Preparation And Properties Of Titanium Dioxide And Composite Films Based On Liquid Phase Deposition Method

The advantages of TiO₂,such as non-toxic,good stability and low price,make it the first choice material in the field of photocatalysis and widely used.In fact,the response of wide band gap semiconductor with 3.2eV band gap is limited to some extent in the visible light range.Therefore,by doping,recombination,surface sensitization and other methods to suppress the combination of photogenerated electrons and holes produced by semiconductors,improve the separation efficiency of the two,so as to achieve the purpose of improving the photocatalytic performance.In addition,the experiment confirmed that the TiO₂ film prepared by the liquid phase method is easy to crack,and a large number of practices through doping metal elements,metal oxides,non-metal oxides and other methods to improve the film cracking.The main work of this paper is as follows:?1?In this paper,TiO₂ thin films were prepared by low temperature liquid phase method to improve the cracking degree of the films.TiO₂ thin films with controllable morphology and grain size were prepared by liquid deposition?LPD?.The effects of?NH₄?₂TiF₆ concentration,pH value and?NH₄?₂TiF₆:H₃BO₃ molar ratio on the grain size and morphology of the films were studied.The samples were characterized by X-ray diffraction,SEM and UV-Vis.The results show that the parameters have a significant effect on the growth and nucleation rate of the grains,thus forming TiO₂films with different morphology and grain size.The capillary stress between the film grains is related to the grain size,which leads to the film cracking.Therefore,the cracking of TiO₂ prepared from LPD can be reduced by adjusting deposition parameters.?2?The photocatalytic efficiency of the Ni?OH?₂-TiO₂ composite film was investigated by liquid deposition.The results show that the composite films with different morphology can be obtained with different composite deposition time.The uncomposite Ni?OH?₂ thin film is thin lamellar structure.With the extension of deposition time,the composite thin film gradually presents a thick layered structure.Until the deposition time is 30 minutes,the morphology of the composite thin film is that TiO₂ is all wrapped in the lamellar gap,forming a noodle like structure,and the layered structure disappears completely.The photocatalytic results show that the film with 15 minutes deposition time of TiO₂ has the highest photocatalytic performance,and the photocatalytic efficiency can reach 92%in 6 hours,and the photocatalytic efficiency of the film has almost no change after 5 cycles.The photocatalysis efficiency of the composite films in different environments such as acid and alkaline dyes was also studied.The results show that the photocatalytic efficiency of the composite film is higher than that of the single film.?3?Vanadium bronze has become a good energy storage material because of its special network structure,which can promote the photocatalytic performance.TiO₂was compounded with vanadium bronze to investigate its photocatalytic performance under UV irradiation.The results show that the composite film has more efficient catalytic performance than the single film.It is worth mentioning that the dark adsorption capacity of single vanadium bronze film is the strongest,but its photocatalytic degradation performance is lower than that of single TiO₂ film and composite film in the subsequent photocatalytic experiments.This shows that the single vanadium bronze has a strong adsorption performance,and can use its unique three-dimensional network structure in the composite film to promote the improvement of photocatalytic efficiency.