Adsorption of 13 Gases on h-Be₂P₄ Nanosheet and Its Possibility to Effectively Detect Toxic Gases

Sensor materials with significant sensitivity, selectivity, and limit of detection (LOD) play a crucial role in monitoring and control of industrial process and environmental pollution. Herein density functional theory and ab initio molecular dynamics simulation are used to identify a hexagonal Be₂P₄ (h-Be₂P₄) monolayer as a new sensor material for toxic gases. Adsorption properties of 10 target gases (CO, NO, NO₂, SO₂, H₂S, NH₃, PH₃, AsH₃, COCl₂, and HCN) and three environmental gases (N₂, CO₂, and H₂O) are investigated. The results demonstrate that the h-Be₂P₄-based sensor behaves with significant sensitivity, high selectivity, short recovery time, and fine adsorption stability for all target gases in the presence of CO₂ and N₂. The presence of H₂O decreases the selectivity partially. Nevertheless, the LODs imply that the h-Be₂P₄-based sensor can only detect six target gases in increased LOD order: NO₂< NH₃< HCN < SO₂< CO < PH₃ at 298.15 K. The low detection limits are found to be 7.3 × 10^-10, 2.14 × 10^-6, and 14 ppm for NO₂, NH₃, and HCN, respectively, which are substantially lower than half of the corresponding immediately dangerous to life or health (IDLH) limits, demonstrating an excellent sensor performance to detect NO₂, NH₃, and HCN.