Selective decorating of BC_3 and C_3N nanosheets with single metal atom for hydrogen storage

摘要

Employing first-principles calculations, we have studied the structure, stability and hydrogen storage efficiency of pristine and defective BC_3 and C_3N monolayer functional-ized by a variety of single metal adatoms. It is found that single Sc adatom, acting as an optimal dopant on perfect BC_3 monolayer, is able to adsorb up to nine H_2 molecules as strongly as around 0.24 eV/H_2, which allows for a hydrogen storage capacity of 7.19 wt for Sc atoms stably adsorbing on double sides of BC_3 monolayer with eighteen H_2 molecules (18H_2@2Sc/BC_3). Moreover, the desorption temperature and thermodynamical stability of multiple H_2 adsorbed Sc-decorated BC_3 sheet have been addressed and the saturate configuration of 18H_2@2Sc/BC_3 is predicted to be stable at mild temperatures and pressures, i.e. less than 250 K at 1 bar, or larger than 24 bar at room temperature. This study indicates that the Sc-decorated BC_3 monolayer could be a potential H_2 storage candidate, and provides an instructive guidance for designing metal-functionalized carbon-based sheets in hydrogen storage.