Catalytic Effects of Decorating AlV₃ Nanocatalyst on Hydrogen Storage Performance of Mg@Mg₁₇Al₁₂ Nanocomposite: Experimental and Theoretical Study

Abstract

Constructing uniformly coated Mg nanoparticles (NPs) with the addition of the Al−V alloy nanocatalyst and retaining the stability of the core@shell structure are challenging issues. In this work, a novel Mg@Mg 17 Al 12 nanocomposite of 120 nm decorated with Al 3 V (5 nm) NPs is prepared by the hydrogen plasma metal reaction method. After the first hydrogenation process at 673 K, the Mg 17 Al 12 shell of 3 nm disproportionates into an Al shell and MgH 2 core, while Al 3 V changes into AlV 3 and Al. After the hydrogenation/dehydrogenation cycle, the Mg 17 Al 12 shell is obtained again, whereas AlV 3 remains unchanged. The nanocomposite can quickly uptake 5.0 wt % H 2 within 30 min at 473 K, and the hydrogen absorption capacities of the nanocomposite are almost stable at 6.3 wt % above 473 K. It can release 4.0 wt % H 2 within 10 min at 573 K. The apparent activation energies for hydrogen absorption and desorption are decreased to 43.3 and 44.7 kJ/ mol H 2 . The AlV 3 nanocatalyst can store hydrogen of 1.0 wt % at 473 K, and the first-principles calculation also implies that the hydrogen dissociation energy on the AlV 3 surface is 0.76 eV, much lower than Mg (0.92 eV). Both experimental and calculation results prove AlV 3 to be a novel and effective nanocatalyst.

Combinations of V2C and Ti3C2 MXenes for Boosting the Hydrogen Storage Performances of MgH2

“…However, its thermal stability is high, and the kinetics is really slow, which severely restricts the practical applications. Many strategies were developed to tailor the performances of MgH 2 , such as nanoscaling, − alloying, − mixing with additives (metals, ,− oxides, ,, halides, and others − ), etc.…”

Hierarchical Structure Carbon-Coated CoNi Nanocatalysts Derived from Flower-Like Bimetal MOFs: Enhancing the Hydrogen Storage Performance of MgH2 under Mild Conditions

“…As an environmentally friendly and sustainable clean energy, hydrogen energy is considered an ideal substitute for traditional energy to solve the increasingly serious energy crisis and slow down climate deterioration. , For the hydrogen economy, hydrogen storage technology still restricts the development of hydrogen energy applications. Compared with gaseous hydrogen storage and liquid hydrogen storage, solid-state hydrogen storage materials have the advantages of high energy density and good safety, which effectively solve the storage problem in the application of hydrogen energy. , In addition, the renewability of solid hydrogen storage materials also effectively avoids environmental pollution. − Among many solid-state hydrogen storage materials, magnesium hydride, which is low-cost and environmentally friendly and has abundant reserves, has attracted much attention from researchers. , MgH 2 is considered to be one of the most potential hydrogen storage materials due to its high theoretical hydrogen storage capacity (7.6 wt %) and excellent reversible properties. − However, due to its high thermodynamic stability and poor kinetic performance, its hydrogen absorption and desorption process requires a high working temperature (>573 K), which limits its practical application. , …”

“…Compared with gaseous hydrogen storage and liquid hydrogen storage, solid-state hydrogen storage materials have the advantages of high energy density and good safety, which effectively solve the storage problem in the application of hydrogen energy. 3,4 In addition, the renewability of solid hydrogen storage materials also effectively avoids environmental pollution. 5−7 Among many solid-state hydrogen storage materials, magnesium hydride, which is low-cost and environmentally friendly and has abundant reserves, has attracted much attention from researchers.…”

Phase Transformation and Performance of Mg-Based Hydrogen Storage Material by Adding ZnO Nanoparticles

“…Compared with traditional high-pressure gas hydrogen storage and low-temperature liquid hydrogen storage, solid hydrogen storage materials have been widely studied because of their advantages of high safety, small occupation area, low energy consumption, and high hydrogen storage density. For example, rare earth hydrogen storage materials [3][4][5], titanium hydrogen storage materials [6][7][8], vanadium hydrogen storage materials [9,10], magnesium hydrogen storage materials [11][12][13][14][15], etc. MgH 2 is considered one of the best hydrogen storage materials owing to its abundant reserves, high calorific value (1.43×10 8 J/kg), high theoretical hydrogen capacity (7.6 wt% H 2 ), no pollution, and excellent reversibility.…”