A DFT study of SF6 decomposition products (H2S, SO2, and CS2) adsorption and detection on Pd-ZnO/SnS2 ternary composites

Real-time and accurate detection of SF₆ decomposition products is a crucial approach to diagnosing internal faults of gas-insulated switchgear (GIS). However, the limited sensitivity and selectivity of SnS₂ gas sensors have hindered their further development and application. This study employs density functional theory to design the optimal Pd-ZnO/SnS₂ monolayer structure and investigate its adsorption behavior toward H₂S, SO₂, and CS₂. The findings indicate that Pd atom doping and ZnO nanoparticle incorporation significantly enhance the conductivity of the SnS₂ monolayer, reducing the band gap to 0.54 eV and lowering the work function by 5.019 eV. Regarding gas adsorption and sensing, the Pd-ZnO/SnS₂ monolayer outperforms intrinsic SnS₂ and ZnO/SnS₂, showing the order in which SF₆ decomposition products are selected is: CS₂ > SO₂ > H₂S. Additionally, the sensitivity and recovery time of Pd-ZnO/SnS₂ as a gas sensor were evaluated, confirming its excellent sensing performance for SO₂ and CS₂ detection. This study provides theoretical insights to advance the application of gas sensors in online insulation equipment monitoring.