Boosting the adsorption and sensing performance of MoS2 for SF6 decomposition gases by non-metal atom doping:a DFT study

Abstract

In electrical power systems, SF₆ in Gas Insulated Switchgear (GIS) decomposes under partial discharge, yielding toxic products such as H₂S, SO₂, SOF₂, SO₂F₂. Molybdenum disulfide (MoS₂), a promising two-dimensional material, exhibits potential in gas sensing but its pristine form suffers from weak adsorption capacity for gas molecules. Herein, we carry out a systematic exploration of the gas-sensing capabilities of eight non-metal (NM)-doped MoS₂ (NM@MoS₂) materials toward SF₆ decomposition gases by leveraging first-principles calculations. The results reveal that all NM@MoS₂ substrates exhibit thermodynamic stability with negative binding energies ranging from −0.84 to −7.11 eV. Pristine MoS₂ shows weak physisorption of target gases, accompanied by low adsorption energies (−0.21 to −0.33 eV), large adsorption distances (2.90 to 3.70 Å), minimal charge transfer and limited sensitivity. In contrast, the NM@MoS₂ substrates demonstrate distinct adsorption behaviors: O@MoS₂, Se@MoS₂, and Te@MoS₂ retain physical adsorption (adsorption energies: −0.14 to −0.37 eV; distances: 2.73 to 4.02 Å), whereas B@MoS₂, C@MoS₂, N@MoS₂, P@MoS₂, and Si@MoS₂ demonstrate enhanced adsorption (adsorption energies: −0.39 to −1.67 eV; distances: 1.60 to 3.24 Å), accompanied by significant charge transfer and enhanced sensing-response. Of these substrates, Si@MoS₂ demonstrates moderate recovery times at ambient temperature (2.82 s) and demonstrates significant sensing-response to SF₆ decomposition components, highlighting its potential for practical gas sensing applications. This study demonstrates that non-metal doping can effectively enhance the gas-detection efficacy of MoS₂ towards SF₆ decomposition products, providing theoretical support for developing high-efficiency gas sensors.