A sensitive ppb-level NO2 sensor based on SnO2 decorated Te nanotubes

The gas pollutant of Nitrogen dioxide (NO 2 ) can have a severe impact on human respiratory systems, with a potential threat to human health. Therefore, a NO 2 sensor is necessary to be implemented to have the information on exhaled low concentrations of NO 2 emitted from different sources. In this work, the tellurium nanotubes (Te NT) based heterojunction with SnO 2 nanoparticles (TeNT/SnO 2 ) for detecting ppb-level NO 2 at room temperature was developed. The TeNT /SnO 2 sensor exhibits a better response (25.3 %), and faster response time (32 s) to 600 ppb of NO 2 in comparison to pristine Te NT based sensors (7.9 % and 154 s). The promoted sensing properties including selectivity, signal repeatability, and long-term stability could be attributed to the formation of TeNT/SnO 2 heterojunctions. The density function theory (DFT) in accordance with the first principle was conducted to calculate the adsorption ability of the TeNT/SnO 2 heterojunctions. It indicates that the TeNT/SnO 2 heterojunctions facilitated the adsorption of oxygen (-0.635 eV) and NO 2 (-1.533 eV) in comparison to Te NT.