Room-Temperature Detection of SF₆ Decomposition Byproducts Using a g-C₃N₄@SnO₂–ZnO Composite Sensor

Sulfur hexafluoride (SF6) is usually used as an insulating medium in gas-insulated switchgear to prevent arc formation in electrical transmission and generation systems. Decomposition of SF6 can occur due to various electrical faults, and detection of its decomposition products is widely utilized for fault monitoring. Notably, sulfuryl fluoride (SO2F2), a significant decomposition component of SF6, is challenging to detect at room temperature. This study presents the synthesis of a heterojunction comprising zinc oxide (ZnO) microrods and tin oxide nanoparticles (SnO2 NPs) through a hydrothermal method, followed by the integration of graphitic-carbon nitrate (g-C3N4) to enhance sensitivity toward SO2F2 at room temperature. Incorporating g-C3N4, known for its extended carrier lifetime, excellent charge carrier mobility, and metal-free catalysis properties, significantly elevated the gas sensing capability. Enhancement of the heterojunction with g-C3N4 led to a notable increase in responsivity to 5.6 (2.8) for 80 (10) ppm concentrations, marking an improvement of over 200% at low concentrations. This investigation underscores the efficacy of the g-C3N4@SnO2–ZnO composite in the detection of SF6 decomposition products like the hazardous SO2F2 at room temperature, offering a potent tool for fault diagnosis within gas-insulated switchgear-based high-voltage electrical safety systems.