Preparation Of Semiconductor Photocatalytic Films And Study On Self-cleaning Properties

Semiconductor photocatalytic films have been widely studied due to their high photocatalytic activity and good hydrophilic lipophilic amphiphilicity.In this paper,nano-TiO2 film and TiO2/SiO2 layered film were prepared by Sol-gel method using self-made liquid flow device.Polyethylene glycol(PEG)and triblock copolymer(P123)were used as templates.Mesoporous layered TiO2/SiO2 film and mesoporous composite TiO₂-SiO₂ film were prepared.X-ray diffractometry(XRD),scanning electron microscopy(SEM),UV-Vis spectrophotometer,contact angle measuring instrument,standard grid method for the crystal form,surface morphology,optical properties,wettability and adhesion of the sample Characterize.The photocatalytic activity of different sample films was studied by using methyl orange solution as a degradant.The hydrophilicity of several film samples was determined by contact angle measurement.The results show that the hydrophilicity and photocatalytic activity of SiO2 doped film are higher than that of pure TiO2,and the mesoporous structure can effectively improve the utilization of light energy,enhance the photocatalytic activity,and promote the adsorption of water molecules on the surface of the film.The film is hydrophilic.At the same time,the introduction of SiO₂ can enhance the adhesion between the film and the substrate,so that the film has good mechanical stability and improves the service life of the film.The main reason is that the single TiO₂ film has high reflectivity.The introduction of SiO₂ can effectively reduce the reflectivity of the film and improve the utilization of light energy.At the same time,SiO₂ can strengthen the van der Waals force between the film and the substrate,improve its adhesion and enhance the adhesion.Anti-acid and alkali ability,enhance the service life.The formation of mesoporous structure can improve the transmittance of light,improve the separation of electron-hole pairs in TiO₂ film,improve photocatalytic activity,and facilitate the formation of surface hydroxyl groups,improve hydrophilicity,and have pore-like mesopores.Conducive to the physical adsorption of the film,enhance its hydrophilicity.Among all the prepared film samples,the composite mesoporous TiO₂-SiO₂ film has high photocatalytic activity,can achieve super-hydrophilicity under short-term illumination,and maintain a super-hydrophilic state for a long time after no light.By the combination of SiO₂ and TiO₂,the reflectivity of the film system is lowered,the utilization rate of light energy is increased,the surface hydroxyl group is increased,the photocatalytic activity and hydrophilicity are improved,the adhesion between the film and the substrate is improved,and the mechanical stability of the film is enhanced..The results show that when the volume of SiO₂ is about 20%of the composite film,the film has the best photocatalytic,hydrophilic and adhesion properties,and has good self-cleaning and anti-fog properties.