Synthesis, Modification And Photocatalytic Properties Of New Layered Perovskites Ln₂ Ti₂O₇ By Template Method

New layered perovskite type A₂B₂O₇ oxides were an inorganic non-metal material which has many functions of physics and chemical, it's an important photocatalysts with extensive application prospect in the treatment of waste dye water. The source reagents were lanthanum nitrate and butyl acrylate titanate (TBOT), template material of polyethylene glycol (PEG) and complexing agent of diethanolamine (DEA); new layered perovskite type A₂B₂O₇ oxides were synthesized by template method combined with vacuum drying technology and characterized by TG-DTA, TEM and XRD. Using the 15W UV light as the source, the photocatalytic activity of Ln₂Ti₂O₇ (Ln=La,Ce,Pr,Nd) powder was tested by photocatalysis degrading methyl orange (MO) solution.1) On the basis of every influencing factors, novel layered perovskites type (Ln=La,Ce,Pr,Nd) were prepared by template method combined with vacuum drying technology firstly. XRD results indicated that all of the materials have perfect perovskite structure; TEM results indicated that the photocatalysts ; TG-DSC results indicated that the optimum thermal treating temperature is 800℃for 4h.2) Photocatalytic degradation of MO was first investigated on Ln₂Ti₂O₇ photocatalyst under 15 W UV light. The results show that: pH=2.0, the amount of Ln₂Ti₂O₇ is 0.1g, the degradation rate of Ln₂Ti₂O₇ is up to 95%; the order of photocatalytic activity is as follows: Ln₂Ti₂O₇ (La2Ti₂O₇;The results of orthogonal experiment indicated that: pH=2.0, the solution temperature is 60℃, the amount of Ln₂Ti₂O₇ is 0.7g, the degradation rate of the La₂Ti₂O₇ and Pr2Ti2O7 powders doped with 3% Fe³⁺ is 100% only after 4-6h.4) Systematically study on the influential factors, the optimal conditions of MO degradation are as following: the PEG molecular weight is 400, the thermal treating temperature is 800℃, the amount of the catalyst is 0.3g; the initial concentration of MO is 10mg/L, pH=2.0, the solution temperature is 60℃; 5) The photocatalytic activity of La₂Ti₂O₇ increased obviously dope with K+ and Fe³⁺, the optimal doping content of Fe³⁺ is 3%; the photocatalytic degradation of MO is significantly improved by the addition of a small amount of H2O2.