Ultrahigh Sensitivity and Excellent Selectivity of Al₂O₃-doped ZnO Micro-flowers to Acetone

Abstract

Pore spaced pure ZnO and Al2O3-doped ZnO(Al2O3-ZnO) micro-flowers were successfully synthesized by hydrothermal method. The microstructure, morphology and components were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS), respectively. Gas sensors were made to investigate the gas sensing properties. The results reveal that the sensor based on Al2O3-ZnO shows a high sensitivity to acetone. The sensitivity is 82.8 to 100×10-6 acetone gas at 260℃, which is about 4.6 times larger than that of pure ZnO (18.0) at similar conditions. The response time and recovery time are about 3s and 8s, respectively. Al2O3-ZnO also shows an excellent selectivity. Its sensitivity to acetone is 3.16 times higher than that to ethanol, which has the highest sensitivity among interfering gases under the same conditions. Thus, Al2O3-ZnO sensors can successfully distinguish acetone and ethanol with similar properties. In addition, the lowest detection to acetone is about 0.25×10-6 with theresponse is about 3.1.

Keywords

• hydrothermal method
• acetone
• Al₂O₃-ZnO micro-flower
• gas sensor