Preparation And Photocatalytic Properties Of TiO₂ Based Photocatalytic Films

Photocatalysis technology is an effective way to solve the pollution of antibiotic wastewater.TiO₂ is a widely studied photocatalysis material,but its application is limited due to its response only in the ultraviolet region,low light quantum efficiency,difficulty in recycling TiO₂ powder,etc.Therefore,TiO₂ nanorod array films materials（TNAs films）were designed and prepared.The array structure was conducive to the transmission of electrons,and the film materials were easy to be recycled.Narrow band gap BiOI and noble metal Ag were deposited on TNAs films to make it have light response under visible light,inhibit photogenerated electron hole recombination and improve light quantum efficiency.The structure and properties of the prepared films were characterized by XRD,XPS,SEM,UV-Vis DRS,photocurrent test,Mott Schottky test,etc.the photocatalytic performance of the films was evaluated by photocatalytic degradation of oxytetracycline.TNAs films were prepared by hydrothermal method.The TNAs films were prepared under the conditions of 0.5 m L tetrabutyl titanate,150℃hydrothermal temperature and 8 h hydrothermal time.The TNAs films were rutile phase TiO₂ with a diameter of about 150 nm.The TiO₂ nanorods grew perpendicular to the substrate and tended to be consistent.The nanorods were evenly spaced and arranged in an array.The degradation rate of oxytetracycline was 31%when exposed to xenon lamp for 3 hours.BiOI/TiO₂ nanorod array films（BiOI/TNAs films）were prepared by successive ionic layer adsorption and reaction.Tetragonal BiOI was deposited on rutile TiO₂ nanorod arrays,which broadened the light response range of TNAs films,narrowed the band gap,made the photocatalytic films had visible light response,inhibited the recombination of photogenerated electrons and holes,and improved the optical quantum efficiency.BiOI/TNAs film deposited by BiOI for 6 times and illuminated by xenon lamp for 3 hours had a photocatalytic degradation rate of 61%for oxytetracycline,which was twice that of TNAs film.Ag/BiOI/TiO₂ nanorod array films（Ag/BiOI/TNAs films）were prepared by depositing Ag on BiOI/TNAs films by photochemical deposition.After depositing Ag,the optical response performance and photocurrent density of the photocatalytic films were further improved,which was conducive to the transmission of photogenerated carriers.Ag/BiOI/TNAs film deposited twice by Ag and illuminated by xenon lamp for 3 hours had a photocatalytic degradation rate of 80%for oxytetracycline,which was 1.3 times that of BiOI/TNAs film and 2.6 times that of TNAs film.