关键词: 乙醚, 催化发光, 纳米Co₃O₄, 气体传感器, 低温

Based on the cataluminescence (CTL) reaction of ethyl ether on nano-Co₃O₄, we developed a direct gas sensor for monitoring ethyl ether in air. According to the high CTL intensity and well selectivity of ethyl ether on chain-ball nano-Co₃O₄ at low temperature, a stable and high sensitive gas sensor for ethyl ether was constructed. In our work, we synthesized the nano-Co₃O₄ material, which was characterized by XRD and SEM. For the fabrication of the sensor, Co₃O₄ nanomaterial was directly coated on the heating ceramic chip to form a layer of catalysts with a thickness of 0.1 mm. Then, the Co₃O₄ coated heating ceramic chip was inserted into a quartz tube with an inner-diameter of 12 mm, and the temperature of Co₃O₄ layer was controlled by the digital heater. When gas samples passed through the Co₃O₄ material in the quartz tube by the air flow, the CTL was generated during the catalytic oxidation on the surface of Co₃O₄. The CTL signals were recorded by BPCL Ultra Weak Chemiluminescence Analyzer, and the data was processed by Origin 6.0. The optimized conditions were as follows: the heated temperature was at 176 ℃, the wavelength was 440 nm, and the air flow rate was 180 mL/min. The linear range of CTL intensity versus concentration of ethyl ether vapor was 4.0～1500 ppm (R＝0.9993) with a detection limit of 1.67 ppm (3σ). In addition, the response time was less than 2 s, and recoveries of artificial samples by this method were 97.3%～103.0%. Furthermore, another eleven volatile organic compounds including ammonia, benzene, formaldehyde, trichloromethane, acetonitrile, acetaldehyde, acetic acid, ethanol, acetone, tetrachloromethane and ethyl acetate were detected by this sensor, which indicated the little disturbance by ethanol, acetone, tetrachloromethane and ethyl acetate (＜0.8%), while no remarkable signals were observed for the other seven compounds. After a continuous analysis of more than 140 h, the CTL signals remained stable, which demonstrated the longevity and steady performance of this sensor. At last, the products were analyzed to demonstrate the possible mechanism of the CTL oxidation of ethyl ether on the surface of Co₃O₄.

Key words: ethyl ether, cataluminescence, nanosized Co₃O₄, gas sensor, low temperature