Research on Film-type Methanol Sensor Based on ZnO/Polyaniline Nanocomposites

The spherical nano ZnO and polyaniline (PANI)/ZnO composites were prepared respectively by low-temperature hydrothermal method and in situ polymerization with zinc acetate, sodium hydroxide and ammonium persulfate etc. A new film-type methanol gas sensor was designed by transferring ZnO/PANI nanocomposites onto corning glass substrate with Pt. inter digital electrodes using dip. coating method. The crystalline phase and microstructure of ZnO/PANI nanocomposites were displayed by X. ray diffraction (XRD) and scanning electron microscope (SEM), and the sensitive mechanism and electrochemical characteristic of ZnO/PANI were analyzed by X-ray photoelectron spectroscopy (XPS). These characteristic tests of methanol sensor were carried out on the traits of sensitive performance, temperature, relative humidity, dynamic response, selectivity and stability in gas sensor test system. As a result, the methanol sensor based on PZ50 nanocomposites had a high response (1795. 6) and a high relatively humidity level (90%) and its dynamic response time and recover time of methanol sensor were 6. 9 and 19. 6 s respectively, when the operating temperature was 30 degrees C and the methanol gas concentration was 25 mg/m(3). This kind of sensor showed good anti. disturbance to the gases, including N2O, formaldehyde, ethanol, acetone and 1,3. butadiene. Besides, the response value of methanol sensor was only attenuated about 2. 3% after it was continually applied to the methanol detection on automobile for about 12 weeks.