Layered structure of NiCo-LDH/SnO2 heterostructure for high-performance H2S gas sensors

Gas-insulated switchgear (GIS) is widely applied in modern power systems because of its excellent insulation and arc-quenching properties. However, under abnormal conditions such as partial discharge or overheating, SF 6 may decompose to produce hazardous gases including H 2 S, which threaten both equipment reliability and maintenance safety. Therefore, the development of highly sensitive and reliable H 2 S sensors is of great importance for the monitoring of SF 6 decomposition products. In this work, NiCo-LDH/SnO 2 composite nanomaterials are synthesized via a hydrothermal-calcination method by uniformly loading SnO 2 nanocrystals onto layered NiCo-LDH nanosheets. The influence of different NiCo-LDH/SnO 2 mass ratios on the structural characteristics and gas-sensing properties is systematically investigated. Among the prepared samples, the NiCo-LDH/SnO 2 (1:2) composite exhibits the best sensing performance, with a relatively high specific surface area of 103.8 m 2 g -1 , mesoporous structures with pore sizes mainly distributed at 5-6 nm, and an oxygen vacancy concentration of 58.05 %. The corresponding sensor shows a high response of 12.68 toward 30 ppm H 2 S at 240 °C, with response and recovery times of 56 s and 47 s, respectively. In addition, the sensor demonstrates good linearity (R 2 = 0.99799), excellent selectivity, and long-term stability. The enhanced sensing performance is mainly attributed to the synergistic effects of the p-n heterojunction, optimized mesoporous structure, relatively high specific surface area, and abundant oxygen vacancies. This work provides an effective strategy for designing high-performance H 2 S sensing materials for monitoring SF 6 decomposition gases in GIS equipment.