Enhanced acetone-sensing properties to ppb detection level using Au/Pd-doped ZnO nanorod

ZnO nanorods doped by different amount of Au and Pd were successfully synthesized via one-step microwave-assisted hydrothermal method. The structure, morphology and composition of the as-synthesized products were characterized by X-ray diffraction (XRD), field-emission electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Gas sensors based on ZnO and Au/Pd-doped ZnO nanorods were fabricated and their gas sensing properties were tested for various gases. The results indicate that the incorporation of Au and Pd elements can greatly enhance the gas sensing properties of ZnO sensors. Specifically, the sensor based on 2.0 wt% Au-doped ZnO exhibits the highest response, quickest response and recovery characteristics, best selectivity, low operating temperature, as well as good long-term stability towards acetone. After incorporation of Au (2.0 wt%), the detection limit of Au-doped ZnO sensor decreases to 5 ppb and the response increases to 17 under 1 ppm acetone at 150 degrees C, which is more than triple the responses of ZnO sensor. The results demonstrate that the developed Au-doped ZnO sensor has great potential for ppb-level acetone detection in human breath for diagnosing diabetes.