Mg(12)O(12) and Be(12)O(12) Nanocages as Sorbents and Sensors for H(2)S and SO(2) Gases: A Theoretical Approach

Theoretical calculations based on the Density Functional Theory (DFT) have been performed to investigate the interaction of H(2)S as well SO(2) gaseous molecules at the surfaces of Be(12)O(12) and Mg(12)O(12) nano-cages. The results show that a Mg(12)O(12) nano-cage is a better sorbent than a Be(12)O(12) nano-cage for the considered gases. Moreover, the ability of SO(2) gas to be adsorbed is higher than that of H(2)S gas. The HOMO–LUMO gap (E(g)) of Be(12)O(12) nano-cage is more sensitive to SO(2) than H(2)S adsorption, while the E(g) value of Mg(12)O(12) nano-cage reveals higher sensitivity to H(2)S than SO(2) adsorption. The molecular dynamic calculations show that the H(2)S molecule cannot be retained at the surface of a Be(12)O(12) nano-cage within 300–700 K and cannot be retained on a Mg(12)O(12) nano-cage at 700 K, while the SO(2) molecule can be retained at the surfaces of Be(12)O(12) and Mg(12)O(12) nano-cages up to 700 K. Moreover, the thermodynamic calculations indicate that the reactions between H(2)S as well SO(2) with Be(12)O(12) and Mg(12)O(12) nano-cages are exothermic. Our results suggest that we can use Be(12)O(12) and Mg(12)O(12) nano-cages as sorbents as well as sensors for H(2)S and SO(2) gases.