Gold-loaded tellurium nanobelts gas sensor for ppt-level NO2 detection at room temperature

NO2 is one of the recognized six major pollutants worldwide. Its monitoring and forewarning are indispensable for human health. Thus, a practical sensor with rapid response and high sensitivity would endow us with an effective acknowledgment of NO2 distribution. In this work, the gold-loaded tellurium (Au@Te) nanobelts are synthesized through a one-pot hydrothermal process. According to various characterization, including X-ray diffraction, atomic force microscope, transmission electron microscopy, the formation of tellurium nanobelts with a typical thickness of 18 nm and flower-like gold nanoparticles with a diameter of 50–200 nm is confirmed. Based on these, the Au@Te sensor exhibits appealing sensing properties in a comprehensive measurement considering the practical application scenarios, including a sensitivity of 0.028 ppb-1 (0–50 ppb), a limit of detection with ppt-level (~83 ppt), rapid response (11.3 s towards 5 ppm), good repeatability and selectivity. Meanwhile, the long-term stability is measured under continuous charging in accordance with actual application scenarios. A stable response along 28 days is observed. This work provides an efficient strategy for the fabrication of NO2 sensors, together with a case for gas sensor evaluation towards specified application scenarios.