Preparation And Application Of TiO₂-based Photocatalyst Under Visible Light Irradiation

Titanium dioxide?TiO₂?has been considered as one of the most promising materials for its application in photocatalysis because of its high chemical stability,non-toxicity and high photocatalytic activity.However,traditional TiO₂photocatalyst can only absorb UV light owing to its wide band gap.Furthermore,the photocatalytic performance of photocatalyst is also limited by the ability of separation of photogenerated carriers.Therefore,it is meaningful to develop an effective route to enhance visible responsive activity and improve the photogenerated electron-hole pairs separation efficiency of photocatalysts.In this paper,we attempted to improve the photocatalytic performance of TiO₂ by doping metal element and formation of heterostructures.The catalyst obtained were characterized by XRD?SEM?UV-Vis DRS?PL.Their photocatalytic activities were investigated by photodegradation of rhodamine B.On the other hand,the photocatalytic degradation properties of the modified photocatalysts on different supports were investigated which aimed to solve the utilization and recovery of TiO₂powder.1.Fe doped TiO₂ photocatalysts were synthesized by sol-gel method.The as-prepared Fe/TiO₂ photocatalysts showed high photocatalytic performance when the mass ratio of Fe and TiO₂ reached 0.1%and the calcination temperature was400?,and the degradation rate of rhodamine B was 87.6%under visible light radiation.The Fe doping greatly affect on photocatalytic performance because of the narrow band gap and defect of crystalline structure.2.g-C₃N₄/TiO₂ heterojunction photocatalysts were synthesized by sol-gel method.The as-prepared g-C₃N₄/TiO₂ photocatalysts showed high photocatalytic performance when the mass ratio of g-C₃N₄ and TiO₂ reached 50%and the calcination temperature was 400?under visible light radiation.UV-Vis absorption spectrum and photoluminescent spectra confirmed that suppression of the recombination of photogenerated carriers were beneficial to improve the photocatalytic activity.3.Fe/TiO₂ and g-C₃N₄/TiO₂ composite photocatalyst coatings were prepared on different supports?alumina ceramic,alumina ball,carbon fiber mesh?by spraying method.The composite photocatalyst coating on the carbon fiber mesh had the best degradation effect.The stability test showed that the composite photocatalyst coating had a certain adhesion and catalytic activity on the surface of the support.