Synthesis of 1-dimensional ZnO and its sensing property for CO

One-dimensional (1D) needle-like ZnO nanorods with aspect ratio about 50 were successfully synthesized by a sodium dodecylsulphate (SDS)-assisted hydrothermal process at lower temperature (85 °C). The morphology and structure of crystals were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. Experimental results show that SDS, ratio of OH−/Zn2+ and hydrothermal reaction time play important roles in the formation and oriented growth of ZnO nanorods. Gas sensors have been fabricated using 1D ZnO powders to examine the response towards 40 ppm CO over a range of operating temperature from 150 °C to 450 °C. The highest response is 49.58 at the operating temperature of 400 °C. The response was greatly enhanced by doping Nd element as surface modifier or ZrO2 as secondary oxide. The effect of doping on the ZnO structure and gas sensing has been discussed by X-ray photoelectron spectroscopy (XPS) analysis.