Preparation And Performance Research Of The Anatase TiO₂ Hollow Nanospheres And The Fe-doped Samples

The world economy develops rapidly when it comes to the 21 st century, nevertheless, situation of environment becomes worse as the pollution and damage to the nature are more than ever. Many countries endeavour to solve the pollution problems. As a promising semiconductor, TiO₂ hold the advantages of high photocatalytic capability, stable chemical property and nontoxicity. However, there are still many defects in TiO₂ photocatalysis because of the absorption wavelength belongs to the ultraviolet mostly. Through the former study can we know that the hollow sphere particles behave better in receiving the radiation. Anatase crystal is a favorable form for photocatalysis in the many crystal forms of TiO₂. Concluded that,in this paper,we have prepared the nanoscale anatase hollow spheres and tested the photocatalytic capability under simulated sunlight. In the further research, we doped the Fe-ion into the TiO₂ matrix and tested the influence to the photocatalysis of different doping concentration. Our method is as follows:1. The Ti?SO₄?₂ and NaOH were added into the beaker with the coprecipitation method. The anatase Ti O₂ hollow nanospheres were fabricated with the as-followed hydrothermal and calcination. In the next steps, the Fe?NO3?3 was added into the original reaction solution to synthesize the Fe-doped anatase TiO₂ hollow spheres. The anatase TiO₂ samples were synthesized under different reaction conditions, then we analyzed and characterized the samples through the XRD, TEM, SEM and BET analysis. Through a series of experiments, we concluded that holding the temperature at 130 ? for 48 hours is the best hydrothermal reaction parameter. In the calcination, the best parameter was proved to be 450 ? for 3 hours. In this way, we can get the anatase TiO₂ hollow sphere structure with good crystallinity.2. The photocatalytic capability was tested after the analysis and characterization, We set a Xe lamp as the reaction photosource and the methyl orange solution as the reagent. The photocatalytic reaction test lasts for 100 minutes. During the reaction, the solution absorbance was tested every 20 minutes. The results showed that under different reaction conditions, the samples behaved different photocatalytic capability. Samples prepared through the 130 ? hydrothermal reaction have the better photocatalytic efficiency than those under other temperatures. A 48-hour-hydrothermal reaction time is proved to be advantageous to prepare samples with good photocatalytic capability. In the conclusion, we choose the hydrothermal reaction parameters as 130 ? for 48 hours as the optimum choice, which ensures a better crystallinity and structure that lead to best photocatalysis performance.3. In this part, we prepared Fe-doped TiO₂ and compared its performance with that of pure anatase TiO₂. The Fe-doped TiO₂ was synthesized through Fe ion doping in the coprecipitation reaction. It was successfully synthesized which can be tested through the EDS and XRD analysis. The photocatalytic experiments showed that the doping of Fe-ion can improve the photocatalytic efficiency in certain concentration. The degradation of the pure TiO₂ is 28%, and the degradation of the 1% Fe-doped TiO₂ is 43%?It proved the metal doping can improve the photocatalytic capability of TiO₂. Experiments also discovered that degradation decreases with the over-doping of the Fe-ion because superabundant Fe-ion will destroy the premier crystal structure and lower the application value. In conclusion, certain concentration Fe-doped TiO₂ can improve the photocatalytic capability of the pure TiO₂.