NO2 sensing characteristics of ZnO nanorods prepared by hydrothermal method

ZnO nanorods were prepared via a hydrothermal reaction in a solution containing Zn(NO3)2⋅6H2O, NaOH, cyclohexylamine, ethanol and water, and their NO2 and CO sensing behaviors were investigated. The morphology and agglomeration of ZnO nanorods could be manipulated by controlling the amount of water in the solution, which was explained by the variation in the [OH−] due to an interaction between the water and cyclohexylamine. Sea-urchin-like and well-dispersed ZnO nanorods were prepared at low and high water content, respectively. Well-dispersed ZnO nanorods showed 1.8 fold change in resistance at 1 ppm NO2 while there was no significant change in resistance at 50 ppm CO. The present ZnO nanorods can be used in automated car ventilation systems to detect NO2 in the presence of CO.