Preparation Of Visible-light Response TiO₂ And Modification Of Composition With Activited Carbon Fiber

TiCl₄ was used as raw materials,nanosize TiO₂ was prepared by acid catalyzed hydrolysis method;N-F co-doped TiO₂ photocatalysts(TONF) were prepared from aqueous solution of TiCl₄ and NH4F;finally,the TiO₂/ACF composite were prepared by leaching ACF in TiO₂ precursor solution.DRS,XRD,SEM,XPS and N₂(77 K) adsorption isotherm were used for materials characterization The details were follows:The optimal preparation condition for the high active TiO₂ was determined as follows: HCl as catalysts,hydrolysis reaction temperature 98℃and calcinations temperature 500℃. The prepared TiO₂ prcursor was uncrystalline.With the calcination temperature increased, uncrystalline was transformed into anatase at 400℃,accompanying with the S_BET decreased and particle size increased.Anatase phase TiO₂ completely transformed can be realized at 800℃.The threshold of TiO₂ has moved towards length waves.N-F codoped TiO₂ photocatalyst(TONF) were prepared by acid catalyzed hydrolysis method from the aqueous solution of TiCl₄ and NH₄F.The activity of the TONF was investigated through degradation of phenol under artificial visible light and ultraviolet light. The results showed that N-F co-doped TiO₂ exhibited significant improvement of visible light activity.N-F co-doping could improve dispersion of TiO₂,inhibit particle size agglomeration and retard phase transformation.Doped N can extend the light response of TiO₂ to visible light region.Inaddition,narrower band gap formed by F-doping was beneficial to the high visible light photocatalytic activity.TiO₂/ACF composite was prepared by loading TiO₂ precursor on activated carbon fiber by dip-coating method.High concentration gaseous toluene was used as model compound for photocatalytic activity test.TiO₂/ACF showed high activity under UV lamp irradiation.For the used condition in this work,the optimal size of ACF is 2×7.5 cm.The sample with optimal size dip-coating for 2 times exhibited the highest activity for toluene removal,and the toluene was degradated 70%within 60 min.With the increasing of dip-coating times,specific surface area of TiO₂/ACF decreased.Also,the activity of TiO₂/ACF changed regularly.A synergy effect between TiO₂ and ACF was observed for the prepared TiO₂/ACF used in toluene removal.