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首页> 外文期刊>Chemistry of Materials: A Publication of the American Chemistry Society >Formation of cubic Ia3d silicas and metal oxide-loaded silicas using a triblock copolymer (EO20PO70EO20) - Acetate mixture as structure director in aqueous solution
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Formation of cubic Ia3d silicas and metal oxide-loaded silicas using a triblock copolymer (EO20PO70EO20) - Acetate mixture as structure director in aqueous solution

机译：使用三嵌段共聚物（EO20PO70EO20）-醋酸盐混合物作为水溶液中的结构导向剂来形成立方晶型的Ia3d二氧化硅和负载金属氧化物的二氧化硅

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Mesoporous silica with Ia3d structure has been successfully prepared utilizing a triblock copolymer (EO20PO70EO20)-acetate mixture for structure direction in aqueous solution over a wide pH range, even above the isoelectric point of silica, where the pH value could be finely tuned by varying the concentration of HCl and/or acetate. Characterization by XRD, TEM, and N-2 sorption measurements show that the cubic Ia3d materials possess high surface areas (about 900 m(2)/g), large pore volumes (about 1.2 cm(3)/g), and uniform pore diameters (about 9.2 nm). Further, the phase diagram in the SiO2-P123-ZnAc2-H2O-HCl system is drawn to map the range of cubic mesophase. Salt effect has been investigated during the phase transformation process, which reveals that the nature and concentration of cations can also determine the mesostructure. In addition, when two different acetates are introduced into the solution at one time, metal oxides-modified cubic mesoporous silica can be directly synthesized. Among others, copper-modified cubic samples, prepared by this direct method, display superior properties in the NO2-TPD experiments. The lower acid concentration in the acetate-modulated synthetic system favors the direct incorporation of metal oxide species and this discovery may offer us a new perspective to better understand the formation mechanism of ordered mesoporous materials.
机译：已经成功地使用三嵌段共聚物（EO20PO70EO20）-乙酸盐混合物在宽pH范围内，甚至在二氧化硅的等电点以上通过水溶液中的结构方向成功制备了具有Ia3d结构的中孔二氧化硅，其中可以通过改变pH值来微调pH值。 HCl和/或乙酸盐的浓度。通过XRD，TEM和N-2吸附测量表征表明，立方Ia3d材料具有高表面积（约900 m（2）/ g），大孔体积（约1.2 cm（3）/ g）和均匀的孔直径（约9.2 nm）。此外，绘制了SiO2-P123-ZnAc2-H2O-HCl系统中的相图以绘制立方中间相的范围。在相变过程中研究了盐效应，这表明阳离子的性质和浓度也可以决定介观结构。另外，当一次将两种不同的乙酸盐引入溶液中时，可以直接合成金属氧化物改性的立方中孔二氧化硅。其中，通过这种直接方法制备的铜改性立方样品在NO2-TPD实验中显示出优异的性能。乙酸盐调节的合成体系中较低的酸浓度有利于金属氧化物种类的直接结合，这一发现可能为我们提供一个新的视角，以更好地了解有序介孔材料的形成机理。

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