H₂ adsorption and diffusion behaviors on partially oxidized TiZrV non-evaporable getter film studied using density functional theory

The improvement of vacuum performance and stability in particle accelerators relies on non-evaporable getters, with TiZrV non-evaporable getter widely used in vacuum chambers. TiZrV non-evaporable getter sorbs residual active gases and reduces pressure in the vacuum chamber. This paper investigates the H₂ adsorption and diffusion mechanisms on partially oxidized TiZrV non-evaporable getter using density functional theory. Results show that H₂ adsorption and dissociation prefer the TiZrV surface, with electron transfer from TiZrV to H₂ molecules. The lowest adsorption energy is −1.756 eV at the TiZrV hollow site. H₂ is more likely to dissociate near unoxidized metal, bonding with surrounding atoms, while oxidation inhibits H₂ cleavage adsorption. Additionally, H₂ diffusion into TiZrV bulk occurs without energy barriers, making it an easy process. This study provides insights into H₂ adsorption on TiZrV non-evaporable getter mechanism, explaining its excellent performance.