Defects-Enriched NiO Nanosheets-Based Sensor for the Detection of H₂S in SF₆ Decomposition Product Near Room Temperature under Nitrogen

Detecting the content of SF 6 decomposition products is an effective way to check the gas insulated switchgear (GIS) operation status of electrical insulation equipment. Among various detection methods, semiconductor gas sensors have the advantages of online monitoring, low cost, and high sensitivity. However, they also face some problems such as high working temperatures and poor selectivity. Herein, NiO nanosheets were prepared using a facile two-step method and subsequent annealing treatment, and exhibited high response to H 2 S gas with low concentrations under nitrogen without the involvement of oxygen and almost no response to SF 6 gas with high concentrations at near room temperature, indicating excellent gas selectivity. Among them, NiO (N600) nanosheets obtained by annealing the precursor in air at 600 °C showed the best gas sensing performance (101.0 for 11 ppm of H 2 S). Excluding the factor of oxygen, the excellent gas sensing performance of N600 is probably attributed to its higher nickel vacancy concentration, larger pore size, and larger specific surface area which can provide more active sites and capture the sulfur atoms in H 2 S. Therefore, this work confirms that the use of NiO nanosheets-based gas sensors for detecting SF 6 decomposition products to check the insulation performance of GIS is feasible.