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

Abstract

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 °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.