Synthesis of cactus-like NiO nanostructure and their gas-sensing properties

• The porous cactus-like NiO are synthesized by a simple hydrothermal approach.
• Our sample has highly selectivity and sensitivity to 100 ppm acetone at 260 °C.
• The possible gas sensitive reaction mechanism is proposed.

Cactus-like NiO was successfully synthesized by adjusting reaction time of a simple hydrothermal approach. The different morphologies of the NiO samples obtained by different reaction time were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM). And the gas-sensing performance of these products was studied, too. The results indicated that the sensor based on the cactus-like NiO nanostructures obtained by choosing appropriate reaction time showed much better sensing properties than other samples. The response of the sensor based on cactus-like NiO was about 13.51–100 ppm acetone at a working temperature of 260 °C, and the response and recovery time was 24 and 39 s, respectively. The improvement gas sensing properties based on cactus-like NiO sensor may be due to the unique structures, the good crystallization and large surface area.