Yan Panyu, Zhang Xinchao, Wang Xiaomei, Zhang Xu
Hebei Key Laboratory of Functional Polymers, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, P. R. China.
Langmuir. 2020 May 19;36(19):5271-5279. doi: 10.1021/acs.langmuir.0c00629. Epub 2020 May 6.
A unique structural transition from pomegranate-like monodisperse mesoporous silica microspheres (M-MSMs) with tunable mesopores to mesoporous silica microcapsules has been reported. The unique evolution occurred together with varying the cross-linking degrees (CLDs) of templates. Herein, using monodisperse sulfonated cross-linked polystyrene (S-CLPS) as templates, S-CLPS/SiO composite microspheres were synthesized by the sol-gel method. Subsequently, the templates were removed by calcination to obtain the M-MSMs or microcapsules. The pore sizes of M-MSMs could be tailored from 3.2 to 7.4 nm by facilely varying the CLDs from 0.5 to 20%. Interestingly, mesoporous silica microcapsules were gradually formed when the CLDs were beyond 20%. Meanwhile, the specific surface area also could be adjusted by this strategy without hardly affecting the monodispersity, and the specific surface area increased to 391.9 m/g. Significantly, Au@M-MSM was prepared by supporting Au nanoparticles (NPs) on M-MSM and used as nanocatalysts to reduce 4-nitrophenol (4-NP). The ultrathin shell and interconnected three-dimensional (3D) porous structure of M-MSMs can increase the mass transfer and protect the Au NPs from leakage, which reveals high recyclability and high conversion (>95%) after 10 regeneration-catalysis cycles. This approach provides a nanotechnology platform for the preparation of mesoporous silica materials with different microstructures, which will have enormous potential in practical applications involving different molecular sizes.
据报道，从具有可调介孔的石榴状单分散介孔二氧化硅微球（M-MSMs）到介孔二氧化硅微胶囊发生了独特的结构转变。这种独特的演变与模板交联度（CLDs）的变化同时发生。在此，以单分散磺化交联聚苯乙烯（S-CLPS）为模板，通过溶胶-凝胶法合成了S-CLPS/SiO复合微球。随后，通过煅烧去除模板以获得M-MSMs或微胶囊。通过将CLDs从0.5%轻松变化到20%，M-MSMs的孔径可以从3.2纳米调整到7.4纳米。有趣的是，当CLDs超过20%时，介孔二氧化硅微胶囊逐渐形成。同时，通过这种策略也可以调节比表面积，而几乎不影响单分散性，比表面积增加到391.9平方米/克。值得注意的是，通过在M-MSM上负载金纳米颗粒（NPs）制备了Au@M-MSM，并用作纳米催化剂来还原4-硝基苯酚（4-NP）。M-MSMs的超薄壳层和相互连接的三维（3D）多孔结构可以增加传质并保护金纳米颗粒不泄漏，这表明在10次再生催化循环后具有高可回收性和高转化率（>95%）。这种方法为制备具有不同微观结构的介孔二氧化硅材料提供了一个纳米技术平台，在涉及不同分子尺寸的实际应用中将具有巨大潜力。
