Ultrasensitive and low detection limit of acetone gas sensor based on W-doped NiO hierarchical nanostructure

The pristine and W-doped NiO hierarchical flower-like hollow spheres were prepared by a one-step hydrothermal reaction without template and used to fabricate the gas sensors. Their gas sensing performances and possible sensitive mechanism were investigated. The results indicated that the strategy of doping W into NiO could effectively improve the gas sensing properties. The sensor based on the 4.0 at% W-doped NiO exhibited the optimal gas sensing performance, giving a ppb-level detection limit and an ultra-high response of 198.1 to 100 ppm acetone at 250 °C, which was about 139 times higher than that of the pristine NiO. The significantly enhanced sensing properties to acetone could be attributed to the changes in crystallite size, specific surface area, and hole carrier concentration caused by W doping.