Prepartion And Photocatalytic Properties Of TiO₂-basd Nanocomposite Films

TiO2 thin films have great application prospects in the field of photocatalysis.But it limited the application of TiO2 film because the larger band gaps,higher electron-hole pair recombination rates,and smaller specific surface area.Based on above reasons,it is particularly important about modifying TiO2 thin films.In this paper,micro-arc oxidation technology were used to increase the surface roughness of pure titanium.Ag/TiO2:N nanofilms and ZnS/TiO2 nanofilms were prepared on Rough Substrate by Magnetron Sputtering.We prepared TiO2 film by magnetron sputtering technology on the rough substrate,adjusting the N flow to optimize the photocatalytic activity of TiO2 film,the photocatalytic performance of Ag/TiO2:N nanofilm prepared by Ag nanoparticle embedded was studied.By controlling the ZnS power and TiO2 thickness,the photo-carrier recombination rate of the ZnS/TiO2 nanocomposite thin film can be controlled and then the photocatalytic activity can be improved.These results were showed as follows:(1)The appropriate amount of N-doped broadened the photo-absorption range of TiO2,improved the carrier concentration,and further improved the catalytic activity of TiO2 based thin films.When the flow rate of N was 6sccm(Ar was 20sccm),the photocatalytic activity of TiO2:N film was the highest 1.36 times that of pure TiO2 film;The surface plasmon resonance effect(SPR)of Ag nanoparticles further enhanced the photocatalytic activity of Ag/TiO2:N nanofilms.The surface plasmon resonance effect(SPR)produced by Ag nanoparticles make the Ag/TiO2:N nanofilm exhibit strong resonance absorption in the 500-700 nm band.As the Ag deposition time increased,the SPR peak intensity increased and peak position broadens.It showed a significant redshift.When Ag deposition time was 40s,the SPR effect of Ag nanoparticles was the most significant,and the photocatalytic activity is the highest 1.51 times that of TiO2 film.(2)The photocatalytic activity of ZnS/TiO2 nano-films increased first and then decreases with the increase of ZnS power.When the ZnS power is 35W,the photocatalytic activity of ZnS/TiO2 composite film is the highest,which was 1.30 times that of pure TiO2 film.ZnS diffraction peak shifted leftward and the Photoluminescence intensity of ZnS/TiO2 nanocomposite film decreased and then increased with ZnS powers decreased.It showed a certain degree of lattice defects was favorable for the separation of photoelectron-hole pairs and the improvement of photocatalytic performance.Absorption edge occured redshift of ZnS/TiO2 nanocomposite films with different TiO2 Thicknesses.Photoluminescence intensity decreases first and then increases;ZnS/TiO2 nanocomposite films occured red shift with different TiO2 thickness.The photoluminescence intensity decreases first and then increases.When the TiO2 film deposition time was 90 minuts,the composite film had the minimum intensity.It showing that the probability of carrier recombination was the least at this point and the photocatalytic activity is the best.By comparing the results of the two different modification methods of TiO2 in this paper,the Ag/TiO2:N nanocomposite film structure prepared with embedded Ag particles has higher photocatalytic efficiency.