Enhanced toluene sensing characteristics of TiO2-doped flowerlike ZnO nanostructures

The large-scale flowerlike ZnO nanostructures, consisting of many aggregative nanorods with the diameter of about 60 nm, were prepared by a simple and facile hydrothermal route. The toluene sensing properties of the pure ZnO and TiO2-doped ZnO nanostructures were tested at different operating temperatures from 160 to 390 °C and toluene concentrations ranging from 1 to 3000 ppm. The results indicate that the response of the ZnO nanostructures towards toluene was enhanced significantly by TiO2 doping, which was deposited onto the ZnO products by evaporation. It is found that the TiO2-doped ZnO sensor exhibits remarkably enhanced response of 17.1 at the optimal operating temperature of 290 °C to 100 ppm toluene, which has been improved up from 7.4 at 390 °C from pure ZnO nanostructures.