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One of the ideal energy carriers for the future is hydrogen. It has a high energy density and is a source of clean energy. A crucial step in the development of the hydrogen economy is the safety and affordable storage of a large amount of hydrogen. Thus, owing to its large storage capacity, good reversibility, and low cost, Magnesium hydride (MgH₂) was taken into consideration. Unfortunately, MgH₂ has a high desorption temperature and slow ab/desorption kinetics. Using the ball milling technique, adding cobalt lanthanum oxide (LaCoO₃) to MgH₂ improves its hydrogen storage performance. The results show that adding 10 wt.% LaCoO₃ relatively lowers the starting hydrogen release, compared with pure MgH₂ and milled MgH₂. On the other hand, faster ab/desorption after the introduction of 10 wt.% LaCoO₃ could be observed when compared with milled MgH₂ under the same circumstances. Besides this, the apparent activation energy for MgH₂–10 wt.% LaCoO₃ was greatly reduced when compared with that of milled MgH₂. From the X-ray diffraction analysis, it could be shown that in-situ forms of MgO, CoO, and La₂O_3, produced from the reactions between MgH₂ and LaCoO₃, play a vital role in enhancing the properties of hydrogen storage of MgH₂. Full article

Magnesium hydride (MgH₂) has received outstanding attention as a safe and efficient material to store hydrogen because of its 7.6 wt.% hydrogen content and excellent reversibility. Nevertheless, the application of MgH₂ is obstructed by its unfavorable thermodynamic stability and sluggish sorption kinetic. To overcome these drawbacks, ball milling MgH₂ is vital in reducing the particle size that contribute to the reduction of the decomposition temperature. However, the milling process would become inefficient in reducing particle sizes when equilibrium between cold-welding and fracturing is achieved. Therefore, to further ameliorate the performance of MgH₂, nanosized cobalt titanate (CoTiO₃) has been synthesized using a solid-state method and was introduced to the MgH₂ system. The different weight percentages of CoTiO₃ were doped to the MgH₂ system, and their catalytic function on the performance of MgH₂ was scrutinized in this study. The MgH₂ + 10 wt.% CoTiO₃ composite presents the most outstanding performance, where the initial decomposition temperature of MgH₂ can be downshifted to 275 °C. Moreover, the MgH₂ + 10 wt.% CoTiO₃ absorbed 6.4 wt.% H₂ at low temperature (200 °C) in only 10 min and rapidly releases 2.3 wt.% H₂ in the first 10 min, demonstrating a 23-times-faster desorption rate than as-milled MgH₂ at 300 °C. The desorption activation energy of the 10 wt.% CoTiO₃-doped MgH₂ sample was dramatically lowered by 30.4 kJ/mol compared to undoped MgH₂. The enhanced performance of the MgH₂–CoTiO₃ system is believed to be due to the in situ formation of MgTiO₃, CoMg₂, CoTi₂, and MgO during the heating process, which offer a notable impact on the behavior of MgH₂. Full article

Nano-confined chemical reactions bear great promise for a wide range of important applications in the near-to-medium term, e.g., within the emerging area of chemical storage of renewable energy. To explore this important trend, in the present work, resorcinol-/formaldehyde-based carbon aerogels were prepared by sol-gel polymerisation of resorcinol, with furfural catalysed by a sodium-carbonate solution using ambient-pressure drying. These aerogels were further carbonised in nitrogen to obtain their corresponding carbon aerogels. Through this study, the synthesis parameters were selected in a way to obtain minimum shrinkage during the drying step. The microstructure of the product was observed using Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) imaging techniques. The optimised carbon aerogels were found to have pore sizes of ~21 nm with a specific accessible surface area equal to 854.0 m²/g. Physical activation of the carbon aerogel with CO₂ generates activated carbon aerogels with a surface area of 1756 m²/g and a total porosity volume up to 3.23 cm³/g. The product was then used as a scaffold for magnesium/cobalt-hydride formation. At first, cobalt nanoparticles were formed inside the scaffold, by reducing the confined cobalt oxide, then MgH₂ was synthesised as the second required component in the scaffold, by infiltrating the solution of dibutyl magnesium (MgBu₂) precursor, followed by a hydrogenation reaction. Further hydrogenation at higher temperature leads to the formation of Mg₂CoH₅. In situ synchrotron X-ray diffraction was employed to study the mechanism of hydride formation during the heating process. Full article