DTT graphene: A novel Dirac semimetal with ultrahigh reversible hydrogen storage capacity

In this work, we predicted a new Dirac semimetal, named DTT graphene, composed of decagon, tetragon and tetragon carbon rings. Based on first-principles calculations, we explored the hydrogen storage performance of the alkali metals (Li, Na, K) and alkali-earth metal (Ca) decorated DTT graphene. Remarkably, the metals Li, Na, K and Ca can be strongly bound on DTT graphene with large binding energy instead of forming clusters. And single Li, Na, K and Ca decorated DTT graphene can reach H2 uptake of 12.3 wt%, 12.0 wt%, 11.8 wt%, and 11.7 wt%, respectively, which significantly exceeds the DoE standard (6.5 wt%). Finally, the ab-initio molecular dynamics calculations at corresponding H2 desorption temperature verify the feasibility of metallized DTT graphene as a reversible hydrogen storage medium. And these findings are also expected to advance experimental studies.