MgO and BeO Nanocages as Sorbents and Sensors for HS and SO Gases: A Theoretical Approach.

Theoretical calculations based on the Density Functional Theory (DFT) have been performed to investigate the interaction of HS as well SO gaseous molecules at the surfaces of BeO and MgO nano-cages. The results show that a MgO nano-cage is a better sorbent than a BeO nano-cage for the considered gases. Moreover, the ability of SO gas to be adsorbed is higher than that of HS gas. The HOMO-LUMO gap (E) of BeO nano-cage is more sensitive to SO than HS adsorption, while the E value of MgO nano-cage reveals higher sensitivity to HS than SO adsorption. The molecular dynamic calculations show that the HS molecule cannot be retained at the surface of a BeO nano-cage within 300-700 K and cannot be retained on a MgO nano-cage at 700 K, while the SO molecule can be retained at the surfaces of BeO and MgO nano-cages up to 700 K. Moreover, the thermodynamic calculations indicate that the reactions between HS as well SO with BeO and MgO nano-cages are exothermic. Our results suggest that we can use BeO and MgO nano-cages as sorbents as well as sensors for HS and SO gases.