High-Performance Co₃O₄ Nanoparticle-Based Gas Sensor for Leakage Detection of Eco-Friendly Insulating Gas C₄F₇N

Perfluoroisobutyronitrile (C₄F₇N), an eco-friendly insulating gas, has been extensively utilized in diverse gas-insulated equipment (GIE) to replace the most potent greenhouse gas SF₆. Nonetheless, given the low toxicity of C₄F₇N, the potential leakage risk at a high-pressure operational environment cannot be overlooked, making the development of highly sensitive gas sensors for leak detection essential. Herein, Co₃O₄ was selected as a specific gas sensing material for C₄F₇N detection based on the density functional theory screening. The Co₃O₄-based gas sensor was prepared, and its response performance was systematically evaluated. The interaction mechanism between Co₃O₄ and C₄F₇N was also examined by the oxygen vacancy theory. The sensor demonstrates a low detection limit of 0.15 ppm at its optimal operating temperature of 300 °C, exhibiting exceptional selectivity and repeatability, with a stability response time of 55.5 s and recovery time of 1478 s. The sensor's application potential under actual working settings was validated using a simulated leakage test. Relevant results provide guidance for the leakage monitoring of the C₄F₇N-based GIE.