Selective adhesion of nitrogen-containing toxic gasses on hexagonal boron phosphide monolayer: a computational study.

Abstract

Context: Various toxic gasses are being released into the environment with the increasing industrialization. However, detecting these gasses at low concentrations has become one of the main challenges in environmental monitoring and protection. Thus, developing sensors with high performance to detect toxic gasses is of utmost significance. For this purpose, researchers have introduced 2D materials thanks to their unique electronic qualities and large specific surface area. Within this piece of research, a hexagonal boron phosphide monolayer (h-BPML) is employed as the substrate material. The adhesion behavior of ambient nitrogen-containing toxic gasses, i.e., N₂O, NH₃, NO₂, and NO, onto the h-BPML is investigated through DFT computations. The adhesion energy values for gasses NO and NO₂ were calculated to be - 0.509 and - 0.694 eV on the h-BPML, respectively. Meanwhile, the absorbed energy values for gasses NH₃ and N₂O were found to be - 0.326 and - 0.119 eV, respectively. The recovery time, DOS, workfunction, and Bader charges were computed based on four optimal adhesion structures. After the absorption of NO on the h-BPML, the value of workfunction of a monolayer decreased from 1.54 to 0.47 eV. This amount of decrease was the greatest among the other gasses absorbed. By comparing the investigated parameters, it can be concluded that the h-BPML has a greater tendency to interact with NO gas compared to other gasses, and it can be proposed as a sensor for NO gas.

Method: Within this piece of research, the sensitivity of the h-BPML to four nitrogenous toxic gasses, namely, N₂O, NH₃, NO₂, and NO, was investigated using the DFT with HSE06 hybrid functional by using GAMESS software. For this purpose, we computed the DOS, workfunction, and the Bader charges for the four adhesion systems with most stability.