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Astam K. Patra Arghya Dutta Prof. Dr. Asim Bhaumik 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(37):12388-12395
Mesoporous nanoparticles composed of γ‐Al2O3 cores and α‐Fe2O3 shells were synthesized in aqueous medium. The surface charge of γ‐Al2O3 helps to form the core–shell nanocrystals. The core–shell structure and formation mechanism have been investigated by wide‐angle XRD, energy‐dispersive X‐ray spectroscopy, and elemental mapping by ultrahigh‐resolution (UHR) TEM and X‐ray photoelectron spectroscopy. The N2 adsorption–desorption isotherm of this core–shell materials, which is of type IV, is characteristic of a mesoporous material having a BET surface area of 385 m2 g?1 and an average pore size of about 3.2 nm. The SEM images revealed that the mesoporosity in this core–shell material is due to self‐aggregation of tiny spherical nanocrystals with sizes of about 15–20 nm. Diffuse‐reflectance UV/Vis spectra, elemental mapping by UHRTEM, and wide‐angle XRD patterns indicate that the materials are composed of aluminum oxide cores and iron oxide shells. These Al2O3@Fe2O3 core–shell nanoparticles act as a heterogeneous Fenton nanocatalyst in the presence of hydrogen peroxide, and show high catalytic efficiency for the one‐pot conversion of cyclohexanone to adipic acid in water. The heterogeneous nature of the catalyst was confirmed by a hot filtration test and analysis of the reaction mixture by atomic absorption spectroscopy. The kinetics of the reaction was monitored by gas chromatography and 1H NMR spectroscopy. The new core–shell catalyst remained in a separate solid phase, which could easily be removed from the reaction mixture by simple filtration and the catalyst reused efficiently. 相似文献
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Dual‐Pore Mesoporous Carbon@Silica Composite Core–Shell Nanospheres for Multidrug Delivery 下载免费PDF全文
Yin Fang Prof. Gengfeng Zheng Jianping Yang Haosha Tang Yafeng Zhang Biao Kong Yingying Lv Prof. Congjian Xu Prof. Abdullah M. Asiri Prof. Jian Zi Prof. Fan Zhang Prof. Dongyuan Zhao 《Angewandte Chemie (International ed. in English)》2014,53(21):5366-5370
Monodispersed mesoporous phenolic polymer nanospheres with uniform diameters were prepared and used as the core for the further growth of core–shell mesoporous nanorattles. The hierarchical mesoporous nanospheres have a uniform diameter of 200 nm and dual‐ordered mesopores of 3.1 and 5.8 nm. The hierarchical mesostructure and amphiphilicity of the hydrophobic carbon cores and hydrophilic silica shells lead to distinct benefits in multidrug combination therapy with cisplatin and paclitaxel for the treatment of human ovarian cancer, even drug‐resistant strains. 相似文献
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Direct Assembly of Mesoporous Silica Functionalized with Polypeptides for Efficient Dye Adsorption 下载免费PDF全文
Yi‐Syuan Lu Dr. Bishnu Prasad Bastakoti Dr. Malay Pramanik Dr. Victor Malgras Prof. Yusuke Yamauchi Prof. Shiao‐Wei Kuo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(3):1159-1164
Herein, we introduce a new polypeptide‐functionalized mesoporous silica template fabricated from a biodegradable poly(ethylene oxide‐b‐?‐caprolactone) (PEO‐b‐PCL) diblock copolymer and a poly(tyrosine) (PTyr) biopolymer. The crystallization behavior of the PEO‐b‐PCL diblock copolymer changes after blending, but the secondary structure of PTry remains stable. After selective solvent extraction in THF, the PEO‐b‐PCL is removed, but PTyr remains within the silica matrix due to its different solubility. Fourier‐transform IR spectroscopic analysis (FTIR), thermal gravitometry analysis (TGA), small‐angle X‐ray scattering (SAXS), and X‐ray diffraction (XRD) studies confirm the retention of PTyr to form a polypeptide‐functionalized mesoporous material. The adsorption of methylene blue hydrate (MB) from aqueous solution into the polypeptide‐functionalized mesoporous silica is investigated, thus revealing that the nanocomposite exhibits a high adsorption capacity relative to pure silica due to hydrogen‐bonding interactions between the hydroxy phenolic group of PTyr and the N‐containing aromatic ring from MB. 相似文献
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Polystyrene‐core–silica‐shell hybrid particles were synthesized by combining the self‐assembly of nanoparticles and the polymer with a silica coating strategy. The core–shell hybrid particles are composed of gold‐nanoparticle‐decorated polystyrene (PS‐AuNP) colloids as the core and silica particles as the shell. PS‐AuNP colloids were generated by the self‐assembly of the PS‐grafted AuNPs. The silica coating improved the thermal stability and dispersibility of the AuNPs. By removing the “free” PS of the core, hollow particles with a hydrophobic cage having a AuNP corona and an inert silica shell were obtained. Also, Fe3O4 nanoparticles were encapsulated in the core, which resulted in magnetic core–shell hybrid particles by the same strategy. These particles have potential applications in biomolecular separation and high‐temperature catalysis and as nanoreactors. 相似文献
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A site‐selective controlled delivery system for controlled drug release is fabricated through the in situ assembly of stimuli‐responsive ordered SBA‐15 and magnetic particles. This approach is based on the formation of ordered mesoporous silica with magnetic particles formed from Fe(CO)5 via the surfactant‐template sol‐gel method and control of transport through polymerization of N‐isopropyl acrylamide inside the pores. Hydrophobic Fe(CO)5 acts as a swelling agent as well as being the source of the magnetic particles. The obtained system demonstrates a high pore diameter (7.1 nm) and pore volume (0.41 cm3 g?1), which improves drug storage for relatively large molecules. Controlled drug release through the porous network is demonstrated by measuring the uptake and release of ibuprofen (IBU). The delivery system displays a high IBU storage capacity of 71.5 wt %, which is almost twice as large as the highest value based on SBA‐15 ever reported. In vitro testing of IBU loading and release exhibits a pronounced transition at around 32 °C, indicating a typical thermosensitive controlled release. 相似文献
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Shape‐Controlled Surface‐Coating to Pd@Mesoporous Silica Core–Shell Nanocatalysts with High Catalytic Activity and Stability 下载免费PDF全文
Dr. Jie Ying Prof. Christoph Janiak Yu‐Xuan Xiao Hao Wei Prof. Xiao‐Yu Yang Prof. Bao‐Lian Su 《化学:亚洲杂志》2018,13(1):31-34
Cubic Pd nanocrystals with shape‐controlled mesoporous silica shells have been theoretically designed and successfully synthesized for investigating the effect of a porous nanoshell on catalytic performance of the core. Cubic Pd@cubic mesoporous silica keeps activity of all facets and shows highest catalytic activity and enhanced reusability in the hydrogenation of nitrobenzene. 相似文献
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Ultralight Mesoporous Magnetic Frameworks by Interfacial Assembly of Prussian Blue Nanocubes 下载免费PDF全文
Biao Kong Jing Tang Zhangxiong Wu Jing Wei Hao Wu Yongcheng Wang Prof. Gengfeng Zheng Prof. Dongyuan Zhao 《Angewandte Chemie (International ed. in English)》2014,53(11):2888-2892
A facile approach for the synthesis of ultralight iron oxide hierarchical structures with tailorable macro‐ and mesoporosity is reported. This method entails the growth of porous Prussian blue (PB) single crystals on the surface of a polyurethane sponge, followed by in situ thermal conversion of PB crystals into three‐dimensional mesoporous iron oxide (3DMI) architectures. Compared to previously reported ultralight materials, the 3DMI architectures possess hierarchical macro‐ and mesoporous frameworks with multiple advantageous features, including high surface area (ca. 117 m2 g?1) and ultralow density (6–11 mg cm?3). Furthermore, they can be synthesized on a kilogram scale. More importantly, these 3DMI structures exhibit superparamagnetism and tunable hydrophilicity/hydrophobicity, thus allowing for efficient multiphase interfacial adsorption and fast multiphase catalysis. 相似文献
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A solvothermal post‐treatment method was developed to synthesize Fe3O4@mesosilica core–shell nanospheres (CSNs) with a well‐preserved morphology, mesoporous structure, and tunable large pore diameters (2.5–17.6 nm) for the first time. N,N‐Dimethylhexadecylamine (DMHA), which was generated in situ during the heat‐treatment process, was mainly responsible for this pore‐size enlargement, as characterized by NMR spectroscopy. This pore‐size expansion can be strengthened with the aid of hexamethyldisilazane (HMDS), whilst the nature of the surface of the Fe3O4@mesosilica CSNs can be easily modified with trimethylsilyl groups during the pore‐size‐expansion process. The hydrophobicity of the Fe3O4@mesosilica CSNs increased for the enlarged mesopores and the adsorption capacity of these CSNs for benzene (up to 1.5 g g?1) is the highest ever reported for Fe3O4@mesosilica CSNs. The resultant Fe3O4@mesosilica CSNs (pore size: 10 nm) showed a 3.6‐times higher adsorption capacity of lysozyme than those without the pore expansion (pore size: 2.5 nm), thus making them a good candidate for loading large molecules. 相似文献
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介孔分子筛材料具有高的比表面积和孔体积、发达的孔结构、可控的形貌、表面基团可功能化、耐热、无毒无害等特点,以其为研究核心,在学术界和工业界均具有广泛的应用前景。通过模板法合成孔径在纳米范围的有序介孔硅材料,其具有从一维到三维高度规整的孔道结构,在吸附、分离、催化、生物医药工程等领域展现出巨大的应用潜能。利用具有几何和电子束缚特性的有序规整孔道作为微反应器来进行纳米结构主-客体组装,势必会显著增强其应用价值。本文以有序介孔硅材料规整孔道为基础和出发点,结合本课题组多年的研究结果,系统概述了近几年客体在有序介孔硅材料孔道内组装的进展,探讨了主-客体组装过程中的影响因素和合成机理。最后,着重对主-客体组装材料在环境净化和生物医药工程领域的应用进行概述。 相似文献
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A Highly Stable and Magnetically Recyclable Nanocatalyst System: Mesoporous Silica Spheres Embedded with FeCo/Graphitic Shell Magnetic Nanoparticles and Pt Nanocatalysts 下载免费PDF全文
Da Jeong Kim Dr. Yan Li Yun Jin Kim Prof. Nam Hwi Hur Prof. Won Seok Seo 《化学:亚洲杂志》2015,10(12):2755-2761
We have developed a highly stable and magnetically recyclable nanocatalyst system for alkene hydrogenation. The materials are composed of mesoporous silica spheres (MSS) embedded with FeCo/graphitic shell (FeCo/GC) magnetic nanoparticles and Pt nanocatalysts (Pt‐FeCo/GC@MSS). The Pt‐FeCo/GC@MSS have superparamagnetism at room temperature and show type IV isotherm typical for mesoporous silica, thereby ensuring a large enough inner space (surface area of 235.3 m2 g?1, pore volume of 0.165 cm3 g?1, and pore diameter of 2.8 nm) to undergo catalytic reactions. We have shown that the Pt‐FeCo/GC@MSS system readily converts cyclohexene into cyclohexane, which is the only product isolated and Pt‐FeCo/GC@MSS can be seperated very quickly by an external magnetic field after the catalytic reaction is finished. We have demonstrated that the recycled Pt‐FeCo/GC@MSS can be reused further for the same hydrogenation reaction at least four times without loss in the initial catalytic activity. 相似文献
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《化学:亚洲杂志》2017,12(20):2670-2674
The development of easy and affordable methods for the detection of cyanide is of great significance due to the high toxicity of this anion and the potential risks associated with its pollution. Herein, optical detection of cyanide in water has been achieved by using a hybrid organic–inorganic nanomaterial. Mesoporous silica nanoparticles were loaded with [Ru(bipy)3]2+, functionalized with macrocyclic nickel(II) complex subunits, and capped with a sterically hindering anion (hexametaphosphate). Cyanide selectively induces demetallation of nickel(II) complexes and the removal of capping anions from the silica surface, allowing the release of the dye and the consequent increase in fluorescence intensity. The response of the capped nanoparticles in aqueous solution is highly selective and sensitive towards cyanide with a limit of detection of 2 μm . 相似文献
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Shy‐Guey Wang Chia‐Wen Wu Prof. Kwunmin Chen Prof. Victor S.‐Y. Lin Prof. 《化学:亚洲杂志》2009,4(5):658-661
Three orientations to choose from : 2D hexagonal organically functionalized mesoporous silica nanoparticles with tunable mesochannel orientation (straight, helical, and radial mesochannels) were synthesized through a simple addition of various amounts of ureidopropyltrimethoxylsilane (UDPTMS) in the condensation of tetraorthosilicate (TEOS) in aqueous solution.
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A Mesoporous Superlattice Consisting of Alternately Stacking Interstitial Nanospace within Binary Silica Colloidal Crystals 下载免费PDF全文
Dr. Yoshiyuki Kuroda Yosuke Shimbo Prof. Yasuhiro Sakamoto Prof. Hiroaki Wada Prof. Kazuyuki Kuroda 《Angewandte Chemie (International ed. in English)》2016,55(36):10702-10706
A novel class of nonclassical structures of mesoporous silica, namely a binary nanoparticle mesoporous superlattice (BNMS), is obtained by the assembly of silica nanospheres of different sizes into a binary colloidal crystal. The colloidal crystal has a CrB‐type structure and consists of alternate stacks of unary fcc and binary AlB2‐type structures along the b axis and has four types of interstitial mesopores. The BNMS can be deposited on a substrate by dip coating to form an oriented thin film in which the direction of the superstructure (b axis) is perpendicular to the substrate. 相似文献
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Liang You Tianyi Wang Prof. Jianping Ge 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(6):2142-2149
An efficient and environment friendly surface‐protected etching method by using mesoporous silica as a template and alkaline polyelectrolyte as both the protecting and etching agent was developed to prepare a SiO2 nanotube with a porous shell. The polyelectrolytes attached to the template not only create a localized alkaline environment, but also effectively protect the silica surface, whereas the mesopore channels accelerate the diffusion of etchant throughout the template, all of which facilitate the formation of hollow structures in a fully controllable way. By tuning the etching power and protecting ability of the polyelectrolyte, the rigidity and porosity of products can be precisely manipulated. It is inspiring that various alkaline polyelectrolytes including polypeptide and dextran derivative can be used for the etching process, so that the porous and hollow nanostructures are born with positively charged and biocompatible surface as well as abundant amino groups for further coupling, which make them potential capsules for drug delivery and probes for imaging and detection. The protective etching process can also be extended to the preparation of yolk‐shell super structures with functional cores, or porous nanoparticle assemblies with their individual characteristics maintained. 相似文献