An organosilane-directed growth-induced etching strategy for preparing hollow/yolk–shell mesoporous organosilica nanospheres with perpendicular mesochannels and amphiphilic frameworks
An organosilane-directed growth-induced etching strategy for preparing hollow/yolk–shell mesoporous organosilica nanospheres with perpendicular mesochannels and amphiphilic frameworks
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DOI：
10.1039/c4ta01943a
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发表时间：
2014-07
影响因子：
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通讯作者：
Houbing Zou;Runwei Wang;Xiaoxin Li;Xue Wang;Shangjing Zeng;S. Ding;Lu Li;Zongtao Zhang;S. Qiu
中科院分区：
文献类型：
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作者：
Houbing Zou;Runwei Wang;Xiaoxin Li;Xue Wang;Shangjing Zeng;S. Ding;Lu Li;Zongtao Zhang;S. Qiu
我们开发了一种有机硅烷定向生长诱导蚀刻策略，以制备具有垂直介孔通道、透明中空内部以及两亲性框架的中空周期性介孔有机二氧化硅（PMO）纳米球。这种策略简单、高效、可控性强。以二氧化硅纳米球为硬模板，通过一步路线获得空心PMO纳米球，通过调整合成条件高度控制结构参数。采用不同的有机硅烷得到不同有机基团的桥联空心PMO纳米球，并表现出不同的定向容量。通过傅里叶变换红外（FT-IR）光谱和固态13C核磁共振（NMR）光谱证实了桥连有机基团的完整性。透射电子显微镜 (TEM) 观察表明，每个纳米球的 PMO 壳的生长和二氧化硅纳米球核的溶解同时发生，而 29Si NMR 谱显示，二氧化硅纳米球中溶解的二氧化硅物质通过与水解的有机硅烷低聚物共缩合转化为 PMO 壳。结果，获得的空心纳米球具有两亲性，甚至可以用作各种体系中O-W或W-O乳液的颗粒乳化剂。这些材料还可以用作去除水中疏水污染物的有效吸附剂。利用所提出的形成机制，该策略可以扩展为将二氧化硅涂覆的复合材料转化为具有功能性内部核心和垂直介孔两亲壳的蛋黄壳结构。作为纳米反应器，-Ph-桥接的两亲壳在水中表现出比亲水性二氧化硅壳更快的有机反应物扩散速率，因此对4-硝基苯酚的还原具有更好的催化活性。
We have developed an organosilane-directed growth-induced etching strategy to prepare hollow periodic mesoporous organosilica (PMO) nanospheres with perpendicular mesoporous channels and a clear hollow interior as well as an amphiphilic framework. This facile strategy is simple, efficient, and highly controllable. Silica nanospheres were utilized as hard templates to obtain hollow PMO nanospheres through a one-step route, with the structure parameter highly controlled by adjusting the synthesis conditions. Different organosilanes were used to obtain bridged hollow PMO nanospheres of different organic groups and showed different directed capacities. The integrity of the bridged organic group was confirmed by Fourier-transform infrared (FT-IR) spectroscopy and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Transmission electron microscopy (TEM) observations showed that the growth of the PMO shell and the dissolution of the silica nanosphere core occurred simultaneously for each nanosphere, while 29Si NMR spectra revealed that the dissolved silica species from the silica nanospheres transformed into PMO shells by co-condensation with hydrolyzed organosilane oligomers. As a result, the obtained hollow nanospheres were amphiphilic, which can even be used as a particle emulsifier for O–W or W–O emulsion in various systems. These materials can also be served as an efficient sorbent for removal of hydrophobic contaminants in water. Using the proposed formation mechanism, this strategy can be extended to transform silica-coated composite materials into yolk–shell structures with a functional interior core and a perpendicular mesoporous amphiphilic shell. As a nanoreactor, the –Ph– bridged amphiphilic shell showed a faster diffusion rate for organic reactants in water than the hydrophilic silica shell, and thus better catalytic activity for reduction of 4-nitrophenol.