Activation of Molecules H₂ on Platinum and Platinovanadium Clusters: Quantum-Chemical DFT Modeling

Abstract

The NEB DFT/PBE0/def2tzvp quantum-chemical method with the construction of minimum energy paths (MEP) was used to study the activation of H2 molecules by Pt4 and Pt3V clusters. It is shown that, in the case of Pt4 and Pt3V clusters, barrier-free dissociative adsorption of H2 molecules occurs on platinum centers, while molecular adsorption of hydrogen occurs on the vanadium atom in Pt3V with a slight weakening of the H–H bond, but without its breaking. The noted features of the coordination of H2 molecules are explained at the level of the MO method. It has been established that the migration of the H atom from one cluster metal center to another in the considered model clusters, as, possibly, in the phenomenon of hydrogen spillover, occurs at small activation barriers in the direction of the displacement vector corresponding to the normal vibration of the system in the transition state. In the process of hydrogen migration, a significant role of Pt–H–Pt and V–H–Pt bridging groups, which facilitate the transition of H atoms from one metal center of the cluster to another, has been revealed.