MOLECULAR DYNAMICS SIMULATION OF THE FORMATION MECHANISM OF MOLECULAR HYDROGEN UNDER PROTON IRRADIATION IN THE ANATASE TIO₂ CRYSTAL STRUCTURE

The photocatalytic properties of TiO₂ crystals in the nano-sized anatase phase are more active than those of TiO₂ in the rutile phase [1]. It is known that the photocatalytic activity peaks at 5 nm in the anatase crystal structure and 2.5 nm in the rutile structure. Additionally, when using anatase TiO₂ crystals as a catalyst for molecular hydrogen production, a high chemical yield of H₂ is observed [2]. The deeply excited charge carriers in the electronic structure of TiO₂ also contribute to the reactions occurring on the surface of the anatase phase. Furthermore, a theoretical basis for the formation of molecular hydrogen through the Me-(H-H)ₙ-Me structure under H⁺ ion irradiation has been developed [3]. However, the limited number of experiments and in-situ studies do not fully capture the physical nature of the process. For this purpose, using interatomic potentials (simultaneous representation of metallic, covalent, and ionic bonds) determined for the anatase TiO₂ crystal structure, a molecular dynamics simulation was conducted to describe the mechanism of molecular hydrogen formation under high-energy proton irradiation. Additionally, the temperature distribution radius during the interaction within the structure was determined.