Synthesis of carbon microsphere-assisted snowflake-like ZnO nanomaterials for selective detection of NO2 at room temperature

In this paper, the snowflake-like ZnO nanomaterials were prepared by combining zinc salt impregnation and high-temperature calcination with carbon microspheres as the sacrificial template. The effects of ethanol concentration in aqueous solution on the microstructure and sensing properties of ZnO nanomaterials were investigated. The results showed that using 25 % ethanol-containing aqueous solution as impregnation solution, snowflake-like ZnO nanomaterials (ZnO-25) showed excellent sensing performance for NO2 at room temperature. It is mainly attributable to the rich channels and large specific surface area of the snowflake-like ZnO, which facilitates the rapid diffusion of the target gas. A large amount of chemisorbed oxygen can promote the surface reaction. In addition, the unremoved carbon during calcination promotes the electrical properties of ZnO. This strategy will provide a new sight on developing a type of sensitive NO2 gas sensing device working at room temperature.