Investigation of hydrogen storage on Sc/Ti-decorated novel B24N24

Inspired by the TM−N₄ coordination environment in single-atom catalysts, four novel TM-decorated B₂₄N₂₄ (TM = Sc, Ti) fullerenes with six TM−N₄ or TM−B₄ units are designed. Molecular dynamic simulations confirm that the four TM₆B₂₄N₂₄ fullerenes are thermodynamically stable. Their hydrogen storage properties were investigated using density functional theory calculations. Sc/Ti atoms bind to the N₄/B₄ cavities with an average interaction energy of 6.30–11.96 eV. Hence, the problem of clustering can be avoided. 36H₂ could be adsorbed with average hydrogen adsorption energies of 0.18–0.55 eV. The lowest hydrogen desorption temperatures at atmospheric pressure for Sc₆B₂₄N₂₄(N₄)–36H₂, Sc₆B₂₄N₂₄(B₄)–36H₂, Ti₆B₂₄N₂₄(N₄)–36H₂, and Ti₆B₂₄N₂₄(B₄)–36H₂ are 255 K, 318 K, 243 K, and 408 K, respectively. The maximum hydrogen gravimetric densities of the Sc₆B₂₄N₂₄ and Ti₆B₂₄N₂₄ systems are 7.74 wt% and 7.50 wt%, respectively. Therefore, the novel Sc₆B₂₄N₂₄ and Ti₆B₂₄N₂₄ could be suitable as potential hydrogen storage materials at ambient temperature.     

Sc/Ti decorated novel C24N24 cage: Promising hydrogen storage materials

Inspired by the TM?N₄ coordination environment and the promising hydrogen adsorption property of the Ti–C₄ unit, four novel TM₆C₂₄N₂₄ (TM = Sc, Ti) cages with six TM?N₄/TM?C₄ units are designed simultaneously for the first time in this paper. Their stabilities are studied by using DFT calculations and confirmed by MD simulations. Sc₆C₂₄N₂₄(N₄) and Ti₆C₂₄N₂₄(N₄) can absorb 30 hydrogen molecules and keep the original structures intact. The average hydrogen adsorption energy is 0.13–0.26 eV for Sc₆C₂₄N₂₄(N₄)-6nH₂ (n = 1–5), and 0.09–0.23 eV for Ti₆C₂₄N₂₄(N₄)-6nH₂ (n = 1–5). The hydrogen storage capacities are 6.30 wt % and 6.20 wt %, respectively. Besides, the 30H₂ can be readily adsorbed on Sc₆C₂₄N₂₄(N₄) under 160 K and 100% desorbed at 270 K under 0.1 MPa. The desorption temperature could increase if the pressure becomes higher. Sc₆C₂₄N₂₄(C₄)/Ti₆C₂₄N₂₄(C₄) complexes are higher in energy than corresponding Sc₆C₂₄N₂₄(N₄)/Ti₆C₂₄N₂₄(N₄). They are not suitable as room-temperature hydrogen storage materials due to the structural deformation in the hydrogen storage process.     

Sc/Ti-decorated and B-substituted defective C60 as efficient materials for hydrogen storage

Doping heteroatoms and producing defects are perfect methods to improve the hydrogen storage property of TM-decorated carbon materials. In this view, four novel Sc/Ti-decorated and B- substituted defective C₆₀ fullerenes (B₂₄C₂₄) are explored. The special stability, large specific surface, uniform distribution of the metal and positively charged states make these four fullerenes have high hydrogen storage capacities. Especially, each Sc atom in Sc₆B₂₄C₂₄(B₄) can adsorb up to five H₂ molecules with a storage capacity of 6.80 wt %. The adsorbed H₂ molecules in Sc₆B₂₄C₂₄(B₄)–30H₂ begin to relax at 190 K and are 100% released at 290 K. Moreover, a comparative study is carried out for hydrogen storage properties of Sc-decorated B₄, C₄, or N₄ coordination environments. These results provide a new focus on the nature of B-, and N-substituted defective carbon nanomaterials.     

The effect of charge on the dihydrogen storage capacity of Sc2–C6H6

The effect of charge on the dihydrogen storage capacity of Sc₂–C₆H₆ has been investigated at B3LYP-D3/6-311G(d,p) level. The neutral system Sc₂–C₆H₆ can store 8H₂ with gravimetric density of 8.76 wt %, and one H₂ dissociates and bonds atomically on the scandium atom. The adsorption of 8H₂ on Sc₂–C₆H₆ is energetically favorable below 155 K. The atom-centered density matrix propagation (ADMP) molecular dynamics simulations show that Sc₂–C₆H₆ can adsorb 3H₂ within 1000 fs at 300K. Compared with Sc₂–C₆H₆, the charged systems can adsorb more hydrogen molecules with higher gravimetric density, and all the H₂ are adsorbed in the molecular form. The gravimetric densities of Sc₂–C₆H₆⁺ and Sc₂–C₆H₆²⁺ are 9.75 and 10.71 wt%. Moreover, the maximum adsorption of charged systems are favorable in wider temperature range. Most importantly, the ADMP-MD simulations indicate that Sc₂–C₆H₆²⁺ can adsorb 6 hydrogen molecules within 1000 fs at 300K. It can be found that the gravimetric density (6.72 wt%) of Sc₂–C₆H₆²⁺ still exceeds the target of US Department of Energy (DOE) under ambient conditions.     

Effect of boron substitution on hydrogen storage capacity of Li and Ti decorated naphthalene

Interaction of molecular hydrogen with Li and Ti doped boron substituted naphthalene viz. C₆B₄H₈Ti₂ and C₆B₄H₈Li₂ has been studied using density functional theory (DFT) method. The C₆B₄H₈Li₂ complex can interact with maximum of four hydrogen molecules, whereas three H₂ molecules are adsorbed on C₁₀H₈Li₂ complex. The C₆B₄H₈Ti₂ complex can interact with maximum of eight hydrogen molecules. The gravimetric hydrogen uptake capacity of C₆B₄H₈Ti₂ and C₆B₄H₈Li₂ complex is found to be 6.85 and 5.55 wt % respectively, which is higher than that of unsubstituted C₁₀H₈Ti₂ and C₁₀H₈Li₂ complexes. The boron substitution has significantly affected the hydrogen adsorption energies. The H₂ adsorption energy and Gibb's free energy corrected H₂ adsorption energy are found to be more prominent after boron substitution. The C₆B₄H₈Ti₂ and C₆B₄H₈Li₂ complexes are more stable than the respective unsubstituted C₁₀H₈Ti₂ and C₁₀H₈Li₂ complexes due to their higher binding energies. According to the atom-centered density matrix propagation (ADMP) molecular dynamics simulations C₆B₄H₈Li₂ complex retain not a single adsorbed hydrogen molecule during the simulation at room temperature, whereas five hydrogen molecules at 300 K and eight at 100 K are remain absorbed on C₆B₄H₈Ti₂ complex. The C₆B₄H₈Ti₂ complex is found to be more promising material for hydrogen storage than C₁₀B₄H₈Li₂.     

Novel sandwich-type dimetallocenes: Toward promising candidate media for high-capacity hydrogen storage

With respect to first-principles calculations, the sandwich-type dinuclear organometallic compounds as (C₅H₅)₂TM₂ (M = Sc and Ti) can adsorb up to eight hydrogen molecules. The corresponding gravimetric hydrogen-storage capacity is 6.7 wt% for (C₅H₅)₂Ti₂ and 6.8 wt% for (C₅H₅)₂Sc₂. The multimetallocenes (e.g., CpTi₃Cp and CpTi₄Cp) complexes can further increase the H₂ adsorption capacity to 8.7 wt% and 10.4 wt%, respectively. These sandwich-type organometallocenes proposed in this work are favorable for reversible adsorption and desorption of hydrogen under ambient conditions. These predictions will likely provide a new route for developing novel high-capacity hydrogen-storage materials.     

Heterofullerene C48B12-impregnated MOF-5 and IRMOF-10 for hydrogen storage: A combined DFT and GCMC simulations study

The H₂ storage properties of isoreticular metal-organic framework materials (IRMOFs), MOF-5 and IRMOF-10, impregnated with different numbers and types of heterogeneous C₄₈B₁₂ molecules were investigated using density functional theory and grand canonical Monte Carlo (GCMC) calculations. The excess hydrogen adsorption isotherms of IRMOFs at 77 K within 20 bar indicate that suitable number and type of C₄₈B₁₂ molecules play a crucial role in improving the H₂ storage properties of IRMOFs. Among the studied pure and nC₄₈B₁₂ (n = 1, 2, 4, 8) in Ci symmetry impregnating into MOF-5, at 77 K under 6 bar, MOF-5-4C₄₈B₁₂ with a 3.5 wt% and 29.9 g/L hydrogen storage density, and at 77 K under 12 bar, the pure MOF-5 with a 4.9 wt% and 31.0 g/L hydrogen storage density has the best hydrogen storage properties. Whereas, among the studied pure and nC₄₈B₁₂ (n = 1, 2, 4, 8) in S6 symmetry impregnating into IRMOF-10, IRMOF-10-8C₄₈B₁₂ always shows the best hydrogen storage properties among the pure and C₄₈B₁₂-impregnated IRMOF-10 at 77 K within 20 bar. IRMOF-10-8C₄₈B₁₂ has a 6.0 wt% and 34.6 g/L hydrogen storage density at 77 K under 6 bar, and has a 7.1 wt% and 41.4 g/L hydrogen storage density at 77 K under 12 bar. The confinement effect of IRMOFs on C₄₈B₁₂ molecules, and steric hindrance effect of C₄₈B₁₂ molecules on IRMOFs mainly affects the H₂ uptake capacity by comparing the absolute H₂ molecules in individual IRMOFs units, C₄₈B₁₂ molecules, and IRMOFs-nC₄₈B₁₂ compounds. The absolute hydrogen adsorption profiles show that eight C₄₈B₁₂ molecules impregnating into MOF-5 can exert obvious steric effects for H₂ adsorption. The saturated gravimetric and volumetric H₂ densities of IRMOF-10-8C₄₈B₁₂ higher than those of MOF-5-8C₄₈B₁₂ due to with larger free volume.     

Selective decoration of nitrogenated holey graphene (C2N) with titanium clusters for enhanced hydrogen storage application

For an envisioned hydrogen (H₂) economy, the design of new multifunctional two-dimensional (2D) materials have been a subject of intense research for the last several decades. Here, we report the thriving H₂ storage capacity of 2D nitrogenated holey graphene (C₂N), functionalized with Ti_n (n = 1–5) clusters. By using spin polarized density functional theory (DFT) calculations implemented with the van der Waals corrections, the most favourable adsorption site for the Ti_n clusters on C₂N has been revealed. With the monomer Ti, the functionalization was evenly covered on C₂N having 5% doping concentration (C₂N–Ti). For C₂N–Ti sheet, Ti binds to C₂N with a strong binding energy of ~6 eV per Ti which is robust enough to hinder any Ti–Ti clustering. Bader charge analysis reveals that the Ti_n clusters donate significant charges to C₂N sheet and become cationic to polarize the H₂ molecules, thus act as efficient anchoring agents to adhere multiple H₂ molecules. Each Ti in C₂N–Ti could adsorb a maximum of 10H₂ molecules, with the adsorption energies in the range of ?0.2 to ?0.4 eV per H₂ molecule, resulting into a high H₂ storage capacity of 6.8 wt%, which is promising for practical H₂ storage applications at room temperature. Furthermore, Ti_m (m = 2, 3, 4, 5) clusters have been selectively decorated over C₂N. However, with Ti_m functionalization H₂ storage capacities fall short of the desirable range due to large molecular weights of the systems. In addition, the H₂ desorption mechanism at different conditions of pressure and temperature were also studied by means of thermodynamic analysis that further reinforce the potential of C₂N–Ti as an efficient H₂ storage material.     

Ultra-high capacity hydrogen storage of B6Be2 and B8Be2 clusters

The B₆Be₂ and B₈Be₂ clusters, adopting fascinating inverse sandwich-like geometries, were recently predicted with quantum chemical calculations. Both systems exhibit the high stability and double aromaticity with 4σ/6π or 6σ/6π delocalized electrons. The hydrogen storage of two systems is studied in the present paper. Our calculations show that B₆Be₂ and B₈Be₂ clusters have the ultra-high capacity hydrogen storage, each Be site can bound up with seven H₂ molecules, corresponding to a gravimetric density of 25.3 wt percentage (wt%) for B₆Be₂ and 21.1 wt% for B₈Be₂, respectively, which far exceeds the target (5.5 wt%) proposed by the US department of energy (DOE) in 2017. The average absorption energies of 0.10–0.45 eV/H₂ for B₆Be₂ and 0.11–0.50 eV/H₂ for B₈Be₂ at the wB97XD level suggest that both systems are ideal for reversible hydrogen storage and release. The reversibility of H₂ molecules on B₆Be₂ and B₈Be₂ complexes are faithfully demonstrated with the Born-Oppenheimer molecular dynamics (BOMD) simulations. The Be-doped boron nanostructure is a promising candidate for ultra-high hydrogen storage materials.     

Li decorated heteroborospherene C4B32 as high capacity and reversible hydrogen storage media: A DFT study

In this work, adsorption of H₂ molecules on heteroborospherene C_2v C₄B₃₂ decorated by alkali atoms (Li) is studied by density functional theory calculations. The interaction between Li atoms and C₄B₃₂ is found to be strong, so that it prevents agglomeration of the former. An introduced hydrogen molecule tilts toward the Li atoms and is stably adsorbed on C₄B₃₂. It is obtained that Li₄C₄B₃₂ can store up to 12H₂ molecules with hydrogen uptake capacity of 5.425 wt% and average adsorption energy of ?0.240 eV per H₂. Dynamics simulation results show that 6H₂ molecules can be successfully released at 300 K. Obtained results demonstrate that Li decorated C₄B₃₂ is a promising material for reversible hydrogen storage.     

Light and stable LinB14(n=1–5) clusters for high capacity hydrogen storage at room temperature: A DFT study

In this article, we have explored the hydrogen (H₂) storage capacity of the Li doped B clusters Li_nB₁₄(n = 1–5) using density functional theory (DFT). The geometrical and Bader's topological parameters indicate that the clusters adsorb H₂ in the molecular form. The Li atom polarises the H₂ molecules for their effective adsorption on the clusters. The Li_nB₁₄ (n = 1–5) clusters are found to be stable even after H₂ adsorption at room temperature. The average adsorption energy is found to be in the range of 0.12–0.14 eV/H₂. Among the various clusters, the Li₅B₁₄ shows maximum H₂ storage capacity (13.89 wt%) at room temperature. The ADMP simulation reveals that within few femtoseconds (fs), the H₂ molecules begin to move away from the clusters and within 400 fs most of the H₂ molecules moved away from the clusters.     

Computational investigation of hydrogen storage on B6Ti3+

The structures and hydrogen storage capacities of B₆Ti₃⁺ have been theoretically investigated using DFT with PBE exchange and correlation functional. It is found that the most stable B₆Ti₃⁺01 cluster can maximally adsorb ten hydrogen molecules, which corresponds to a gravimetric uptake capacity of 8.82 wt%. The uptake capacity exceeds the 2015 target set by US Department of Energy for vehicular application. Moreover, the HOMO-LUMO gap value of B₆Ti₃⁺01 (10H₂) is larger than that of B₆Ti₃⁺01, which manifests the B₆Ti₃⁺01 will be more stable after 10H₂ adsorbed. The hydrogen adsorption energies with Gibbs free energy correction are carried out to reveal whether adsorption of hydrogen on B₆Ti₃⁺ is favorable or not at different temperatures. The results indicate that the adsorption of ten hydrogen molecules on B₆Ti₃⁺01 is energetically favorable in a fairly wide temperature range. Therefore, B₆Ti₃⁺01 is considered to be a promising material for hydrogen storage.     

Hydrogen storage in magnesium decorated boron clusters (Mg2Bn,n = 4–14): A density functional theory study

The capacity of hydrogen adsorption of magnesium (Mg) decorated small boron (B) clusters (Mg₂B_n; n = 4–14) was studied using density functional theory (DFT). The calculated results indicate that H₂ adsorbed in the molecular form. The Bader's topological analysis indicates the presence of closed shell type interaction between clusters and H₂ molecules. The clusters are stable even after the adsorption of H₂ molecules. The average energy of H₂ adsorption is calculated to be in the range of 0.13–0.22 eV/H₂. The Mg₂B₆ cluster shows maximum H₂ adsorption (8.10 wt%) at ambient temperature and pressure. Further, we have performed molecular dynamic (MD) simulation at room temperature for each cluster to understand adsorption and desorption of H₂ molecules with time. The MD simulation revealed that most of the adsorbed H₂ molecules moved away from the clusters within 200 fs. However, one H₂ molecule remains attached with the Mg₂B₁₁ cluster even after 200 fs.     

Boron substitution effect on adsorption of H2 molecules on organometallic complexes

Hydrogen adsorption properties of Be/Sc doped pentalene complexes are investigated using second ordered Møller-Plesset method (MP2). In order to study the boron substitution effect, pentalene is further modified by substituting two and four boron atoms for carbon atoms at different positions and named as TBP1 and TBP2 for two boron atom substituted structures and FBP1 and FBP2 for four boron atom substituted structures. Two H₂ molecules get adsorbed on each Be doped complex and having 3.25, 3.31, 3.31, 3.38 and 3.38 wt% H₂ uptake capacity for C₈H₆Be₂, TBP1Be₂, TBP2Be₂, FBP1Be₂ and FBP2Be₂ complexes respectively. All Sc doped pentalene and boron substituted pentalene complexes can interact with nine H₂ molecules except TBP2Sc₂ complex. The TBP2Sc₂ complex can adsorb eight H₂ molecules. The H₂ uptake capacity is found to be 8.63, 8.73, 7.84, 8.83 and 8.83 wt% for C₈H₆Sc₂, TBP1Sc₂, TBP2Sc₂, FBP1Sc₂ and FBP2Sc₂ complexes respectively. Gibbs free energy corrected adsorption energy plots show that the H₂ adsorption on all Be doped complexes is possible at all temperatures and pressures considered here. The TBP1Sc₂ complex seems to be more promising hydrogen storage material among all Sc doped complexes over a wide range of temperature and pressure. The H₂ desorption temperatures obtained for the Be doped complexes are higher than the Sc doped complexes. Stability of the complexes is predicted with the help of the gap between the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals.     

A theoretical study on cage-like clusters (C12Ti6 and C12Ti62+) for dihydrogen storage

This work reports the dihydrogen adsorption and storage capacity of cage-like clusters (C₁₂Ti₆ and C₁₂Ti₆²⁺) using density functional theory calculations. The neutral system C₁₂Ti₆ can adsorb 15 hydrogen molecules, however, some hydrogen molecules will dissociate and bond atomically on titanium atoms. The strong binding energy will cause high operating temperature to desorb hydrogen during the application process. Fortunately, the cationic system C₁₂Ti₆²⁺ can adsorb up to 16H₂ all in molecular form. Moreover, the predicted maximal hydrogen storage density is 6.96 wt% and the average adsorption energies of C₁₂Ti₆²⁺ (nH₂) (n = 1–16) are in the desirable range of reversible hydrogen storage at the 6-311G(d,p)-B3LYP and M06-2X levels. The interaction of C₁₂Ti₆²⁺ with hydrogen molecules is considered by means of the bond critical points (bcp) in the quantum theory of atoms in molecules (QTAIM). With respect to Gibbs free energy corrected H₂ adsorption energy, C₁₂Ti₆²⁺ adsorbs 16H₂ molecules should be at low temperature (190 K). These predictions show that cationic C₁₂Ti₆²⁺ is more suitable as a material for adsorbing dihydrogen.     

Geometric structures and hydrogen storage properties of M2B7 (M=Be,Mg, Ca) clusters

Based on the density functional theory, we investigate the electronic properties of the clusters M₂B₇ (M = Be, Mg, Ca) and their hydrogen storage properties systematically in this paper. Extensive global search results show that the global minimal structures of the three systems (Be₂B₇, Mg₂B₇ and Ca₂B₇) are heptagonal biconical structure, and the two alkaline earth metals are located at the top of the biconical. Chemical bonding analyses show that M₂B₇ clusters have 6σ and 6π delocalized electrons, which are doubly aromatic. At the wB97XD level, the three systems have good hydrogen storage capabilities. The hydrogen storage density of Be₂B₇ is as high as 23.03 wt%, while Mg₂B₇ and Ca₂B₇ also far exceed the hydrogen storage target set by the U.S. Department of Energy in 2017. Their average adsorption energies of H₂ molecules all ranged from 0.1 eV/H₂ to 0.48 eV/H₂, which is fall in between physisorption and chemisorption. Extensive Born Oppenheimer molecular dynamics (BOMD) simulations show that the H₂ molecules of the three systems can be completely released at a certain temperature. Therefore, M₂B₇ systems can achieve reversible adsorption of H₂ molecules at normal temperature and pressure. It can be seen that the B₇ clusters modified by alkaline earth metals may become a promising new nano-hydrogen storage material.     

C7N6 monolayer as high capacity and reversible hydrogen storage media: A DFT study

Searching advanced materials with high capacity and efficient reversibility for hydrogen storage is a key issue for the development of hydrogen energy. In this work, we studied systematically the hydrogen storage properties of the pure C₇N₆ monolayer using density functional theory methods. Our results demonstrate that H₂ molecules are spontaneously adsorbed on the C₇N₆ monolayer with the average adsorption energy in the range of 0.187–0.202 eV. The interactions between H₂ molecules and C₇N₆ monolayer are of electrostatic nature. The gravimetric and volumetric hydrogen storage capacities of the C₇N₆ monolayer are found to be 11.1 wt% and 169 g/L, respectively. High hardness and low electrophilicity provides the stabilities of H₂–C₇N₆ systems. The hydrogenation/dehydrogenation (desorption) temperature is predicted to be 239 K. The desorption temperatures and desorption capacity of H₂ under practical conditions further reveal that the C₇N₆ monolayer could operate as reversible hydrogen storage media. Our results thus indicate that the C₇N₆ monolayer is a promising material with efficient, reversible, and high capacity for H₂ storage under realistic conditions.     

Lithium clusters on graphene surface and their ability to adsorb hydrogen molecules

This research describes the theoretical study of the adsorption of lithium clusters on graphene and the ability to capture hydrogen molecules. The results of the studied structures showed that the [Li₁C₅₄H₁₈]⁺ system is capable of accepting three hydrogen molecules showing adsorption energies of 0.12 eV. On the other hand, it is important to note that in [Li_nC₅₄H₁₈] n = 2–6 systems, the lithium atoms that do not interact with the graphene surface, they can adsorb up to four hydrogen molecules. The [Li₆C₅₄H₁₈]4H₂ system presented a higher adsorption energy value of 0.31 eV. Finally, the Li–H₂ interactions were characterized by a NBO analysis, which showed that hydrogen atoms are the donors and lithium atoms are the acceptors.     

Ti decorated heterocyclic rings for hydrogen storage

This study uses first-principles calculations to investigate and compare the hydrogen storage properties of Ti doped benzene (C₆H₆Ti) and Ti doped borazine (B₃N₃H₆Ti) complexes. C₆H₆Ti and B₃N₃H₆Ti complex each can adsorb four H₂ molecules, but the former has a 0.11 wt% higher H₂ uptake capacity than the latter. Ti atoms bind to C₆H₆ more strongly than B₃N₃H₆. The hydrogen adsorption energies with Gibbs free energy correction for C₆H₆Ti and B₃N₃H₆Ti complexes are 0.17 and 0.45 eV, respectively, indicating reversible hydrogen adsorption. The hydrogen adsorption properties of C₆H₆Ti have also been studied after boron (B) and nitrogen (N) atom substitutions. Several B and N substituted structures between C₆H₆Ti and B₃N₃H₆Ti with different boron and nitrogen concentration and at different positions were considered. Initially, one boron and one nitrogen atom is substituted for two carbon atoms of benzene at three different positions and three different structures are obtained. Seven structures are possible when four carbon atoms of benzene are replaced by two boron and two nitrogen atoms at different positions. The hydrogen storage capacity of the C₆H₆Ti complex increases as boron and nitrogen atom concentrations increases. The positions of substituted boron and nitrogen atoms have less impact on H₂ uptake capacity for the same B and N concentration. The position and concentration of B and N affects the H₂ adsorption energy as well as the temperature and pressure range for thermodynamically favorable H₂ adsorption. The H₂ desorption temperature for all the complexes is found to be higher than 250 K indicates the stronger binding of H₂ molecules with these complexes.     

Hydrogen storage in scandium doped small boron clusters (BnSc2, n=3–10): A density functional study

In this work, we present the hydrogen adsorption capacity of Sc doped small boron clusters (B_nSc₂, n = 3–10) using density functional theory. Almost no structural change was observed in the host clusters after hydrogen adsorption. Stabilities of the studied clusters were confirmed by various reactivity parameters such as hardness (η), electrophilicity (ω), and electronegativity (χ). The average adsorption energies was found in the range of 0.08–0.19 eV/H₂ inferring physisorption process, and the fact is also supported by the average distance from Sc to H₂ molecules which was in the range of 2.13 Å-2.60 Å. All the clusters were found to have gravimetric density satisfying the target set by the U.S. Department of Energy (US-DOE) (5.5 wt% by 2020). From Bader's topological analysis, it was confirmed that the nature of interaction was likely to be somewhat closed shell type. ADMP molecular dynamics simulations study was performed at different temperatures to understand the adsorption and dissociation of H₂ from the complexes.