Reliable Detection of SF ₆ Breakdown Byproducts Using 2D Non-Hexagonal Carbon Allotrope Nanosheets

Sulfur hexafluoride (SF6), widely used as an insulating gas in the power industry, decomposes during long-term operation into byproducts such as H2S, SO2, SO2F2, and SOF2. Reliable detection of these compounds is essential, since their type and concentration provide diagnostic signatures of faults in gas-insulated switchgear. We employ density functional theory combined with nonequilibrium Green’s function calculations to evaluate pristine two-dimensional carbon allotropes with nonhexagonal rings, namely Graphene+, T-graphene, and Biphenylene, as potential field-effect nanosensors. To characterize the surfaces’ atomic structures, we simulated scanning tunneling microscopy images for filled states. Each surface exhibits a distinct brightness pattern that allows its identification. All interactions occur via physisorption, enabling rapid recovery and device reusability. Graphene+ uniquely identifies SO2 and SOF2 at a single gate voltage, while T-graphene and Biphenylene selectively detect H2S and SO2. These findings demonstrate that nonhexagonal carbon nanosheets combine high sensitivity, fast recovery, and intrinsic selectivity, underscoring their potential for real-time monitoring of SF6 degradation products in power systems.