First-principles Study on α/β/γ-FeB 6 Monolayers as Potential Gas Sensor for H 2 S and SO 2

Abstract

The adsorptions of toxic gases SO2 and H2S on 2D α/β/γ-FeB6 monolayer were investigated using density functional theory calculations. To analyze the interaction between gas molecule H2S/SO2 and α/β/γ-FeB6 monolayer, we calculated adsorption energy, adsorption distance, Mullikan charge, charge density difference, band structure, density of states, work function and theoretical recovery time. The adsorption energies show that H2S/SO2 is chemisorbed on α/β-FeB6 while H2S/SO2 is physiosorbed on γ-FeB6 monolayer. As a result, γ-FeB6 has short recover time for H2S (3.40×10− 4 s)/SO2 (5.09×10− 3 s) due to modest adsorption. Therefore, γ-FeB6 may be a promising candidate for reusable H2S/SO2 sensor at room temperature. Although H2S is chemisorbed on α/β-FeB6, as the working temperature rises to 500 K, the recovery time of α/β-FeB6 for H2S can decrease to 1.34×10− 2 s and 5.23×10− 1 s, respectively, which are well within the detectable range. So, α/β-FeB6 monolayer also may be good candidate for H2S gas sensor.