Electronic and gas sensing properties of ultrathin TiO2 quantum dots: A first-principles study

Clean air is essential for a sustainable and healthy human settlement. Hazardous gases produced by industry ruin the air quality, thus it is crucial to find efficient treatment methods. The capability of ultrathin TiO2 quantum dots to adsorb different gases, namely CO, CO2 , SO2 , H2S, NO2 , NH3, and O3 , are investigated using DFT cal-culations. Based on electronic properties and molecular electrostatic potential, edge Ti-atoms are highly inter-active and are suitable active sites for gas adsorption. Adsorption energy, charge transfer, and atom in molecule analysis confirm that all the considered gases are successfully absorbed. The UV-Vis spectrum experience redshift /blueshift after adsorption of (CO, CO2 , H2S, NH3)/(H2S, O3) and thus can be used to test the adsorption process. These favorable adsorption properties and the calculated quick recovery time make the two-dimensional TiO2 quantum dots potential candidates for efficient and reusable gas sensors.