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

To efficiently desorb H 2 , pure Mg n ( n = 4–8) clusters were chosen for the hydrogen evolution reaction with H 2 O. At the PBE0/def2‐TZVP level and the PBE0‐D3/def2‐TZVP level, the lowest energy structures of Mg n ( n = 4–8) clusters and the most stable structures of Mg n @H 2 O ( 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 Mg n @H 2 O ( n = 4–8) complexes and Mg n O ( 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 Mg 4 cluster and H 2 O is the worst. The energy barrier does, however, progressively lower as the cluster atom count rises, improving the reaction effect.