Simple route to monodispersed silica-titania core-shell photocatalysts
Simple route to monodispersed silica-titania core-shell photocatalysts
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DOI：
10.1021/la703899j
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发表时间：
2008-06-17
期刊：
影响因子：
3.9
通讯作者：
White, T. J.
中科院分区：
文献类型：
--
作者：
Lim, Suo Hon;Phonthammachai, Nopphawan;White, T. J.
采用溶胶-凝胶法合成了单分散的二氧化硅-二氧化钛核壳型光催化剂，该方法不需要pH调节、阳离子聚电解质或表面活性剂，将水解的钛酸四丁酯浸渍到二氧化硅球中，室温下保温，然后用乙醇/水（1：1）溶剂浓缩。在10%v/v二氧化钛溶胶中的四个涂覆循环产生均匀的二氧化钛壳。使用粉末X射线衍射图的Rietveld分析结合X射线荧光光谱法定量评估催化剂的质量。在煅烧过程中，锐钛矿到金红石的转变被延迟到1000摄氏度，这类似于比通常观察到的高300摄氏度。二氧化钛的热稳定性和比表面积的提高是通过缓慢的晶体生长的TiO 2。发现在400-600 ℃下煅烧的核-壳光催化剂的光催化活性与二氧化钛的厚度成正比，但与表面积没有直接关系。
A monodispersed silica-titania core-shell photocatalyst was synthesized via a sol-gel route without the need of pH adjustment, cationic polyelectrolytes, or Surfactants in a process where silica spheres were impregnated with hydrolyzed titanium tetrabutoxide, incubated at room temperature, and then condensed using an ethanol/water (1:1) solvent. Four coating cycles in a 10% v/v titania sol produced homogeneous titania shells. The quality of catalysts was assessed quantitatively using Rietveld analysis of powder X-ray diffraction patterns combined with X-ray fluorescence spectrometry. During calcination, the anatase-to-rutile transformation was delayed to 1000 degrees C, which is similar to 300 degrees C higher than usually observed. The thermal stability and surface area of titania were enhanced through the slow crystal growth of anatase. The photocatalytic activity of the core-shell photocatalysts calcined at 400-600 degrees C was found to be proportional to the thickness of titania but did not directly correlate with the surface area.