbon aerogel scaffold (CAS), particle size reduction of MgH2 by premilling technique before melt infiltration is proposed. MgH2 is premilled for 5 h prior to milling with LiBH4 and nanoconfinement in CAS to obtained nanoconfined 2LiBH4–premilled MgH2. Significant confinement of both LiBH4 and MgH2 in CAS, confirmed by SEM–EDS–mapping results, is achieved due to MgH2 premilling. Due to effective nanoconfinement, enhancement of CAS:hydride composite weight ratio to 1:1, resulting in increase of hydrogen storage capacity, is possible. Nanoconfined 2LiBH4–premilled MgH2 reveals a single–step dehydrogenation at 345 °C with no B2H6 release, while dehydrogenation of nanoconfined sample without MgH2 premilling performs in multiple steps at elevated temperatures (up to 430 °C) together with considerable amount of B2H6 release. Activation energy (EA) for the main dehydrogenation of nanoconfined 2LiBH4–premilled MgH2 is considerably lower than those of LiBH4 and MgH2 of bulk 2LiBH4–MgH2 (ΔEA = 31.9 and 55.8 kJ/mol with respect to LiBH4 and MgH2, respectively). Approximately twice faster dehydrogenation rate are accomplished after MgH2 premilling. Three hydrogen release (T = 320 °C, P(H2) = 3–4 bar) and uptake (T = 320–325 °C, P(H2) = 84 bar) cycles of nanoconfined 2LiBH4–premilled MgH2 reveal up to 4.96 wt. % H2 (10 wt. % H2 with respect to hydride composite content), while the 1st desorption of nanoconfined sample without MgH2 premilling gives 4.30 wt. % of combined B2H6 and H2 gases. It should be remarked that not only kinetic improvement and B2H6 suppression are obtained by MgH2 premilling, but also the lowest dehydrogenation temperature (T = 320 °C) among other modified 2LiBH4–MgH2 systems is acquired.

2LiBH4–MgH2–0.13TiCl4 confined in nanoporous structure of carbon aerogel scaffold for reversible hydrogen storage

The investigations based on kinetic improvement and reaction mechanisms during melt infiltration, dehydrogenation, and rehydrogenation of nanoconfined 2LiBH4–MgH2–0.13TiCl4 in carbon aerogel scaffold (CAS) are proposed. It is found that TiCl4 and LiBH4 are successfully nanoconfined in CAS, while MgH2 proceeds partially. In the same temperature (25–500°C) and time (0–5h at constant temperature) ranges nanoconfined 2LiBH4–MgH2–0.13TiCl4 dehydrogenates completely 99% of theoretical H2 storage capacity, while that of nanoconfined 2LiBH4–MgH2 is only 94%. Nanoconfined 2LiBH4–MgH2–0.13TiCl4 performs three-step dehydrogenation at 140, 240, and 380°C. Onset (the first-step) dehydrogenation temperature (140°C), significantly lower than those of nanoconfined sample of 2LiBH4–MgH2 and 2LiBH4–MgH2–TiCl3 (ΔT=140 and 110°C, respectively) is in agreement with the decomposition of eutectic LiBH4–Mg(BH4)2 and lithium–titanium borohydride. For the second and third steps (240 and 380°C), decompositions of LiBH4 destabilized by LiCl solvation and MgH2 are accomplished, respectively. In conclusion, dehydrogenation products are B, Mg, LiH, and TiH. Reversibility of nanoconfined 2LiBH4–MgH2–0.13TiCl4 sample is confirmed by the recovery of LiBH4 after rehydrogenation together with the formation of [B12H12]− derivatives. The superior kinetics during the 2nd, 3rd, and 4th cycles of nanoconfined 2LiBH4–MgH2–0.13TiCl4 to the nanoconfined 2LiBH4–MgH2 can be due to the formations of Ti–MgH2 alloys (Mg0.25Ti0.75H2 and Mg6TiH2) during the 1st rehydrogenation.

Stable cycling and excess capacity of a nanostructured Sn electrode based on Sn(CH3COO)2 confined within a nanoporous carbon scaffold

A high capacity, electrochemically stable, nanostructured Sn electrode for Li ion battery anodes is described. This electrode utilizes a rigid, electrically conductive, nanoporous carbon aerogel scaffold by incorporating tin acetate, Sn(CH3COO)2, into the scaffold pore volume through melt infusion. Incorporation of the Sn(CH3COO)2 by melt infusion ensures a chemically stable contact with the scaffold. The mechanical rigidity of the pore volume confines the Sn to nanometer dimensions without sintering, leading to stable cycling. Separation of the synthesis of the scaffold from the loading with Sn(CH3COO)2 permits optimized division of the scaffold pore volume for expansion and electrolyte access during reaction with Li. Using this design, an electrode based on an aerogel with a 5 nm mode pore size was cycled over 300 times without degradation. In addition, after subtracting the contribution from the carbon scaffold, the capacity exceeded the theoretical capacity for Sn, due to an oxidation reaction occurring at 1.2 V. This excess capacity may be related to the solid–solid or solid–electrolyte interfaces in the electrode, possibly representing a new reversible Li ion reaction.

Nanoconfined 2LiBH4–MgH2–TiCl3 in carbon aerogel scaffold for reversible hydrogen storage

Nanoconfinement of 2LiBH4–MgH2–TiCl3 in resorcinol–formaldehyde carbon aerogel scaffold (RF–CAS) for reversible hydrogen storage applications is proposed. RF–CAS is encapsulated with approximately 1.6 wt. % TiCl3 by solution impregnation technique, and it is further nanoconfined with bulk 2LiBH4–MgH2 via melt infiltration. Faster dehydrogenation kinetics is obtained after TiCl3 impregnation, for example, nanoconfined 2LiBH4–MgH2–TiCl3 requires ∼1 and 4.5 h, respectively, to release 95% of the total hydrogen content during the 1st and 2nd cycles, while nanoconfined 2LiBH4–MgH2 (∼2.5 and 7 h, respectively) and bulk material (∼23 and 22 h, respectively) take considerably longer. Moreover, 95–98.6% of the theoretical H2 storage capacity (3.6–3.75 wt. % H2) is reproduced after four hydrogen release and uptake cycles of the nanoconfined 2LiBH4–MgH2–TiCl3. The reversibility of this hydrogen storage material is confirmed by the formation of LiBH4 and MgH2 after rehydrogenation using FTIR and SR-PXD techniques, respectively.

2LiBH4–MgH2 in a Resorcinol–Furfural Carbon Aerogel Scaffold for Reversible Hydrogen Storage

The reactive hydride composite of 2LiBH4–MgH2 has been melt infiltrated in a resorcinol–furfural (RFF) carbon aerogel scaffold. Dried aerogel of RFF, further pyrolyzed to obtain a carbon aerogel sc...

Nanoconfined 2LiBH4–MgH2 Prepared by Direct Melt Infiltration into Nanoporous Materials

Nanoconfined 2LiBH(4)-MgH2 is prepared by direct melt infiltration of bulk 2LiBH(4)-MgH2 into an inert nanoporous resorcinol-formaldehyde carbon aerogel scaffold material. Scanning electron microscopy (SEM) micrographs and energy dispersive X-ray spectroscopy (EDS) mapping reveal homogeneous dispersion of Mg (from MgH2) and B (from LiBH4) inside the carbon aerogel scaffold. Moreover, nanoconfinement of LiBH4 in the carbon aerogel scaffold is confirmed by differential scanning calorimetry (DSC). The hydrogen desorption kinetics of the nanoconfined 2LiBH(4)-MgH2 is significantly improved as compared to bulk 2LiBH(4)-MgH2. For instance, the nanoconfined 2LiBH(4)-MgH2 releases 90% of the total hydrogen storage capacity within 90 mm, whereas the bulk material releases only 34% (at T = 425 degrees C and p(H-2) = 3.4 bar). A reversible gravimetric hydrogen storage capacity of 10.8 wt % H-2, calculated with respect to the metal hydride content, is preserved over four hydrogen release and uptake cycles. (Less)

Magnesium Hydride Formation within Carbon Aerogel

Magnesium hydride nanoparticles were synthesized within a carbon aerogel (CA) scaffold using a dibutylmagnesium precursor. The synthesis reaction was tracked using small-angle X-ray scattering (SAXS) to analyze the structural evolution during MgH2 formation. The CA/MgH2 composite was also investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM) to provide a better representation of the physical system. The CA has a large quantity of 2 nm pores as shown by nitrogen adsorption data. Both SAXS and TEM investigations confirm that MgH2 does form within the 2 nm pores but XRD proves that there is also a significant quantity of larger MgH2 particles within the system. Variations between hydrogen desorption isotherms from the CA/MgH2 composite and bulk MgH2 are detected that are indicative of changes in the decomposition properties of the small fraction of 2 nm MgH2 nanoparticles within the CA/MgH2 composite, changes which match theoretical predictions.

A Reversible Nanoconfined Chemical Reaction

Hydrogen is recognized as a potential, extremely interesting energy carrier system, which can facilitate efficient utilization of unevenly distributed renewable energy. A major challenge in a future "hydrogen economy" is the development of a safe, compact, robust, and efficient means of hydrogen storage, in particular, for mobile applications. Here we report on a new concept for hydrogen storage using nanoconfined reversible chemical reactions. LiBH4 and MgH2 nanoparticles are embedded in a nanoporous carbon aerogel scaffold with pore size Dmax approximately 21 nm and react during release of hydrogen and form MgB2. The hydrogen desorption kinetics is significantly improved compared to bulk conditions, and the nanoconfined system has a high degree of reversibility and stability and possibly also improved thermodynamic properties. This new scheme of nanoconfined chemistry may have a wide range of interesting applications in the future, for example, within the merging area of chemical storage of renewable energy.

Confinement of MgH2Nanoclusters within Nanoporous Aerogel Scaffold Materials

Nanoparticles of magnesium hydride were embedded in nanoporous carbon aerogel scaffold materials in order to explore the kinetic properties of hydrogen uptake and release. A new modified procedure for the synthesis of magnesium hydride nanoparticles is presented. The procedure makes use of monoliths (approximately 0.4 cm(3)) of two distinct types of nanoporous resorcinol-formaldehyde carbon aerogels loaded with dibutylmagnesium, MgBu(2). Excess MgBu(2) was removed mechanically, and the increase in mass was used as a measure of the amount of embedded MgH(2). Energy-dispersive spectrometry revealed that MgH(2) was uniformly distributed within the aerogel material. In situ synchrotron radiation powder X-ray diffraction showed that MgBu(2) transformed directly to MgH(2) at T approximately 137 degrees C and p(H(2)) = 50 bar. Two distinct aerogel samples, denoted X1 and X2, with pore volumes of 1.27 and 0.65 mL/g and average pore sizes of 22 and 7 nm, respectively, were selected. In these samples, the uptake of magnesium hydride was found to be proportional to the pore volume, and aerogels X1 and X2 incorporated 18.2 and 10.0 wt % of MgH(2), respectively. For the two samples, the volumetric MgH(2) uptake was similar, approximately 12 vol %. The hydrogen storage properties of nanoconfined MgH(2) were studied by Sieverts' measurements and thermal desorption spectroscopy, which clearly demonstrated that the dehydrogenation kinetics of the confined hydride depends on the pore size distribution of the scaffold material; that is, smaller pores mediated faster desorption rates possibly due to a size reduction of the confined magnesium hydride.

The synthesis and hydrogen storage properties of aMgH2 incorporated carbon aerogel scaffold

A new approach to the incorporation ofMgH2 in the nanometer-sized pores of a carbon aerogel scaffold was developed,by infiltrating the aerogel with a solution of dibutylmagnesium (MgBu2) precursor, and then hydrogenating the incorporatedMgBu2 toMgH2. The resulting impregnated material showed broad x-ray diffraction peaks ofMgH2. Theincorporated MgH2 was not visible using a transmission electron microscope, which indicated that the incorporatedhydride was nanosized and confined in the nanoporous structure of the aerogel. The loading ofMgH2 was determined as 15–17 wt%, of which 75% is reversible over ten cycles. IncorporatedMgH2 had>5 times faster dehydrogenation kinetics than ball-milled activatedMgH2, which may be attributed to the particle size of the former beingsmaller than that of the latter. Cycling tests of the incorporatedMgH2 showed that the dehydrogenation kinetics are unchanged over four cycles. Our resultsdemonstrate that confinement of metal hydride materials in a nanoporous scaffold is anefficient way to avoid aggregation and improve cycling kinetics for hydrogen storagematerials.