Abstract
The hydrogen absorption behavior of C15 Laves phase compounds ZrV2 has been systematically investigated by the first-principles calculations. In the C15 Laves phase, hydrogen atoms can occupy three possible tetrahedral interstitial positions—2A2B, 1A3B, and 4B—in which the 2A2B site, being the largest interstitial space among the three possible positions, is the most favorable interstitial site. In addition, 2A2B and 1A3B sites can form some ordered clathrate-type structures to provide diffusion paths for hydrogen atoms to move inside the ZrV2 compounds. According to the calculated barrier energies of H atoms in different diffusion paths in ZrV2, it is found that hydrogen atoms prefer intra-ring diffusion to inter-ring diffusion, although inter-ring diffusion provides a non-negligible contribution to the overall H diffusion process. However, the existence of 1A3B sites can facilitate the diffusion of hydrogen atoms in adjacent six-membered rings. Finally, the absorption energies and electronic structures of ZrV2Hx (x = 0.5, 1, 2, 3, 4, 6, 7, and 12) were computed, and the results show that the hydrogen content reaches its maximum on the condition of 6 < x < 7. Moreover, hydrogen atoms make a stronger covalent bond with V atoms than with Zr atoms.
Highlights
With the rapid development of electronic technology, obtaining better vacuum conditions has become one of the essential requirements in the research and development (R&D) of electric vacuum devices
According to the calculated barrier energies of H atoms in different diffusion paths in ZrV2, it is found that hydrogen atoms prefer intra-ring diffusion to inter-ring diffusion, inter-ring diffusion provides a non-negligible contribution to the overall H diffusion process
In the AB2 Laves phases, there are three types of tetrahedral interstitial sites: the 2A2B site formed by two A atoms and two B atoms, the 1A3B site formed by one A atom and three B atoms, and the 4B site formed by four B atoms, which correspond to the 96g, 32e, and 8b Wyckoff sites, respectively
Summary
With the rapid development of electronic technology, obtaining better vacuum conditions has become one of the essential requirements in the research and development (R&D) of electric vacuum devices. Because the use of getter materials that can absorb H2 and other active gases would be an effective solution to achieve the desired vacuum degree and ensure the long-term stability and reliability of such devices, various getter materials are of major interest for hydrogen adsorption and have been extensively investigated.. One type of promising hydrogen absorption material is AB2type intermetallic compounds with a Laves phase-type structure, which can establish stable hydrogen reactions relative to the hydrides of the component metals. The favorable interstitial sites and diffusion behavior of H atoms within the ZrV2 lattice, as well as the stability and electronic structure of ZrV2Hx (x = 0.5, 1, 2, 3, 4, 6, 7, and 12), were systematically investigated using the first-principles calculations. The aim is to conduct a comprehensive study on the hydrogen absorption behavior of ZrV2 compounds and provide beneficial theoretical support for further experimental studies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
