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

Abstract

Exposure to nitrogen oxides (NO x ) has been reported to seriously affect the respiratory systems. More precisely, breathing NO x 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 (NO 2 ) with improved sensitivity. Consequently, gold (Au) and silver (Ag) codoped molybdenum disulfide (MoS 2 ) (Au–Ag–MoS 2 ) is proposed as NO and NO 2 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 NO 2 gases are compared with pristine, Au-doped, and Ag-doped MoS 2 . The results reflect a remarkable change in the band gap of the developed systems upon the adsorption of NO and NO 2 gases. Meanwhile, the adsorption parameters demonstrate that the Au doped MoS 2 system is selective to NO, while the codoped MoS 2 system is selective to NO 2 . Specifically, the Au-doped MoS 2 exhibits its maximum adsorption energy (E ads ) towards NO of −0.721 eV. Moreover, the highest adsorption energy and charge transfer ( Δ Q) are found to be −2.603 eV and 0.448 e, respectively, for the case of NO 2 /Au–Ag-codoped MoS 2 . Hence, our investigation suggests that Au–Ag-codoped MoS 2 can be utilized as a gas sensor for the detection of NO 2 gas. • MoS 2 sensor materials were investigated for NO and NO 2 sensors using DFT calculation. • The effect of codoping of MoS 2 by Au and Au on adsorption of NO and NO 2 gases was investigated. • The response was analyzed using: adsorption energy and distance, band structure, density of states, and charge transfer. • Doping enhanced of the adsorption energy towards both NO and NO 2 gases. • The adsorption energy and charge transfer were maximum for the NO 2 /Au-Ag-codoped MoS 2 .