Sr掺杂LaFeO_3纳米晶光催化活性的研究

Study on Photocatalytic Activity of Sr doped LaFeO_3 Nanocrystal

采用柠檬酸络合法制备了La1-xSrFeO3（x=0，0．1，0．3，0．5）的纳米粒子催化剂，采用TG／DTA、XRD、SPM以及比表面仪等技术表征了这些纳米晶的物化性质及微观结构，并研究了其对亚甲基蓝紫外光照射降解的光催化活性。结果表明：所得催化剂均为立方相，原子Sr替代钙钛矿A位La进入晶格中形成有限固溶体；采用Chekcell软件计算精修晶胞参数后，晶胞参数随Sr掺杂量增大而变大，制得催化剂比表面积为90-95m^2／g；Sr最佳掺杂量为x=0．5，这时所形成的La0.5Sr0．5FeO3光催化剂经3h光照射后光降解率可达91．88％，比LaFeO3作为光催化剂提高了约27％。掺杂Sr后引起的晶格缺陷和结构缺陷（氧空位）浓度的增加是掺杂Sr后的LaFeO3具有高效光催化活性的主要原因。

Nanophotocatalyst La1-x SrxFeO3 （ x = 0,0. 1,0. 3,0. 5 ） were prepared by citric acid eomplexometry. To obtain physieo-ehemieal properties and mierostrueture, these powders were characterized by TG/DTA, XRD, SPM. The photoeatalytie activities of these powders in the methylene blue were studied. The results show that these catalyst are cubic and Sr substitutes for La to form limited solid solution. Cell parameter is larger with Sr doping amount increasing after refining parameter by use of Chekcell software. The specific surface area of photoeatalyst is among the range of 90-95m^2/g . Sr optimal doping amount is 0. 5, and the methylene blue photodegradation rate irradiated for 3h reaches 91.88% when La0.5Sr0.5FeO3 serves as the photoeatalyst, which exceeds 27% when the LaFeO3 as the catalyst. The improvement of photoeatalytie activity could be mainly attributed to the increasing of the lattice defect and structure defect, i, e, the oxyen vacancy concentration resulted from the Sr doping.