A series of Sr-Zr-Ti (SZT) mixed oxide catalysts were prepared by a fractional-precipitation method. These photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and ultraviolet visible (UV-Vis) diffuse reflectance absorption spectra. Photocatalytic degradation of methylene blue was investigated to determine the photoactivity of the catalyst. It was shown that with a Zr/Ti ratio<1, the SZT mixed oxide catalysts showed improved photocatalytic activity. This was attributed to lattice defects creating active photocatalytic sites because of Zr4+ doping. For Zr/Ti ratios≥1, the catalysts showed markedly improved photocatalytic activity because of new crystal ine phases of SrZrO3 and TinO2n-1 (n=4, 9) that facilitated splitting and conduction for electron/hole. Typical SZT samples (Zr/Ti=4) showed the highest photocatalytic activity, with first-order reaction rate constant 13.5 times that of a SrTiO3 sample.% 通过分步沉积法制备了不同Zr/Ti摩尔比的锶锆钛(SZT)复合氧化物催化剂,以X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、紫外-可见(UV-Vis)漫反射光谱等表征手段考察不同Zr/Ti摩尔比下SZT催化剂的结构形态,以可见光下光催化降解亚甲基蓝为模型反应考察样品的光催化活性.结果表明： Zr/Ti 摩尔比<1时SZT 催化剂发生 Zr4+与 Ti4+同质替换,引起晶格缺陷,光催化活性小幅提高； Zr/Ti摩尔比≥1时SZT 催化剂产生SrZrO3/TinO2n-1(n=4,9)的新晶相, TinO2n-1(n=4,9)的存在有利于光生电子-空穴的传导与分离,可大幅提高催化剂光催化活性.其中, SZT-5/5表现出最高的光催化活性,其一级反应速率常数达到0.2133 min-1,是同等光照条件下纯SrTiO3样品(0.0158 min-1)的13.5倍.
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