Preparation Of Rare Earth Metal/TiO₂ And MoS₂/TiO₂ Composites And Their Photocatalytic Properties

TiO₂ has the advantages of stable chemical properties,non-toxic side effects and low energy consumption,especially high photocatalytic activity.Therefore,it has attracted more and more attention in the field of photocatalysis.Due to the wide band gap（3.2 e V）of TiO₂,the spectral absorption range of TiO₂ is very narrow.It only shows certain photocatalytic activity under ultraviolet light,while sunlight contains only 5%ultraviolet light.Therefore,the photocatalytic performance of TiO₂ under visible light is poor.In the process of photocatalysis,the high recombination rate of photogenerated electron hole pairs is a main reason to limit the photocatalytic performance of TiO₂ under visible light.TiO₂ Doped and coated composites can effectively reduce the recombination rate of photogenerated electron hole pairs.In this paper,rare earth metal ions doped TiO₂ and Mo S₂/TiO₂ composites were used to modify TiO₂ in order to improve its photocatalytic performance.The morphology,structure and element composition of the experimental samples were characterized by XRD,SEM,XPS and UV Vis.The photocatalytic performance was characterized by the degradation rate of Rhodamine B（RHB）solution.The main contents are as follows:1.The La-doped TiO₂ photocatalytic materials were synthesized by sol-gel method,hydrothermal method and template method,respectively.The morphology,elemental composition and photocatalytic properties of the materials were studied.The results show that the La-doped TiO₂ photocatalyst prepared by sol-gel method has the best photocatalytic performance.When the doped amount of La is 0.5%,its degradation rate to rhodamine B（RHB）solution with a concentration of 10 mg/L is 61.28%,which is 46.75%higher than that of TiO₂undoped La.2.Because the samples prepared by sol-gel method can not form spherical morphology,the rare earth metal Er doped TiO₂ photocatalysts were synthesized by hydrothermal method and template method respectively in this chapter.The morphology,structure,element composition and photocatalytic performance of the materials were studied.The results show that the Er doped TiO₂photocatalytic material prepared by hydrothermal method has the best photocatalytic performance.When the Er doped amount is 0.75%,the degradation rate of Rhodamine B（RHB）solution with the concentration of 5mg/L is 64.32%,which is 12.75%higher than that of TiO₂ without Er doping.Compared with La doped TiO₂ photocatalytic materials prepared by hydrothermal method,the performance improvement is also less.The performance of Er doped TiO₂ Prepared by template method is better than that of La doped TiO₂.3.Because of the morphology of TiO₂ Prepared by template method is relatively uniform,but the photocatalytic performance is improved less.Therefore,the Mo S₂/TiO₂ composite photocatalytic material is synthesized by hydrothermal method for TiO₂ synthesized by template method,and the influence of different p H value of precursor solution on the sample is explored in the experimental process.The morphology,structure,element composition and photocatalytic properties of the materials were studied.The results show that the photocatalytic performance of Mo S₂/TiO₂ composite photocatalyst prepared by hydrothermal method is better.When the Mo/Ti ratio is 2:1 and the p H of the precursor solution is 3,the photocatalytic performance of the sample is the best.The degradation concentration of Rhodamine B（RHB）solution with a concentration of 20 mg/L can reach 80.01%after 135min illumination.Through the summary of the above three parts,it is concluded that the photocatalytic performance of Mo S₂/TiO₂ composite photocatalytic materials is greatly improved compared with the rare earth metal elements La and Er doped TiO₂,and the morphology and performance of the samples when the p H of the reaction precursor solution is 3 are better than those prepared when the p H value is not adjusted.