A highly selective gas sensor based on the WO3/WS2 van der Waals heterojunction for the 2-chloroethyl ethyl sulfide (2-CEES) sensing application

Abstract

In the process of organic synthesis, some toxic and harmful gases are sometimes used and produced. The leakage of these gases is extremely harmful to human health and the environment. Realizing highly selective detection of toxic gas is very important, as it can prevent the potential hazardous effect of the toxic gas. This work is an attempt to produce highly selective sensing materials for detecting 2-chloroethyl ethyl sulfide (2-CEES, dichlorodiethyl sulfide simulation). A novel WO₃/WS₂ van der Waals heterostructured material is controllably constructed by simply annealing WS₂ nanosheets in air. Through the optimization of the oxidation temperature, it is found that a gas sensor based on the WO₃/WS₂ composite material (annealing at a temperature of 500 °C for 1 hour) exhibits excellent sensing performance in the detection of 2-CEES. In more detail, the sensor has a response of 81% to 5.7 ppm 2-CEES at an optimal operating temperature of 240 °C, a rapid response/recovery time (20 s/55 s), excellent reproducibility and satisfactory stability. Most importantly, the sensor shows high selectivity to 2-CEES compared with ammonia, common VOC gases (acetone and ethanol) and other toxic gas simulation gases [dimethyl methylphosphonate (DMMP), dichloromethane and acetonitrile]. The above-mentioned excellent sensing performance makes WO₃/WS₂ a potential sensing material for dichlorodiethyl sulfide.