Preparation Of Titanium Dioxide Composite Material For Efficient Photocatalysis

The problem of water pollution is more and more serious, which becomes a big challenge for the human life. Compared with the traditional treating methods, photocatalysis has developed quickly in the recent 20 years and exhibits obvious advantages such as efficient and complete degradation of pollutants. Therefore, it is expected to become one of the most effective methods to control environmental pollution in the 21st century. TiO2 has been proved to be the promising photocatalyst for widespread environmental applications due to its optoelectric properties, nontoxicity, cost effectiveness, and long-term stability against chemical corrosion and photocorrosion. However, it can only absorb ultraviolet light due to its wide band gap (3.2 eV), and is not responsive to visible light (λ> 400 nm) that accounts for around 46% of the total solar energy. Therefore, exploring visible light efficient photocatalysis has been an urgent issue from the viewpoint of solar energy utilization. In this work, F-TiO2 was synthesized by sol-gel method, Ag2O/TiO2 by coprecipitation method, and Ag2O/F-TiO2 using Ag2O and F-TiO2 by co-precipitation method. By F doping and composite introducing visible light absorption is increased and photoelectron-hole pair recombination in TiO2 is reduced Thereore the photocatalytic performance is improved. The main contents are as follows:1. F-TiO2 was synthesized through the hydrolysis of tetrabutyl titanate in NH4F solution by sol-gel method, and its photocatalytic performance under visible light irradiation was investigated. The results show that:(1) F-TiO2 exhibits a better photocatalytic performance than pure TiO2; (2) the photocatalytic performance of F-TiO2 is dependent on the F doping concentration in TiO2 and the F-TiO2 achieves a highest photocatalytic degradation rate of 91% in the degradation of Methylene blue(MB) at 4h; (3) the enhanced photocatalytic performance is ascribed to the increase of visible light absorption and the reduction of photoelectron-hole pair recombination in TiO2 with the F doping.2. Ag2O/TiO2 was synthesized by coprecipitation method, and its photocatalytic performance under visible light irradiation was investigated. The results show that:(1) Ag2O/TiO2 composites exhibit an enhanced photocatalytic activity than TiO2; (2) the photocatalytic activity of Ag2O/TiO2 composites is dependent on the proportion of Ag2O in the composites and the composites achieves a highest MB degradation rate of 96% at 3h; (3) the enhanced photocatalytic activity is mainly ascribed to the increase in light adsorption and the reduction in photoelectron-hole pair recombination with the introduction of Ag2O.3. Ag2O/F-TiO2 was synthesized by coprecipitation method, and its photocatalytic performance under visible light irradiation was investigated. The results show that:(1) Ag2O/F-TiO2 composites exhibit an enhanced photocatalytic activity than F-TiO2; (2) the photocatalytic activity of Ag2O/F-TiO2 composites is dependent on the proportion of Ag2O in the composites and the composites achieves a highest MB degradation rate of 93% at 1h; (3) the enhanced photocatalytic activity is mainly ascribed to the increase in light adsorption and the reduction in photoelectron-hole pair recombination with the introduction of Ag2O.