Enhanced ammonia sensing performances of Pd-sensitized flowerlike ZnO nanostructure

We report the synthesis of flowerlike ZnO nanostructure using a facile hydrothermal process, and the investigation on the ammonia (NH(3))-sensing properties of the pure and palladium (Pd)-sensitized flowerlike ZnO nanostructure. The phase purity, morphology, and structure of the pure and Pd-sensitized ZnO nanostructure are investigated. The characterized results reveal that the flowerlike ZnO has a wurtzite structure and is composed of numerous aggregated single-crystalline ZnO nanorods with a diameter of about 60 nm. Having fabricated gas sensors based on the pure and Pd-sensitized flowerlike ZnO. we find that the Pd-sensitized sensor exhibits a response of 45.7-50 ppm NH(3) at 210 degrees C, which is about 8 times higher than that of pure ZnO at the optimal operating temperature of 350 degrees C. The enhanced NH(3)-sensing performance demonstrates that the significant decrease in optimal operating temperature and the distinct increase in response are attributed to the sensitization effect of Pd. (C) 2011 Elsevier B.V. All rights reserved.