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首页> 外文期刊>Journal of Materials Chemistry, A. Materials for energy and sustainability >Surfactant-assisted synthesis of mesoporous silica/ ceria-siIica composites with high cerium content under basic conditions
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Surfactant-assisted synthesis of mesoporous silica/ ceria-siIica composites with high cerium content under basic conditions

机译：在碱性条件下表面活性剂辅助合成高铈含量的介孔二氧化硅/二氧化铈-二氧化硅复合材料

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Ordered mesoporous silica/ceria—silica composites were synthesized using cerium(iv) hydroxide and tetraethyl orthosilicate (TEOS) as co-precursors in the presence of hexadecyltrimethylammonium bromide (CTAB) under basic conditions. These composites consisted of Ce-doped mesoporous silica particles (about 500 nm) with highly ordered 2D hexagonal (p6mm) and 3D bicontinuous cubic (laid) structures and irregular ceria-rich silica—ceria particles. Wide angle XRD, diffuse reflectance UV-vis, and XPS analyses showed that 10-24% of cerium was at the Ce~(3+) oxidation level and the remaining predominant fraction of Ce was at the Ce~(4+) oxidation level. The cerium loading was varied in these composite materials up to 43 wt% (~3.1 mmol g~(-1)}. The specific surface areas of the mesoporous silica/ ceria-silica composite samples obtained on the basis of nitrogen adsorption isotherms were higher than 350 m~2 g~(-1) and their pore widths were between 3.3 and 3.5 nm. The mesoporous silica/ceria—silica samples were reduced at 850 °C under flowing H2 in a N2 environment. The crystal structure of the reduced samples changed to a hexagonally structured phase with the oxidation state of Ce~(3+), while the ordered mesostructure of silica was preserved.
机译：在碱性条件下，在十六烷基三甲基溴化铵（CTAB）存在下，使用氢氧化铈（iv）和原硅酸四乙酯（TEOS）作为共前体合成有序介孔二氧化硅/氧化铈-二氧化硅复合材料。这些复合材料由具有高度有序2D六角形（p6mm）和3D双连续立方（网格）结构的Ce掺杂介孔二氧化硅颗粒（约500 nm）和不规则的富含氧化铈的二氧化硅-氧化铈颗粒组成。广角XRD，漫反射紫外可见光和XPS分析表明，铈的10-24％位于Ce〜（3+）氧化水平，其余Ce的主要份额处于Ce〜（4+）氧化水平。这些复合材料中的铈含量变化最大为43 wt％（〜3.1 mmol g〜（-1）}。基于氮吸附等温线获得的介孔二氧化硅/二氧化铈-二氧化硅复合材料样品的比表面积较高大于350 m〜2 g〜（-1），孔宽在3.3〜3.5 nm之间;在氮气流下，在流动的氢气条件下，在850°C下还原了介孔二氧化硅/二氧化铈-二氧化硅样品。样品转变为具有Ce〜（3+）氧化态的六方结构相，同时保留了二氧化硅的有序介观结构。

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