NiO nanoparticle-decorated SnO2 nanosheets for ethanol sensing with enhanced moisture resistance

In a high relative humidity (RH) environment, it is challenging for ethanol sensors to maintain a high response and excellent selectivity. Herein, tetragonal rutile SnO₂ nanosheets decorated with NiO nanoparticles were synthesized by a two-step hydrothermal process. The NiO-decorated SnO₂ nanosheet-based sensors displayed a significantly improved sensitivity and excellent selectivity to ethanol gas. For example, the 3 mol% NiO-decorated SnO₂ (SnO₂-3Ni) sensor reached its highest response (153 at 100 ppm) at an operating temperature of 260 ºC. Moreover, the SnO₂-3Ni sensor had substantially improved moisture resistance. The excellent properties of the sensors can be attributed to the uniform dispersion of the NiO nanoparticles on the surface of the SnO₂ nanosheets and the formation of NiO-SnO₂ p-n heterojunctions. Considering the long-term stability and reproducibility of these sensors, our study suggests that the NiO nanoparticle-decorated SnO₂ nanosheets are a promising material for highly efficient detection of ethanol.