SnO–Sn(3)O(4) heterostructural gas sensor with high response and selectivity to parts-per-billion-level NO(2) at low operating temperature

Considering the harmfulness of nitrogen dioxide (NO(2)), it is important to develop NO(2) sensors with high responses and low limits of detection. In this study, we synthesize a novel SnO–Sn(3)O(4) heterostructure through a one-step solvothermal method, which is used for the first time as an NO(2) sensor. The material exhibits three-dimensional flower-like microparticles assembled by two-dimensional nanosheets, in situ-formed SnO–Sn(3)O(4) heterostructures, and large specific surface area. Gas sensing measurements show that the responses of the SnO–Sn(3)O(4) heterostructure to 500 ppb NO(2) are as high as 657.4 and 63.4 while its limits of detection are as low as 2.5 and 10 parts per billion at 75 °C and ambient temperature, respectively. In addition, the SnO–Sn(3)O(4) heterostructure has an excellent selectivity to NO(2), even if exposed to mixture gases containing interferential part with high concentration. The superior sensing properties can be attributed to the in situ formation of SnO–Sn(3)O(4) p–n heterojunctions and large specific surface area. Therefore, the SnO–Sn(3)O(4) heterostructure having excellent NO(2) sensing performances is very promising for applications as an NO(2) sensor or alarm operated at a low operating temperature.