The effect of charge on the dihydrogen storage capacity of Sc2-C6H6

The effect of charge on the dihydrogen storage capacity of Sc-2-C6H6 has been investigated at B3LYP-D3/6-311G(d,p) level. The neutral system Sc-2-C6H6 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-C6H6 is energetically favorable below 155 K. The atom-centered density matrix propagation (ADMP) molecular dynamics simulations show that Sc-2-C6H6 can adsorb 3H(2) within 1000 fs at 300K. Compared with Sc-2-C6H6, 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-C6H6+ and Sc-2 -C6H62+ 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-C6H62+ can adsorb 6 hydrogen molecules within 1000 fs at 300K. It can be found that the gravimetric density (6.72 wt%) of Sc-2-C6H62+ still exceeds the target of US Department of Energy (DOE) under ambient conditions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study investigates the effect of charge on the dihydrogen storage capacity of Sc-2-C6H6, finding that charged systems can adsorb more hydrogen molecules with higher gravimetric density across a wider temperature range. ADMP-MD simulations show that Sc-2-C6H62+ can adsorb 6 hydrogen molecules within 1000 fs at 300K, exceeding the target of the US Department of Energy under ambient conditions.