Preparation And Properties Of TiO₂ Photocatalytic Composite Films

In this paper,the Ti/Cu coating was prepared on the surface of zirconia spherical matrix by Mechanical Milling Method,and the Cu2O/TiO2 composite photocatalytic film was prepared by subsequent oxidation sintering process.Cu/TiO₂,Al/TiO₂,Sn/TiO₂,Zn/TiO₂ and Ti/TiO2 composite photocatalytic films were prepared on the surface of zirconia spherical matrix by 2-step Mechanical Milling Method.Optical microscope,scanning electron microscope and X-ray diffraction were used to analyze the microstructure and crystal form of the films,the photocatalytic activity was evaluated by measuring the degradation rate of methyl orange solution under UV irradiation.The results showed:The Cu/Ti coating was prepared by mechanical ball milling.The effect of the ball-to-batch ratio on the film thickness was significantly higher than that of the ball milling time.When the ball-to-batch ratio was relatively large,the ball milling strength per unit time was high,the powder particle deformation rate was high,and the film formation rate was fast.The milling time has a significant effect on the service life of the film.Long-term milling can lead to an increase in the internal dislocation density and internal stress of the coating,resulting in a decrease in the service life of the film.When the milling speed is 300r/min,the milling time is 15h,and the ball-to-batch ratio is 2.5:1,the coating is continuous and dense,and the thickness reaches the maximum.The photocatalytic film prepared by carbon-coated sintered Ti/Cu coating is an efficient and novel sintering process.The Ti/Cu coating was oxidized and sintered at 500°C in carbon atmosphere.After incubation for 15h,the Cu2O/TiO2 photocatalytic film was successfully prepared,and its photocatalytic performance was better than that of CuO/TiO2 photocatalytic film that prepared under ordinary atmospheric sintering environment.The degradation rate of methyl orange solution reached 66.01%after 24 hours under ultraviolet light.The two-step mechanical ball milling method opens up new ideas for the preparation of poorly plastic or even non-metallic coatings that difficult to form on the surface of ceramic materials under normal temperature and normal pressure conditions.A layer of plastic coating with good plasticity was prepared first on the surface of the ceramic substrate,and then a two-layer composite film was successfully prepared by means of secondary ball milling.The two-layer composite film was prepared by two-step mechanical ball milling.The two-layer composite film was prepared by two-step mechanical ball milling.The material of transition layer and the milling time of the second step milling had significant effects on the photocatalytic performance of the composite film.The transition layers of Cu,Al,Sn and Zn will significantly weaken the photocatalytic activity of the composite film.The matel layer of Ti is an ideal transition layer.The Ti/TiO2 composite film has an excellent photocatalytic property under ultraviolet light conditions.After 24 hours,the degradation rate of methylene blue and methyl orange solution reached 76%.With the prolongation of the second milling time,the photocatalytic performance of Ti/TiO2 composite film decreased gradually,caused to the decrease of TiO₂ content on the surface of the second film.The photocatalytic performance of Ti/TiO₂ composite film is better than Cu₂O/TiO₂composite film,but its service life is inferior to Cu2O/TiO2 composite film.In the practical application,the comprehensive effects of factors such as photocatalytic performance,reuse time and mass loss rate of the composite film should be considered.