First principle study of transition metals codoped MoS2 as a gas sensor for the detection of NO and NO2 gases

Exposure to nitrogen oxides (NOx) has been reported to seriously affect the respiratory systems. More precisely, breathing NOx may lead to the appearance of asthma symptoms, and may also result in the infection with asthma over long intervals. This study is devoted to finding novel systems to detect nitric oxide (NO) and nitrogen dioxide (NO2) with improved sensitivity. Consequently, gold (Au) and silver (Ag) codoped molybdenum disulfide (MoS2) (Au–Ag–MoS2) is proposed as NO and NO2 gas sensor based on density functional theory (DFT) calculations. The variations of the electronic properties as well as the adsorption parameters of the new proposed sensor upon the adsorption of NO and NO2 gases are compared with pristine, Au-doped, and Ag-doped MoS2. The results reflect a remarkable change in the band gap of the developed systems upon the adsorption of NO and NO2 gases. Meanwhile, the adsorption parameters demonstrate that the Au doped MoS2 system is selective to NO, while the codoped MoS2 system is selective to NO2. Specifically, the Au-doped MoS2 exhibits its maximum adsorption energy (Eads) towards NO of −0.721 eV. Moreover, the highest adsorption energy and charge transfer (ΔQ) are found to be −2.603 eV and 0.448 e, respectively, for the case of NO2/Au–Ag-codoped MoS2. Hence, our investigation suggests that Au–Ag-codoped MoS2 can be utilized as a gas sensor for the detection of NO2 gas.