Mourão Henrique A J L, Ribeiro Caue
Universidade Federal de São Carlos (UFSCar), Departamento de Química - Rod. Washington Luiz, km 235 - CEP: 13565-905, São Carlos, SP, Brazil.
J Nanosci Nanotechnol. 2011 Sep;11(9):7876-83. doi: 10.1166/jnn.2011.4712.
A number of reports have been published on use of TiO2 in thin films, magnetic nanocomposites, or heterostructures such as TiO2/Ag and TiO2/SnO2, as catalysts for water decontamination. Hence, semiconductor materials such as SnO2, associated with TiO2 in such nanocomposites, should be assessed in depth for such applications, especially those involving complex structures, such as magnetic photocatalytic nanocomposites. The present study describes the synthesis, characterization and testing of the photocatalytic potential of TiO2 or SnO2 magnetic nanocomposites obtained by the polymeric precursor and the hydrolytic sol-gel methods. The nanocomposites TiO2/CoFe2O4 and SnO2/CoFe2O4 were synthesized from polymeric precursors while TiO2/Fe3O4 and SnO2/Fe3O4 were synthesized by the hydrolytic sol-gel method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (FEG/SEM) and transmission electron microscopy (TEM). The photocatalytic potentials were evaluated by rhodamine B dye photodegradation under UV-C radiation. Compared to SnO2, the nanocomposites with a coating of TiO2 were found to show better photocatalytic activity, but the SnO2 magnetic nanocomposites showed some photocatalytic activity, even though SnO2 is reported to be inactive for these purposes. As for the synthesis method, the nanocomposites obtained from polymeric precursors had smaller surface areas, but higher photocatalytic activity, than those obtained by the hydrolytic sol-gel method. This observation was attributed to the higher crystallinity and a more active surface resulting from calcination of the polymeric precursor material.
已经发表了许多关于二氧化钛在薄膜、磁性纳米复合材料或异质结构（如TiO₂/Ag和TiO₂/SnO₂）中作为水净化催化剂的应用报告。因此，在这类纳米复合材料中与二氧化钛相关的半导体材料（如SnO₂），应针对此类应用进行深入评估，尤其是那些涉及复杂结构的应用，如磁性光催化纳米复合材料。本研究描述了通过聚合物前驱体法和水解溶胶 - 凝胶法制备的TiO₂或SnO₂磁性纳米复合材料的合成、表征及光催化潜力测试。纳米复合材料TiO₂/CoFe₂O₄和SnO₂/CoFe₂O₄由聚合物前驱体制备，而TiO₂/Fe₃O₄和SnO₂/Fe₃O₄通过水解溶胶 - 凝胶法制备。通过X射线衍射（XRD）、扫描电子显微镜（FEG/SEM）和透射电子显微镜（TEM）对材料进行表征。通过在UV - C辐射下罗丹明B染料的光降解来评估光催化潜力。与SnO₂相比，发现涂覆有TiO₂的纳米复合材料表现出更好的光催化活性，但SnO₂磁性纳米复合材料也表现出一定的光催化活性，尽管据报道SnO₂在此类用途中无活性。至于合成方法，由聚合物前驱体制备的纳米复合材料比通过水解溶胶 - 凝胶法制备的纳米复合材料具有更小的表面积，但光催化活性更高。这一观察结果归因于聚合物前驱体材料煅烧后具有更高的结晶度和更活跃的表面。
