A DFT Study on Be_n(n = 10-12) Clusters with Hydrogen Storage Capacity

Hydrogen energy has garnered widespread attention as a clean energy source. This study employs density functional theory (DFT) to systematically investigate the hydrogen storage performance of Be_n(n = 10-12) clusters. The results reveal that hollow spherical Be_n clusters exhibit excellent hydrogen storage capacity while maintaining good thermal stability even after H₂ adsorption at room temperature. Specifically, Be₁₀, Be₁₁ and Be₁₂ clusters can adsorb 26, 28, and 30 H₂ molecules, achieving hydrogen storage densities of 31.96 wt%, 31.87 wt%, and 35.87 wt%, respectively-far exceeding the U.S. Department of Energy's target of 5.5 wt%. Calculations indicate an average adsorption energy between 0.16 and 0.19 eV/H₂, which lies between physisorption and chemisorption. IGMH isosurface analysis confirms the physisorption characteristics of H₂ molecules. PDOS analysis reveals that the hydrogen storage mechanism primarily originates from H₂ molecular polarization and van der Waals forces arising from orbital hybridization between hydrogen atoms and the substrate. Desorption temperature calculations show that, above 216 K, this material demonstrates potential for reversible hydrogen storage. This study demonstrates that these three hollow spherical beryllium cluster systems are ideal candidates for achieving ultra-high-capacity reversible hydrogen storage.