Hydrogen evolution reaction of Be + H₂O (n = 5-9) based on density functional theory

The structural evolution of Be clusters with n = 5-9, the adsorption energy created by the Be@H₂O (n = 5-9) complex, and the mechanism of the hydrogen evolution reaction of Be + H₂O (n = 5-9) were all studied using DFT calculations based on the PBE0-D3/Def2TZVP level. Excluding the Be₇ cluster, the global minimum structures of beryllium clusters with n = 5-9 showed a higher point group pair formation. Be₇ clusters' high point group symmetry is unstable. Be₉@H₂O released the greatest energy during the complex's creation (-1.45 eV). Exothermic hydrogen evolution occurs in Be + H₂O (n = 5-9), and all transition states, intermediate stages, and products have energies lower than the equilibrium constant (EC). More energy is released when an O-H bond in the Be@H₂O (n = 5-9) complex is broken, and the energy release results in a change in the cluster structure, which is more pronounced in the Be₇ + H₂O reaction. Interestingly, there are eight transition states in the Be₆ + H₂O hydrogen evolution reaction, with the second O-H bond break requiring more energy than the first. There are only three transition states in the Be₈ + H₂O hydrogen evolution reaction, and the reaction energy is the greatest (-4.13 eV).