Investigating the catalytic activity of Mgn (n = 4–8) clusters for the hydrogen evolution reaction using density functional theory

To efficiently desorb H2, pure Mgn (n = 4–8) clusters were chosen for the hydrogen evolution reaction with H2O. At the PBE0/def2‐TZVP level and the PBE0‐D3/def2‐TZVP level, the lowest energy structures of Mgn (n = 4–8) clusters and the most stable structures of Mgn@H2O (n = 4–8) complexes were searched in the local region. The transition state was predicted, and then the hydrogen evolution reaction channel was obtained by using the intrinsic reaction coordinate (IRC) to confirm the transition state. To better analyze the hydrogen reaction mechanism, the character of Mgn@H2O (n = 4–8) complexes and MgnO (n = 4–8) clusters, as well as the atomic charge change trend, were investigated using interaction region indicator function analysis (IRI) and natural population analysis (NPA). The reaction effect of Mg4 cluster and H2O is the worst. The energy barrier does, however, progressively lower as the cluster atom count rises, improving the reaction effect. We catalyzed water molecules using Mgn (n = 4–8) clusters to produce hydrogen gas. The Mg8 cluster exhibits the best hydrogen evolution effect, as can be seen by comparing the energy barrier diagram, and the hydrogen molecules are fully precipitated, as can be shown by examining the IRI diagram.