Study On Photocatalytic Degradation Of FeTiO₃-based Semiconductor Materials

FeTiO₃,one of the most common minerals in the earth’s crust natural resources,is a perovskite-structured semiconductor material with a rhomboidal structure（spatial group R-3）.Compared with traditional photocatalytic materials such as wide-band gap TiO₂and ZnO,FeTiO₃ has a band gap of 2.5-2.8e V,which can absorb part of visible light for photocatalytic degradation.However,FeTiO₃ prepared by the traditional solid phase method has the disadvantage of large particle size and low carrier separation efficiency in the photocatalytic reaction process,which also limits its catalytic degradation performance.Based on this,in this paper,FeTiO₃ nanoparticles with small particle size will be synthesized by sol-gel method,and the serious photogenerated carrier recombination problem will be solved by MoS₂recombination to form heterojunction structure and rare earth element doping.Finally,FeTiO₃-based materials with excellent performance will be obtained.Specific work contents are as follows:（1）FeTiO₃ nanoparticles were prepared by sol-gel method and further dispersed on MoS₂ flowers prepared by hydrothermal method to form FeTiO₃/MoS₂ heterojunction structure.Compared with pure FeTiO₃,the interfacial electric field formed by heterojunction can effectively promote the directional transfer of photogenerated electrons to the conduction band of FeTiO₃,while the directional transfer of holes to the valence band of MoS₂.Among the composites,MF10 showed the best performance,and the degradation rate of tetracycline hydrochloride（TCH）reached 84.79%.（2）Since FeTiO₃/MoS₂ heterojunction only has significant photocatalytic degradation activity on TCH,in order to further improve the catalytic activity of FeTiO₃,doping modification of FeTiO₃ with La element is carried out.The degradation ability of FeTiO₃ to three different pollutants doped with La was investigated.The results show that the introduction of La element can promote the degradation activity of FeTiO₃ to tetracycline hydrochloride（TCH）,methylene blue（MB）and erioglaucine disodium salt（BB）.The test analysis shows that this is because La doping generates new energy levels,which can broaden the visible light absorption range of FeTiO₃,and also inhibits the recombination of photogenerated carriers in FeTiO₃,thus improving the separation efficiency of photogenerated carriers.When the doping amount of La is 12 mol%,the degradation rates of TCH,MB and BB are 91.37%,77.39%and 85.66%,respectively（3）Considering that Ce doped photocatalyst can introduce Ce³⁺/Ce⁴⁺REDOX pairs to enhance the photocatalytic activity,Ce doped FeTiO₃ was studied.The results show that Ce³⁺/Ce⁴⁺exists in FeTiO₃ at the same time,which brings more oxygen vacancies,so it can rapidly capture photogenerated electrons to promote the separation of electron-hole pairs and adsorb reactive oxygen species.When the doping amount of Ce is 10 mol%,the degradation rates of TCH,MB and BB are 97.5%,95.4%and 84.6%,respectively.Cyclic experiments show that 10 mol%Ce/FeTiO₃ has excellent stability.It is a kind of photocatalyst that can degrade various pollutants and be reused...