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

Sulfur hexafluoride (SF 6 ) is usually used as an insulating medium in gas-insulated switchgear to prevent arc formation in electrical transmission and generation systems. Decomposition of SF 6 can occur due to various electrical faults, and detection of its decomposition products is widely utilized for fault monitoring. Notably, sulfuryl fluoride (SO 2 F 2 ), a significant decomposition component of SF 6, is challenging to detect at room temperature. This study presents the synthesis of a heterojunction comprising zinc oxide (ZnO) microrods and tin oxide nanoparticles (SnO 2 NPs) through a hydrothermal method, followed by the integration of graphitic-carbon nitrate (g-C 3 N 4 ) to enhance sensitivity toward SO 2 F 2 at room temperature. Incorporating g-C 3 N 4, 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-C 3 N 4 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-C 3 N 4 @SnO 2 –ZnO composite in the detection of SF 6 decomposition products like the hazardous SO 2 F 2 at room temperature, offering a potent tool for fault diagnosis within gas-insulated switchgear-based high-voltage electrical safety systems.