Adsorption and sensing performance of air pollutants on a β-TeO₂ monolayer: a first-principles study

Two-dimensional (2D) β-TeO₂ is a novel semiconductor with potential applications in electronic circuits due to its air-stability and ultra-high carrier mobility. In this study, we explore the possibility of using a 2D β-TeO₂ monolayer for the detection of gaseous pollutants including SO₂, NO₂, H₂S, CO₂, CO, and NH₃ gas molecules based on first-principles calculations. The adsorption properties including the adsorption energy, adsorption distance and charge transfer indicate that the interaction between 2D β-TeO₂ and the six gases is via a physisorption mechanism. Among the six gas adsorption systems, the SO₂ adsorption system has the most negative adsorption energy and the largest charge transfer. In addition, the adsorption of SO₂ obviously changes the electrical conductivity of the β-TeO₂ monolayer because the band gap decreases from 2.727 eV to 1.897 eV after adsorbing SO₂. Our results suggest that the 2D β-TeO₂ should be an eminently promising SO₂ sensing material.