Study On Preparation Of N, F-codoped TiO₂ Nanoparticles And Their Photocatalytic Activity

In previous studies, TiO₂ was the most commonly used catalyst because of its non-toxicity, reasonable cost, high availability, photochemical stability and relatively high photocatalytic activity. Its application scope is very extensive, such as sewage treatment, air purification, solar energy utilization, antibacteria, preventing mist and clean function etc. Photocatalysis is a promising method that has great potential for conversion of photon energy into chemical energy and decomposition of pollutants in air and water including dye, surfactants, pesticide and all kinds of difficult biodegradation of toxic organic pollutants, degradation products are CO₂ and H₂O and harmless ions.TiO₂ with a band gap of 3.2 eV can be photoexcited under irradiation of UV light (λ<387.5 nm), TiO₂ particles with UV light produces holes and electrons. Most hydroxyl radicals are generated upon the oxidation of OH? or H₂O by these photogenerated holes. Such holes are principally responsible for the destruction of organic species. But UV light is only about 2-4% of sunlight. Therefore, considerable effort has been made to increase the absorption of TiO₂ in the visible region to improve its visible light response through various surface modifications such as doping of various metal or nonmetal oxides.This study evaluates the photodegradation efficiency of bisphenol A (BPA) and acid red B in a visible light/doped TiO₂ system. Doped TiO₂ was generated by the sol–gel method. N,F-TiO₂ was prepared by three different methods, denoted as N,F-TiO₂(1), N,F-TiO₂(2), N,F-TiO₂(3), respectively. Their photocatalytic activities were compared through selects of experiments. The effect of irradiation time, dose of catalysts, light power and solution acidity on degradation of acid red B was investigated by UV-vis specra. The results showed that N,F-TiO₂(1) has hightest photocatalytic activity for degradation of 10 mg·L^-1 acid red B, when irradiation time is 4.0 h, degradation rate is up to 100%. Ce,N,F-codoped TiO₂ was prepared by sol-gel. The effect of irradiation time, dose of catalysts, light power and solution acidity on degradation of BPA was investigated by UV-vis specra. The results showed that degradation rate of 10 mg·L^-1 BPA is up to 100%, when irradiation time is 8.0 h. Fe,N, F-codoped TiO₂ was prepared by sol-gel. The effect of irradiation time, dose of catalysts, light power and solution acidity on degradation of BPA was investigated by UV-vis specra. The results showed that degradation rate of 10 mg·L^-1 BPA is up to 100%, when irradiation time is 4.0 h.