La-doped SrTiO3 catalysts with different La contents were prepared by a sol-gel method,and characterized by X-ray photoelectron spectroscopy (XPS),X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),UV-Vis diffuse reflectance spectra (UV-Vis DRS),and low temperature nitrogen adsorption.The photocatalytic activities were evaluated by photo-degradation of methyl orange (MO).The results show that La-doped SrTiO3 keeps a perovskite structure and the absorption edge of 0.5％ La-SrTiO3 sample is obviously red-shifted.There is no big difference between pure SrTiO3 and 0.5％ La-SrTiO3 samples in particle size and morphologies.With the increase of La content,the photocatalytic activities of La-SrTiO3 samples under UV and visible light irradiation first increase,reaching a maximums around La content of 0.5％,and then decrease with further increasing La.Compared with pure SrTiO3,the 0.5％ La-SrTiO3 sample obviously exhibits much higher UV and visible light photocatalytic activity.The enhanced photocatalytic activity can be mainly attributed to the increase of BET surface area,the enhancement in adsorption performance,the stronger absorption in 250～650 nm light region and the lower band-gap energy level.%采用溶胶-凝胶方法制备了不同La含量掺杂SrTiO3催化剂,通过X射线光电子能谱(xPs)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外-可见漫反射光谱(UV-Vis DRS)和BET比表面积测量对其进行了表征,用甲基橙(MO)催化降解实验评价了其光催化活性.结果表明:钛酸锶经镧掺杂后仍然保持了钙钛矿结构;与纯SrTiO3相比,0.5％ La-SrTiO3样品的粒子大小和形貌没有大的区别,但它的吸收带边发生明显红移;La-SrTiO3样品的紫外和可见光催化活性随La含量增加先增加,当La含量为0.5％时分别达到最大值,然后随La含量的进一步增加而减小;与纯SrTiO3相比,0.5％ La-SrTiO3样品明显具有更高的紫外和可见光催化活性,这改善的光催化活性主要归因于比表面积增加、吸附性能提高、在250～650 nm区域有较强的光吸收和较低的禁带能级.
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