Selective sensing of NH3 and CH2O molecules by novel 2D porous hexagonal boron oxide (B3O3) monolayer: A DFT approach

Abstract

DFT computations are used for the adsorption of different gasses like NH3, CO, CO2, CH2O, PH3, H2S, H2O, SO2, NO, NO2, HCN, CH4, COCl2, N2O, NF3, NCl3, O3 and H2 onto porous hexagonal boron oxide monolayer (ph-BOL) to explore its potentials for gas sensing. The negative adsorption energies (-1.00 to -10.13 kcal/mol) for all complexes demonstrates that adsorption of various gas molecules over the ph-BOL monolayer is energetically favorable and exothermic process. The energy gap (Egap) results shows that highest decreased in Egap occurred for NH3@ph-BOL (1.671 eV) and CH2O@ph-BOL (1.875 eV), respectively. This indicates the selectivity and sensitivity of ph-BOL toward these analytes. The non-covalent interaction, reduced density gradient and atom in molecules analysis for NH3@ph-BOL and CH2O@ph-BOL justified the presence of non-covalent electrostatic interactions and van der Waals interactions in the resulted complexes. The electron density difference and natural bond orbital analyses reveals that there is significant charge shifting occurred between the analytes and ph-BOL monolayer. The SAPT0 energy components values are well agreed with the interaction energies. Moreover, the AIMD study reveal that the complexes are stable even at 500 K. The recovery time of ph-BOL sensor for NH3 molecule and CH2O molecule detection is estimated to be 1.6 × 10−6 s and 8.1 × 10−7 s, respectively, suggested that the regeneration of sensor is so rapid at room temperature. Thus, ph-BOL is a potent candidate for NH3 and CH2O molecules detection and will promote experimetnalist to designed an efficent gas sensor.