Preparation, characterization and sensing properties of zno nanotubes

Hexagonal ZnO nanotubes have been synthesized by a simple sonochemical treatment andthe subsequent etching process at relative low temperature without any catalysts or templates. The sample has been characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscope (TEM) and selected area electrondiffraction (SAED). The nanotubes are appeared as single crystal with average diameter of180 nm, lengths of 1.5 urn and inner pore size of 90 nm. Gas sensors fabricated from the as-prepared ZnO nanotubes were tested to different concentration of toxic gases. A comparison in sensing performance between ZnO nanorods and ZnO nanotubes was investigated. It was found that ZnO nanotubes sensors possess higher sensitivity to toxic gases than ZnOnanorods sensors. The higher sensing properties of ZnO nanotubes sensors are attributed to the higher active surface area of the tubular structure.