| Cataluminescence(CTL) gas sensor has an extremely important role in environmental monitoring, public safety, human health and other fields. Since It has advantages of no need of light source, no material loss, low cost, high sensitivity, fast analysis, easy compact and easy to operate. However, the CTL gas sensor suffers from the fact that poor selectivity, high temperature and other shortcomings still restricting the application of the currently commercially available semiconductor gas sensor in practice. This dissertation has designed four bismuth-based semiconductor materials’ cataluminescence gas sensor after we selected from different composition and morphology of the bismuth-based semiconductor material, which has set a new direction for the development and application of the gas sensor. The main contents of this paper are as follows:1、The study found that under the low working temperature, we developed a direct gas sensor for monitoring trace of propionaldehyde in air based on the strong cataluminescence reaction of propionaldehyde on Bismuth vanadate and the possible mechanism was investigated. The linear range of CTL intensity versus concentration of propionaldehyde vapor was 70-1660 mg/m3(R= 0.9965), with a detection limit of 19 mg/m3(S/N = 3), which the optimized conditions were as follows: the wavelength was 620 nm, the heated temperature was at 202 ℃, and the air flow rate was 380 m L/min. In addition, another fourteen volatile organic compounds were detected by this sensor and after a continuous determination of propionaldehyde for more than 90 h, the CTL signals remained stable, which showed that the sensor was good selectivity, longevity and steady performance.The sensor was applied to determine propionaldehyde in artificial samples which the recoveries were from 97.5% to 103.0%.2、A new cataluminescence gas sensor based on nanomaterials’ catalytic activity and adsorption properties was developed for determination of carbon tetrachloride. The nanosized flower-like Bi2S3 has been choosed as the sensitive material, which was known for its non-toxic, environmental protection and catalytic activity. And we also investigated the response from flow rate, wavelength and temperature on the catalytic. Studies have shown that CTL intensity versus concentration of carbon tetrachloride from 0.9-165.0 mg/L has a good response linearity, and the limit of detection was 0.3 mg / L. Furthermore, both of the sensor’s sensitivity and selectivity were good, the working temperature was only 186 ℃.3、A new method for determination cyclopentanone with Bi2WO6 sensor materials of cataluminescence gas sensor was reported. Under optimum conditions, except acetone, ethanol and propanal produced a weak response, other ten kinds of interfering gases in the system had no luminous phenomenon which indicated that the system’s selectivity was excellent, interfering gases were include acetone, cyclohexane, formaldehyde, methanol, ethanol, ethyl acetate, acetonitrile, propanal, toluene and benzene. At the same time, methanol, ethanol and acetonitrile were selected as the three common organic solvents in cyclopentanone related industries to explore the feasibility of the system, the results show that recovery of 97.4-99.2%. It has provided a new method for the industry of cyclopentanone.4、According to previous work, the material of Bi2WO6 nanoflowers were prepared by a simple hydrothermal method, there was almost no response when cyclopentanone across from the material’s surface, but when the ethanol across from the material, the response was strongly. A new cataluminescence gas sensor for ethanol monitoring was designed based on the sensitive material of Bi2WO6 nanoflowers. Under optimal conditions, CTL intensity versus concentration of ethanol from 0.7-126.5 mg/m3 has a good response linearity, and the limit of detection was 0.2 mg/m3. Because of high sensitivity, good selectivity and durability of the sensor, it will contribute to monitoring of ethanol in industry, life and medical field. |
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