MoS2 doping for enhanced H2S detection

Resistive gas sensors based on sheets of MoS2 were shown to achieve excellent sensitivity and high selectivity of detection for NO2 and NH3. However, due to the low electric response of the sheet to other molecules, the number of compatible analytes is limited. Hence, this work investigates, employing density functional theory calculations, doping of MoS2 for enhanced H2S detection. The study follows an experimental model of MoS2 doping facilitated via electron irradiation and uses P, Cl, and Ge dopants. H2S, N-2, and O-2 molecules are adsorbed at pristine and doped sheets to investigate adsorption selectivity. The results show that Ge and Cl doping has no benefit for H2S detection. In contrast, phosphorus increases charge transfer upon adsorption of H2S by 354% compared to pristine MoS2. Concurrently, the adsorption energy of H2S at P-MoS2 is relatively low, and it is shown in ab initio molecular dynamics that, the doping does not hinder the adsorption-site recovery. Still, the adsorption energy of H2S is significantly higher than in the case of O-2 and N-2 thus, the molecules are predicted to not impede the H2S adsorption at the doping site. Hence, the investigation predicts an enhanced response to H2S facilitated via P doping.