M-Encapsulated Be 12 O 12 Nano-Cage (M = K, Mn, or Cu) for CH 2 O Sensing Applications: A Theoretical Study.

DFT and TD-DFT studies of B3LYP/6-31 g(d,p) with the D2 version of Grimme's dispersion are used to examine the adsorption of a CH 2 O molecule on Be 12 O 12 and MBe 12 O 12 nano-cages (M = K, Mn, or Cu atom). The energy gap for Be 12 O 12 was 8.210 eV, while the M encapsulation decreased its value to 0.685-1.568 eV, whereas the adsorption of the CH 2 O gas decreased the E g values for Be 12 O 12 and CuBe 12 O 12 to 4.983 and 0.876 eV and increased its values for KBe 12 O 12 and MnBe 12 O 12 to 1.286 and 1.516 eV, respectively. The M encapsulation enhanced the chemical adsorption of CH 2 O gas with the surface of Be 12 O 12 . The UV-vis spectrum of the Be 12 O 12 nano-cage was dramatically affected by the M encapsulation as well as the adsorption of the CH 2 O gas. In addition, the adsorption energies and the electrical sensitivity of the Be 12 O 12 as well as the MBe 12 O 12 nano-cages to CH 2 O gas could be manipulated with an external electric field. Our results may be fruitful for utilizing Be 12 O 12 as well as MBe 12 O 12 nano-cages as candidate materials for removing and sensing formaldehyde gas.