TiO₂-Doped HfSe₂ Monolayer for Efficient SF₆ Decomposition Gas Detection

Monitoring sulfur hexafluoride (SF ₆ ) is vital in the electrical insulation sector, where it serves as a key insulator. SF ₆ decomposition, caused by operational wear or aging, releases hazardous gases such as SO ₂ , SOF ₂ , SO ₂ F ₂ , and H ₂ S, raising safety concerns. However, the effectiveness of current nanoscale gas sensors is compromised by SF ₆ ’s protective nature, struggling with multi-gas detection. This study utilizes density functional theory (DFT) calculations to assess the performance of a novel 2D TiO ₂ -doped HfSe ₂ (TiO ₂ -HfSe ₂ ) monolayer. We found that TiO ₂ doping not only broadens the bandgap and enhances the structural stability ( E _b = -2.934 eV) of the HfSe ₂ monolayer but also increases its gas adsorption ability (197.142-573.104%). The sensors can effectively distinguish SF ₆ gas and its by-products in the sequence: SO ₂ F ₂ > SOF ₂ > SO ₂ > H ₂ S >> SF ₆ . The sensor effectively spots SF ₆ gas at 298 K, ensuring smooth gas-insulated system operations. Further analysis indicates that solvents with higher dielectric constants significantly boost adsorption strength (16.907-71.996%), improving gas differentiation. Finally, a literature comparison confirms the exceptional performance of the TiO ₂ -HfSe ₂ monolayer, endorsing its application as a reliable sensor for SF ₆ decomposition gases.