Gas-sensing property improvement of ZnO by hierarchical flower-like architectures

New morphologies often play a critical role in governing properties of nano-materials. Here, using hydrothermal method and reagents of sodium citrate and polyethylene glycol (PEG), we synthesize the ZnO nano-crystals and find that they exhibit hierarchical flower-like architectures assembled by nanosheets. Further comparative studies demonstrate that the sodium citrate assists a uniform growth of the nanosheets, and the PEG provides nucleation sites for the assembling of the nanosheets, both of which play a critical role in producing such unique flower-like architectures. Consequently, this sample is found to show excellent sensing performances to the target ethanol owing to its largest amount of petals, intervals, and pores. Such an unexpected morphology holds substantial promise for rendering ZnO as a potential gas-sensing material for a broad range of future sensor applications.

► The ZnO nanocrystals show flower-like architectures assembled by nanosheets.
► Sodium citrate and PEG are important for producing flower-like architectures.
► Gas sensing properties are enhanced significantly due to the unique structures.
► Such morphology makes ZnO promising for a wide range of future sensor applications.