NiS hierarchical nano-microspheres for high-sensitive ethanol gas sensing

Development of highly sensitive ethanol gas sensors is critical for numerous applications including industrial gas leak monitoring, environmental air quality assessment, food fermentation process control, and automotive drunk driving prevention. Here, NiS hierarchical nano-microspheres (NiS-HNMs) were successfully synthesized via a facile hydrothermal method. The gas sensing performance toward ethanol was comprehensively evaluated by testing key parameters. The results demonstrate that the NiS-HNMs exhibit remarkable efficiency in ethanol detection. The gas sensor fabricated with NiS-HNMs achieves a response value of 4.33 toward 10 ppm ethanol at 130°C. Meanwhile, the gas sensor demonstrates excellent selectivity, short-term repeatability, and long-term stability for ethanol detection, along with an excellent linear relationship over the concentration range of 1–10 ppm. The superior gas sensing performance of the NiS-HNMs is attributed to their hierarchical nano-microsphere structure, with a large specific surface area (174.09 m 2 /g), providing abundant active sites. Additionally, a large amount of surface-adsorbed oxygen was detected on the surface of NiS-HNMs, which indicates that more adsorbed oxygen molecules participate in ethanol gas sensing reactions, thus contributing to their excellent gas sensing performance. In summary, this study successfully synthesized hierarchically structured NiS nano-microspheres, which provide a novel perspective for constructing high-performance ethanol sensors and show significant application potential in high-sensitivity detection fields.