8.
The effect of charge on the dihydrogen storage capacity of Sc
2–C
6H
6 has been investigated at B3LYP-D3/6-311G(d,p) level. The neutral system Sc
2–C
6H
6 can store 8H
2 with gravimetric density of 8.76 wt %, and one H
2 dissociates and bonds atomically on the scandium atom. The adsorption of 8H
2 on Sc
2–C
6H
6 is energetically favorable below 155 K. The atom-centered density matrix propagation (ADMP) molecular dynamics simulations show that Sc
2–C
6H
6 can adsorb 3H
2 within 1000 fs at 300K. Compared with Sc
2–C
6H
6, the charged systems can adsorb more hydrogen molecules with higher gravimetric density, and all the H
2 are adsorbed in the molecular form. The gravimetric densities of Sc
2–C
6H
6+ and Sc
2–C
6H
62+ are 9.75 and 10.71 wt%. Moreover, the maximum adsorption of charged systems are favorable in wider temperature range. Most importantly, the ADMP-MD simulations indicate that Sc
2–C
6H
62+ can adsorb 6 hydrogen molecules within 1000 fs at 300K. It can be found that the gravimetric density (6.72 wt%) of Sc
2–C
6H
62+ still exceeds the target of US Department of Energy (DOE) under ambient conditions.
相似文献