Study On Visible-light Photocatalytic Performance Of Composite Films Prepared From Polyvinyl Chloride And SnO₂ Nanoparticles

SnO₂ nanoparticles were synthesized with a microwave-assisred hydrothermal method using SnCl₄·5H₂O as precursor.A suspension containg SnO₂ nanoparticles and PVC solution were prepared.Conjugated polymer/SnO₂ composite membranes were successfully synthesized through heat treatment of PVC/SnO₂ membranes which can get through spin coating method.The CPVC/SnO2 composite films were characterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,Fourier-transform infrared spectroscopy（FTIR）,UV-vis diffuse reflectance spectroscopy（UV-Vis DRS）,and photoluminescence spectroscopy（PL）.XRD pattern show that the crystallization of the composite film didn’t change obviously.TEM images indicate that the sphere-like nanoparticles firstly tend to aggregate and from larger particles with the size of ca.100 nm,and these particles are dispersed evenly into composite film.From the UV-visible diffuse reflectance spectra,it can be concluded that CPVC/SnO₂ composite film showed higher visible light absorption than neat SnO₂ film.The PL spectrum demonstrates that the re-combination probability of photogenerated electron/hole pairs in composite films greatly decreases,and their separation efficiency obviously increases.The photocatalytic activities of conjugated polymer/SnO₂ composite membranes were investigated by monitoring the degradation of RhB under visible light irradiation.The results showed when mass ratio of PVC and SnO₂ was 1:3,the temperature of thermal-treatment was 150℃and the time of thermal-treatment was 2h,the photocatalytic abllity of CPVC/SnO2 composites was the best.The results reveal that the CPVC/SnO2composite films possess excellent visible-light photocatalytic activity and stability,and the visible-light photocatalytic activity is about about 28 times of that of neat SnO₂ film and25 times of that of g-C3N4 if their specific surface area is considered.As the PVC content,heat-treatment temperature or time increases,the visible-light photocatalytic activity of the composite films increases first and then decreases.The visible-light photocataltic mechanism of the CPVC/SnO2 composite film has been discussed.In addation,a partly conjugated polymer can be obtained from ordinary PVC when was heated at high temperatures 150℃for 2h via dehydrochlorination reaction.The Ag/CPVC nanoparticles were prepared by a Photochemical reduction method and were characterized.The noble metal can extend the light absorption into a visible range and enhance the electron-hole separation due to Schotttky barrier formation,and then improve its photocatalysis ability.