Preparation of Porous Flower-Like ZnO Hierarchical Nanostructures and Their Gas-Sensing Properties

The porous flower-like ZnO hierarchical nanostructures were fabricated by the method of precipitation, combining with an annealing process. The porous flower-like ZnO hierarchical nanostructures was composed of micrometer spheres which assembled by nanoflakes and the microstructure of obtained ZnO powders were characterized by X-ray diffraction, scanning electron microscope, nitrogen adsorption-desorption experiment. The sensor based on the porous flower-like ZnO hierarchical nanostructures showed high response to 100 ppm ethanol, 100 ppm acetone and 100 ppm benzene at the operation temperature of 400 degrees C, 420 degrees C and 420 degrees C, respectively. The highest response to ethanol, acetone and benzene with the concentration range of 10-1000 ppm were estimated to be 322, 220, 10, respectively. The good sensing performance of the hierarchical porous ZnO sensor indicated that the hierarchically assembled porous ZnO could be a promising candidate for highly sensitive gas sensor.