Abstract: Nanosized ZnO with a special three-dimensional (3D) structure was prepared by a solvothermal method using carbamide as the precipitant and then an ZnO-based ethanol gas sensitive material was obtained successfully by changing the doping amount of Ag. The phase structure and microstructure of the obtained products were characterized by XRD and SEM and the gas sensing property was tested using the static volumetric method. The results show that the gas sensing performance of 3D ZnO-based ethanol can improve effectively by doping Ag， in comparison with pure 3D-ZnO. When the amount of doping Ag is 1.5% and the volume fraction of ethanol is 0.1%， the value of gas sensor is up to 31.61， the operating temperature decreases from 350℃ to 200℃ and the response/recovery time are shorted to 10s/10s. Meanwhile， the selectivity to ethanol gas is enhanced.

Key words: ZnO, ethanol gas sensitive material, doping, three-dimensional structure, solvothermal method