Preparation And Photocatalytic Properties Of SnO₂ Based Nanocomposites

With the continuous development of industry,all kinds of pollutants have increased sharply,and the emission of organic pollutants has become one of the main sources of environmental pollutants.Low cost and efficient degradation of organic pollutants has become the focus of researchers.Photocatalysis technology is one of the best means to deal with water pollution.SnO₂is cheap,non-toxic,stable and acid and alkali resistant.It is a wide band gap n-type semiconductor material（E_g=3.6 e V）.Its conduction band potential（CB）and valence band potential（VB）are 0 e V and 3.6 e V respectively,and has a high exciton binding energy of 130 me V.Metal oxide/organic polymer nanocomposites can show special mechanical,thermal,optical,rheological,magnetic and electrical properties.The composite material can obtain good synergistic effect,and the combination of metal oxide and conjugated polymer can effectively improve the catalytic performance of photocatalyst.On this basis,the following work is carried out in this paper:（1）SnO₂/C nanocomposites with high dispersion were prepared by solvothermal method with tin tetrachloride pentahydrate（Sn Cl₄·5H₂O）as tin source and absolute ethanol as solvent.The SnO₂/C nanocomposites prepared by this method have the characteristics of high dispersion,small particle size and large specific surface area.（2）SnO₂/C/PANI composites modified by polyaniline（PANI）were prepared by in-situ polymerization with SnO₂/C nanocomposites as matrix.Photocatalysis experiments show that SnO₂/C/PANI composites have excellent performance in the degradation of Rhodamine B（Rh B）.The degradation rate can reach more than 95%after 30 min of illumination and almost completely degraded after 50 min.The effects of different surfactants on the photocatalytic degradation of Rh B of SnO₂/C/PANI composites and the effects of aniline concentration on the properties of SnO₂/C/PANI composites were investigated.The structure and morphology of SnO₂/C/PANI composite materials were characterized and analyzed,and the kinetic characteristics and photocatalytic mechanism of its degradation of Rh B were studied.（3）SnO₂/C/PPy composites were prepared by in-situ polymerization of SnO₂/C nanocomposites and polypyrrole（PPy）.The photocatalytic experiment showed that SnO₂/C/PPy composite had excellent degradation performance for Rh B,and the degradation rate could reach more than 95%after 20 min of illumination,while it had been almost completely degraded at 50 min.The preparation and properties of SnO₂/C/PPy composites prepared under different conditions were investigated.The structure and morphology of SnO₂/C/PPy composite materials were characterized and analyzed.The results showed that SnO₂/C/PPy composite had a 99.1 m²/g Large specific surface area.The kinetic characteristics and photocatalytic mechanism of Rh B degradation were studied.