铁基无机介孔材料

铁基无机介孔材料因其环境友好、成本低廉及独特磁性与化学活性等优点而备受关注,并在众多领域展现出巨大的应用前景。本文综述了近年来铁基无机介孔材料的合成及其应用研究,重点归纳评述了各类铁基无机介孔材料（如介孔水合氧化铁、介孔氧化铁、介孔硅酸铁、介孔磷酸铁、铁基介观晶体、Fe/Si（C、Al、Ti）复合物等）的制备技术和结构特性;概括并讨论了铁基无机介孔材料在催化、吸附、气体传感、锂离子电池、医药、主客体合成等领域的应用技术;分析了目前铁基无机介孔材料研究存在的问题并总结了未来的研究方向。     

介孔碳纳米纤维为载体的铂催化剂的制备及电化学性质

本文利用介孔碳的软模板合成方法和阳极氧化铝膜的孔道限域性制备有序的介孔碳纳米纤维。然后以介孔碳纳米纤维作载体,采用温和的非共价方法和乙二醇还原法负载铂纳米粒子来制备铂催化剂。实验结果表明,温和的功能化方法有利于载体介孔结构的保持和铂纳米粒子的分散,并且还原反应条件对铂纳米粒子的负载具有重要影响。最后通过循环伏安法研究了铂催化剂的电化学性质,结果表明这些铂催化剂具有良好的甲醇电催化活性和稳定性。     

介孔微环境对客体发光性能的影响

介孔材料具有均一的纳米级孔道、大的比表面积、稳定的骨架结构以及易于修饰的内表面,被广泛用作客体物质的载体。对于通过在介孔材料中封装稀土配合物、无机金属氧化物、含芳环有机物等得到的复合发光材料的发光性能已有广泛研究。综述了此类复合发光材料的制备方法、测试方法等的进展,并重点讨论了介孔微环境对客体发光性能的影响。     

介孔二氧化硅基智能递送体系的构建及其在各类疾病治疗中的应用

利用先进纳米技术开发的药物递送体系能够改善药物的理化性质和治疗效果,同时削弱其毒副作用,因而纳米药物递送体系成为现代药剂学研究的热点和主流方向。其中,介孔二氧化硅作为纳米载体的基质材料具有比表面积大、形貌结构可调、表面易于修饰及生物相容性良好等优点,引发生物医学研究人员的广泛关注,为构筑新型智能药物递送体系提供了新的设计思路。本文就介孔二氧化硅基智能递送体系在设计构筑和疾病治疗应用等方面的最新研究进展进行了综述。首先,本文对介孔硅的发展历程、制备方法及结构特性进行了简要概述;其次,从药物装载和门控释放两大角度系统阐述了近些年介孔硅基智能递送体系的构建策略,重点介绍了各种刺激响应性介孔硅基递送体系的门控开关(如聚合物、无机纳米颗粒、超分子组装体及生物大分子等)及其可控释放机制;随后,详细描述了介孔硅基控释体系在各种类型疾病(包括癌症、细菌感染、糖尿病和阿尔茨海默病等)治疗中的应用进展;最后,总结和分析了介孔硅基智能纳米载体研究中存在的问题并对其未来发展作了展望。     

由沸石纳米粒子自组装制备具有高催化活性中心和水热稳定的新型介孔分子筛材料

 人们合成了一系列介孔分子筛材料，并发现它们在催化、吸附与分离以及化学组装制备先进材料和分子器件等方面具有很大的潜在应用价值．但是，介孔分子筛材料相对于微孔沸石分子筛存在着两个致命弱点：较低的水热稳定性和较不活泼的催化活性中心．这两个弱点大大地影响了介孔分子筛在催化反应中的广泛应用．本文系统地综述了最近几年利用沸石纳米粒子自组装制备具有高催化活性中心和水热稳定的介孔分子筛材料的研究进展．这包括利用硅铝沸石纳米粒子自组装制备具有强酸性和水热稳定的新型介孔硅铝分子筛材料，利用钛硅沸石纳米粒子自组装制备具有高催化氧化活性中心和水热稳定的新型钛硅介孔分子筛材料，以及利用含有不同杂原子的沸石纳米粒子自组装制备一系列水热稳定的新型介孔分子筛催化材料．     

有序介孔氧化硅薄膜制备及其组装化学

本文综述了近年来利用有机模板法合成有序介孔二氧化硅薄膜的研究进展，重点阐述了两相界面外延生长和蒸发诱导自组装两种制备方法及其合成机理。此外，讨论了有序介孔二氧化硅薄膜的组装化学，包括金属元素掺杂，纳米粒子在介孔薄膜中的组装，以及有机物/二氧化硅纳米复合薄膜的制备，并对介孔二氧化硅薄膜未来的发展趋势做了展望。     

中空纳米二氧化硅微球的制备及表征

本文介绍了一种制备中空纳米二氧化硅微球的新方法。利用模板首先合成介孔纳米二氧化硅微球,再用水热反应法,成功制备了非功能化和巯基、氨基功能化中空纳米二氧化硅微球。利用透射电子显微镜,热重分析等手段对其形貌进行了表征。另外,对中空介孔纳米二氧化硅微球的形成机制进行了探讨。     

含钴介孔分子筛催化热解乙醇制备纳米碳管

以CTAB为模板剂,硅酸钠、氯化钴为原料,通过水热法合成含钴介孔分子筛(Co-MCM-41)。以所合成的Co-MCM-41做催化剂,采用化学气相沉积(CVD)法催化热解乙醇制备纳米碳管。通过XRD、FT-IR、TEM、N2吸附-脱附和Raman光谱等分析手段对所合成的介孔分子筛和纳米碳管进行了表征。结果表明:合成的Co-MCM-41样品具有MCM-41的介孔结构,比表面积较大且介孔有序性较好。以所合成的含钴介孔分子筛催化热解乙醇制备出管径均匀、管壁较厚、顶端开口的多壁纳米碳管。     

负载Co介孔分子筛催化热解乙醇制备纳米碳管

以硅酸钠为原料,CTAB为模板剂,水热法合成MCM-41介孔分子筛,采用浸渍法制备负载钴的介孔分子筛(Co/MCM-41),并将其作为催化剂,CVD法热解无水乙醇制备CNTs.利用XRD、TEM、比表面积和孔径分布测定和Raman光谱等方法对所合成的介孔分子筛和纳米碳管进行了表征.结果表明:所制备的Co/MCM-41样品具有典型的MCM-41的介孔结构;当热解反应温度为750℃下所制备出的纳米碳管的品质最好.     

以手性两亲小分子为模板剂制备介孔二氧化硅纳米空心球

以L-亮氨酸为手性源合成了手性阳离子两亲性小分子化合物L-18Leu6NEtBr,用其自组装体作为模板,氢氧化钠为催化剂,经溶胶-凝胶过程制备出介孔二氧化硅纳米空心球;分析了介孔二氧化硅纳米空心球的尺寸和孔径.结果表明,所制备的二氧化硅空心球直径约100nm;其介孔孔道平行于壳表面,孔径为3.1nm.     

Methyl orange degradation enhanced by hydrogen spillover onto platinum nanocatalyst surface

Following a thermal reduction method, platinum nanoparticles were synthesized and stabilized by polyvinylpyrrolidone. The colloidal platinum nanoparticles were stable for more than 3 months. The micrograph analysis unveiled that the colloidal platinum nanoparticles were well dispersed with an average size of 2.53 nm. The sol–gel‐based inverse micelle strategy was applied to synthesize mesoporous iron oxide material. The colloidal platinum nanoparticles were deposited on mesoporous iron oxide through the capillary inclusion method. The small‐angle X‐ray scattering analysis indicated that the dimension of platinum nanoparticles deposited on mesoporous iron oxide (Pt‐Fe₂O₃) was 2.64 nm. X‐ray photoelectron spectroscopy (XPS) data showed that the binding energy on Pt‐Fe₂O₃ surface decreased owing to mesoporous support–nanoparticle interaction. Both colloidal and deposited platinum nanocatalysts improved the degradation of methyl orange under reduction conditions. The activation energy on the deposited platinum nanocatalyst interface (2.66 kJ mol^?1) was significantly lowered compared with the one on the colloidal platinum nanocatalyst interface (40.63 ± 0.53 kJ mol^?1).     

Dissolution of iron oxide nanoparticles inside polymer nanocapsules

The structure of poly(organosiloxane) nanocapsules partially filled with iron oxide cores of different sizes was revealed by small angle X-ray scattering and X-ray diffraction. The nanocapsules are synthesized by the formation of a poly(organosiloxane) shell around iron oxide nanoparticles and the simultaneous partial dissolution of these cores. Due to the high scattering contrast of the iron oxide cores compared to the polymer shell, the particle size distribution of the cores inside the capsules can be measured by small angle X-ray scattering. Additional information can be revealed by X-ray diffraction, which gives insights into the formation of the polymer network and the structure of the iron oxide cores. The study shows how the crystallinity and size of the nanoparticles as well as the shape and width of the size distribution can be altered by the synthesis parameters.     

Recent Advances in Inorganic Nanomaterials Synthesis Using Sonochemistry: A Comprehensive Review on Iron Oxide,Gold and Iron Oxide Coated Gold Nanoparticles

Sonochemistry uses ultrasound to improve or modify chemical reactions. Sonochemistry occurs when the ultrasound causes chemical effects on the reaction system, such as the formation of free radicals, that intensify the reaction. Many studies have investigated the synthesis of nanomaterials by the sonochemical method, but there is still very limited information on the detailed characterization of these physicochemical and morphological nanoparticles. In this comprehensive review, recent advances in the sonochemical synthesis of nanomaterials based on iron oxide nanoparticles (Fe₃O₄NP), gold nanoparticles (AuNP) and iron oxide-coated gold nanoparticles (Fe₃O₄@Au NP) are discussed. These materials are the most studied materials for various applications, such as medical and commercial uses. This review will: (1) address the simple processing and observations on the principles of sonochemistry as a starting point for understanding the fundamental mechanisms, (2) summarize and review the most relevant publications and (3) describe the typical shape of the products provided in sonochemistry. All in all, this review’s main outcome will provide a comprehensive overview of the available literature knowledge that promotes and encourages future sonochemical work.     

Fe-containing nanocomposites based on a biocompatible copolymer 1-vinyl-1,2,4-triazole with <Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone

New polymer nanocomposites containing iron oxide nanoparticles stabilized with a biocompatible copolymer of 1-vinyl-1,2,4-triazole with N-vinylpyrrolidone were produced. The synthesis was conducted using the method of chemical reduction of iron ions with hydrazine hydrate in an aqueous medium in the presence of a polymer matrix. The ESR spectroscopy data showed that the core—shell type nanoparticles were obtained. The core generally consistsed of zero-valence iron coated with an oxide shell. According to the data of transmission electron microscopy, the obtained polymer nanocomposites consisted of nanoparticles of mainly spherical shape with a diameter from 1 to 14 nm. Aggregates formed from individual stabilized nanoparticles of up to 75 nm in size (in most cases) were also observed. These aggregated particles were found to self-organize and form branched chains. Nanocomposites were characterized by a different particle-size distribution, which was determined by the initial ratio of the copolymer and the precursor of iron nanoparticles.     

Iron Oxide Nanoparticles Embedded onto 3D Mesochannels of KIT‐6 with Different Pore Diameters and Their Excellent Magnetic Properties

Here, we report the results of our detailed study on the fabrication of iron oxide magnetic nanoparticles confined in mesoporous silica KIT‐6 with a 3D structure and large, tunable pore diameters. It was confirmed by XRD, nitrogen adsorption, high‐resolution (HR) TEM, and magnetic measurements that highly dispersed iron oxide nanoparticles are occupied inside the mesochannels of KIT‐6. We also demonstrated that the size of the iron oxide nanoparticle can be controlled by simply changing the pore diameter of the KIT‐6 and the weight percentage of the iron oxide nanoparticles. The effect of the weight percentage and size of the iron oxide nanoparticles, and the textural parameters of the support on the magnetic properties of iron oxide/KIT‐6 has been demonstrated. The magnetization increases with decreasing iron content in the pore channels of KIT‐6, whereas coercivity decreases for the same samples. Among the KIT‐6 materials studied, KIT‐6 with 7.5 wt % of iron showed the highest saturation magnetic moment and magnetic remanence. However, all the samples register a coercivity of around 2000 Oe, which is generally observed for the hard magnetic materials. In addition, we have found a paramagnetic‐to‐superparamagnetic transition at low temperature for samples with different iron content at low temperature. The cause for this exciting transition is also discussed in detail. Magnetic properties of the iron oxide loaded KIT‐6 were also compared with pure iron oxide and iron oxide loaded over SBA‐15. It was found that iron oxide loaded KIT‐6 showed the highest magnetization due to its 3D structure and large pore volume. The pore diameter of the iron oxide loaded KIT‐6 support also plays a critical role in controlling the magnetization and the blocking temperature, which has a direct relation to the particle diameter and increases from 48 to 63 K with an increase in the pore diameter of the support from 8 to 11.3 nm.     

Synthesis of aligned hematite nanoparticles on chitosan–alginate films

Iron oxide nanoparticles are being viewed with interest owing to the great potential they have in the biomedical applications like MRI contrast enhancement, targeted drug delivery, hyperthermia and recently in magnetic separation of cancer cells from the body. Templated synthesis has been considered ideal for synthesis of iron oxide nanoparticles as particles are attracted magnetically, in addition to usual flocculation through van der Waals attraction. Biological templates are attractive owing to their biocompatibility and the attractive porosity and surface chemistry that nature provides. Polysaccharides like chitosan and alginate have been employed in the synthesis of a polyion complex, which provided the active-binding sites for iron(II) ions in solution to bind. The natural organization of chitosan and alginate into a porous film has been exploited to synthesize spherical iron oxide nanoparticles through careful calcination of the iron(II) conjugate film. Our experiments indicate that the formed nanoparticles are highly crystalline, confirm to the hematite structure and have a superparamagnetic response with a low coercivity of 116 Oe. Particles thus synthesized were highly monodisperse with hydrodynamic diameter of 1.8 nm. The symmetric porosity of the film translates into the synthesis of well-aligned nanoparticles of iron oxide. Compared to synthesis in solution, the film-assisted synthesis offered a greater degree of control over the particle size distribution pattern, with the chitosan–alginate template providing the needed spatial separation to prevent the aggregation due to magnetostatic coupling. Such hematite nanoparticles can either be used directly or converted to paramagnetic magnetite by reduction. Zeta potential measurements indicate highly stable nanoparticles, which can therefore be conjugated to cationic liposomes carrying drugs and magnetically guided to target sites.     

Highly active heterogeneous Fenton catalyst using iron oxide nanoparticles immobilized in alumina coated mesoporous silica

A highly active heterogeneous Fenton catalyst was fabricated by impregnating iron oxide nanoparticles in alumina coated mesoporous SBA-15 silica.     

Colloidal Metal Nanocatalysts: Synthesis,Characterization, and Catalytic Applications

Metal nanoparticles are key materials in heterogeneous catalysis due to their high catalytic activity and selectivity to the desired product. Accordingly, they are playing a pivotal role in most heterogeneous catalytic reactions that are steeply growing with the development of a colloidal synthetic protocol that enables fine control of size, shape, morphology and composition of metal nanoparticles at an atomic level. These colloidal metal nanoparticles can be dispersed on a rigid support such as mesoporous silica, metal oxide and zeolite, which utilizes metal nanoparticles as model heterogeneous catalysts in industrially important processes involving hydrogenation/dehydrogenation, isomerization and cracking. In this review article, we highlight the recent progress on general colloidal synthetic routes with technological advances in characterization tools that enable the atomic-scale observation of metal nanoparticles. Structure-dependent contributions on the control of product selectivity and turnover rate are also discussed by combining advanced ex situ and in situ surface characterization tools that can monitor the structural change of metal nanocatalysts as well as the evolution of reaction intermediates under the reaction conditions.     

Mesoporous silica-magnetite nanocomposite: facile synthesis route for application in hyperthermia

The synthesis of nanostructured magnetic materials has been intensively researched because of their large field of applications as magnetic carriers in drug targeting, hyperthermia in tumor treatment, among others. Much effort has been invested in magnetic nanoparticles for bioapplications. However, as these nanoparticles present high specific surface area, unprotected nanoparticles can easily form aggregates and react with oxygen in the air. They can also rapidly biodegrade when directly exposed to biological systems. In this context, we have explored the possibility of synthesizing a mesoporous SiO₂–Fe₃O₄ nanocomposite and its AC magnetic-field-induced heating properties. The magnetite nanocomposite was obtained by impregnation of an iron precursor into a silica framework. The proposed method involves the preparation of an iron oxide precursor in ethanol and the subsequent impregnation of SBA-15 mesoporous hexagonal silica. Iron oxide was formed inside the porous structure, thus producing the magnetic device. The nanocomposite was characterized by X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), N₂ adsorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Measurements of AC magnetic-field-induced heating properties of the obtained nanocomposite, both of the solid form and in aqueous solution, under different applied magnetic fields showed that it is suitable as a hyperthermia agent for biological applications.     

Tunable magnetic arrangement of iron oxide nanoparticles in situ synthesized on the solid substrate from diblock copolymer micelles

Hexagonal arrangement of iron oxide nanoparticles was fabricated by utilizing a single-layered film of diblock copolymer micelles. The synthesis was directly performed on the solid substrate by oxygen plasma with preserving the dimensional order of micelles so that separate procedures for synthesis and deposition of nanoparticles were not necessary. Since the oxygen plasma treatment also eliminated polymers, pure patterns of iron oxide nanoparticles were obtained. Moreover, easy control over the size of nanoparticles enabled us to selectively create a ferrimagnetic or a superparamagnetic pattern of iron oxide nanoparticles without altering the fabrication process.