Research Of Plasma Photocatalytic Sensor Based Ag/AgCl Nanocomposite

It is an important subject to deal effectively with organic wastewater treatment to improve the pollution of water enviro nment. Photocatalyst could degradate organic pollutants by utilizing visible light, with the advantages of low energy consumption, no secondary pollution and so on. In addition, the detection of organic pollutants in water is an important part of water enviro nment monitoring and water quality analysis. The existing detection methods need to consume large amounts of heavy metal salt, acid/alkali and other toxic and harmful substance, causing the secondary pollution. In this paper, on the basis of the photocatalytic oxidation system, we developed a photocatalytic thin film sensor based on silver/silver chloride, which could catalysis the degradation of organic pollutants in the water and monitor the concentration online by using silver nanoparticle plasmonic resonance at the same time. Loading fullerenes on the silver/silver chloride sensing film, further improved the sensitivity of the sensor.Firstly, the silver/silver chloride composite photocatalyst was prepared by the simple coprecipitation method and then UV light illu mination within 10 min. Silver/silver chloride composite photocatalyst were characterized by UV-Vis spectra, XRD, SEM, proving that the size of silver chloride cubes was about 300-500 nm, while the silver nanoparticles loading on the surface of silver chloride was about 10-50 nm. The content of silver chloride was far greater than the silver nanoparticles and the combination of silver chloride and silver nanoparticles have no impact on their crystal structure. The degradation rate of malachite green reached 80% in 60 min, the system of silver/silver chloride dispersion showed highly catalytic activity and stability.Then, the silver/silver chloride dispersed droplets coated on the glass substrate, after drying and annealing at 300 oC, silver/silver chloride sensing film was achieved. Hydrophilic treated fullerene dispersion was spin coated on the silver/silver chloride film, also annealing at 300 oC. After spin coating and annealing process, fullerene loaded on the surface of silver/silver chloride film, through UV-Vis spectra, SEM characterization. The blue shift of the SPR absorption peak was 19 nm. The photocatalytic degradation rate of malachite green was about 91% by fullerene/silver/silver chloride film, which was higher than the 51% of silver/silver chloride film.Finally, based on visible light catalytic oxidation system, we constructed a plasmonic photocatalytic sensor, using the rock frequency of the silver nanoparticles SPR absorption peak to online monitor the organic molecules in the water. Then we studied the difference between the silver/silver chloride and fullerene/silver/silver chloride film in photocatalytic sensing. RI sensitivity experiment resulted that as the silver/silver chloride film of 794 nm/ RIU, fullerene/silver/silver chloride film was 688.31 nm/ RIU, after the loading of fullerenes, RI sensitivity of silver/silver chloride film was reduced about 105.69 nm. Sensing the different concentrations of malachite green in water, fullerene/silver/silver chloride film had higher sensitivity and lower background signals. The sensor has a great potential in detection of the oxidation of organic pollutants in water with many advantages, such as low energy consumption, no secondary pollution and so on.