Study On Photocatalysts Of Lanthanum Titanate And Lanthanum Titanium Oxynitride

The photocatalysis technology has received wide attention from scientists.To explore a wide range of photocatalyst materials has also been ongoing,in recent years,the perovskite structure material have attracted the attention of all people for its excellent properties.The research work of this thesis is on the exploration of lanthanum titanate,and its oxynitride,the perovskite structure materials as efficient photocatalysts.The main works are as follows:?1?La₂Ti₂O₇ nanoribbons for photocatalytic removal of methyl orange from water.Lanthanum titanate?La₂Ti₂O₇?nanoribbons were synthesized by hydrothermal method using titanium dioxide nanoribbons as a template,and La₂Ti₂O₇ nanosheets were synthesized by hydrothermal method,too.The photocatalytic properties were compared by degradation of methyl orange solution.The results show that the properties of one-dimensional morphology of La₂Ti₂O₇ were better than that of structure.This result is mainly due to the smaller band gap of nanoribbons,one-dimensional structure,better dispersion and so on.In addition,in the cycle test,such La₂Ti₂O₇ nanoribbons is also stable during the photocatalytic process.?2?Three spherical LaTiO₃ on the photocatalytic removal of methyl orange from water.Three kinds of LaTiO₃ with self-assembled spherical morphology were synthesized by ethylene glycol-assisted solvothermal method and their photocatalytic properties were compared by degradation of methyl orange solution.The experimental results show that the nanostrip spheres has the best photocatalytic properties,which is mainly attributed to the smaller band gap,more suitable porosity,better use of light and less aggregation.With the addition of the capture reagent,we understand that the major active species in the catalyst are hole and superoxide radicals.On a cyclic test,the catalyst remains active after several uses.Finally,the forming process of these morphologies is analyzed,ethylene glycol plays a very important role.By adjusting the ratio of ethylene glycol to water,samples with different morphologies can be synthesized.?3?Synthesis of visible-light-driven LaTiO₂N photocatalyst with different morphologies.This part mainly studies the synthesis of different morphologies of visible light catalyst LaTiO₂N.We use the traditional two-step method,partial replacement of oxygen atoms in the precursor oxide by the nitrogen atom is accomplished by the high-temperature ammoniation reaction of lanthanum titanate.The precursors were the lanthanum titanate with different morphologies,synthesized in the previous two chapters,and the La₂Ti₂O₇ of block morphology.We confirmed that the formation of LaTiO₂N with different morphologies undergos different amination reaction conditions.