Study On VOCs-sensors Based On Cataluminescence

Volatile organic compounds(VOCs) affect everywhere in our common life. Gas sensor, as a major tool for the gas detection, has unparalleled advantages on detecting VOCs. Cataluminescence gas sensor is a new kind of sensor with various interesting features. Comparing with traditional sensors, cataluminescence gas sensor does not need external light source and complicated circuits, meanwhile it prevents the scattering of light. Therefore it presents a high sensitivity, high selecitivity and a wide linear range that superior to photoluminescence sensors. With such good features, it attracts great research interests. In this paper, the nano-catalyst is used as sensitive materials, and four cataluminescence sensors are designed and investigated. By the work of this paper, the usage of the cataluminescence sensors are significantly expanded. The main contents of this paper are as follows:1. The CTL system of PO – nanosized Ce O2 has been found and investigated. Accordingly, we proposed a new method to detect PO based on cataluminescence, and possible corresponded chemical luminescence mechanism is discussed. The studies on CTL mechanism reveal the relation between the catalytic emission intensity and the catalyst reaction product. Under the optimum conditions, with the catalytic emission intensity and concentration of propylene oxide staying at 10-150 ppm, the sensor showed a good linear relationship, short response time, a correlation coefficient of r = 0.9974, and a detection limit of 0.9 ppm. Continuously working within 100 h, CTL response of the sensor showed good stability, and less than 1.2 % of the relative standard deviation. The system can provide a new means of detect PO in the future.2. The cataluminescence characteristics of Ether on the surface of the copper oxide in different morphology were investigated. An ether sensor based on nanometer copper oxide cataluminescence is constructed. Different morphology and structure of the copper oxide nanometer catalytic materials have different catalytic activity, which causes different cataluminescence properties. Empirical results show that the morphology has a certain impact on sensor, and the flake copper oxide has higher catalytic efficiency than granular copper oxide. Choose the former for the sensor has a lower detection limit, and a high sensitivity and good selectivity.3. The cataluminescence system of the triethylamine- nanometer Ag2 Mo O4 was studied. The interference situation of 11 common kinds of the same concentration of volatile organic compounds(carbon tetrachloride, ammonia, acetic acid, aniline, ethanol, benzene, butylamine, chloroform, acetone, diethylamine and formaldehyde) were examined. Experimental results show that except ammonia, chloroform, acetone and diethylamine showed slight interference(about 5%), the rest of the seven kinds of material do not produce obvious CTL signal. Throwing triethylamine gas over 140 h, luminous intensity of the sensor has no significant decrease, demonstrating that the sensor has a good selective and a stable performance. The sensor has a good application prospect in terms of triethylamine monitoring.4. The cataluminescence of the 4- methyl- 2- pentanone on the surface of the Pt/Ba O/Al2O3 was studied. Accordingly a new detection method based on the principle of 4- methyl- 2- pentanone cataluminescence. By a more detailed research on 4-methyl- 2- pentanone- nanocomposite Pt/Ba O/Al2O3 system, we discovered that the method has low detection limit of 0.5 ppm. With the same concentration of gas throwing to the nanocomposite Pt/Ba O/Al2O3, except acetone, carbon tetrachloride, carbon trichloride, acetic acid, formaldehyde and ether have slight interference, the other gases have no response.