Ag nanoparticles sensitized ZnO/MoS2 composites to detect ppb-level NO2 and automobile exhaust gas

Increasing car ownership and industrialization will undoubtedly increase the amount of NO2 in the atmosphere, which is immeasurably harmful to the environment and human body. However, the development of sensors capable of rapidly detecting NO2 at ppb-level and with excellent resistance to humidity remains a great challenge. Here, we prepared Ag@ZnO/MoS2 composites by hydrothermal method, photodeposition and calcination at specific temperature. The obtained composites showed a flower-like structure. The gas sensing performance tests showed that the Ag@ZnO/MoS2 sensor has the highest response to 100 ppm-100 ppb NO2 at 130 degrees C, short response/recovery time (2.5/3 s), low theoretical detection limit (36 ppb) and excellent humidity resistance. This may be attributed to the construction of heterojunctions and the catalytic effect of Ag nanoparticles. In addition, we have successfully applied Ag@ZnO/MoS2 sensor to automobile exhaust gas detection, which provides new insights into the development of portable automobile exhaust gas detection sensors.