Be2C monolayer as an efficient adsorbent of toxic volatile organic compounds: theoretical investigation

Abstract

In this study, the adsorption and sensing of four volatile organic compounds (VOCs) including CH2O, CH3CHO, CH2ClCHO, and C6H6 by a two-dimensional (2D) Be2C monolayer are investigated, theoretically. The adsorption of the VOCs in their isolated form and the co-adsorption of each VOC and a water molecule have also been studied, separately. The calculated adsorption energies (E ad) of the selected VOCs in the absence of the water molecule are −1.34, −0.84, −0.46, and −0.76 eV, respectively, indicating the good affinity of the Be2C monolayer for the adsorption of the VOCs. The calculated co-adsorption energies of the selected VOCs are −1.82, −0.99, −0.53, and (−0.67 and −0.82) eV, respectively. The quantum theory of atoms in molecules (QTAIM) is used to determine the interatomic interaction paths between the selected VOCs and the Be2C monolayer. The calculated natural bonding orbital (NBO) charges and the electron density difference maps of the complexes (monlayer + adsorbate) show the charge transfer from the adsorbed molecules to the Be2C monolayer except for CH2O. The potential of the Be2C monolayer for the sensing of the selected VOCs, is investigated by calculating the absorption spectra of the complexes and comparing them with the absorption spectrum of the bare Be2C monolayer.