氮氧化硅材料的研究进展

综述了近几年氮氧化硅复合材料、氮氧化硅薄膜材料和介孔氮氧化硅材料的研究与发展现状。着重介绍了氮氧化硅薄膜材料的发光特性和折射率可调特性,及其不同的制备方法。同时介绍了介孔氮氧化硅材料和Si_3N_4/Si_2N_2O、SiC/Si_2N_2O及BN/SiNOf三种应用较多的氮氧化硅复合材料的研究现状。并对氮氧化硅材料的研究与应用进行了展望。     

静电纺介孔氧化硅基纳米纤维的研究进展

介孔氧化硅是最为典型的介孔材料,其具有比表面积高、孔径均一、易于表面修饰等优异特性,广泛应用于吸附分离、催化、传感以及物质负载与缓释等领域。关于粉体和薄膜形态的介孔氧化硅已有大量报道,但纤维形态,特别是连续纤维形态的介孔氧化硅材料的制备仍然是一项挑战。近年来随着静电纺技术的发展,连续纤维形貌的介孔氧化硅材料的制备取得了重要进展。根据纤维介孔结构的有序度和介孔结构引入方式的不同,对静电纺介孔氧化硅基纳米纤维进行详细的介绍。     

以嵌段共聚物为结构导向剂的SBA-15和SBA-16的合成及表征

利用嵌段共聚物P123和F127分别在强酸性条件下合成了两种结构不同的介孔氧化硅材料一维直孔道六方相的SBA-15和三维立方相的SBA-16,并通过XRD、N2吸附-脱附、HTEM等手段对材料进行了研究.结果表明商品化的嵌段共聚物作为结构导向剂合成的介孔氧化硅材料SBA-15和SBA-16孔道规整有序,比表面积分别达到765m2.g-1和930m2.g-1,相应的最可几孔径分别为6.46nm和3.92nm,这有利于介孔材料向经济实用方向发展.     

同步辐射的基本知识第三讲同步辐射中的散射术及其应用（五）

4介孔材料的X射线分析介孔（meso-porous）材料是一种特殊材料，1992年，美国Mobil公司的Kresge首次在Natrure杂志报导一类硅铝酸盐为基的新颖介孔氧化硅材料。介孔氧化硅材料的基本合成过程为：将表面活化剂、酸或碱加入水中组成混合溶液，然后向其中加入硅源或其他物质源，反应所得产物经水-热处理或室温陈化后，进行洗涤和过滤等处理，最后经煅烧或化学处理过程除去有机表面活性剂，得到只有无机骨架结构的介孔材料。     

缓冲溶液中制备掺杂高度隔离铁物种的介孔氧化硅(英文)

使用P123作为模板剂,采用不同的硅源(正硅酸甲酯,正硅酸乙酯,硅酸钠)在弱酸性的条件下(pH=4.4,乙酸-乙酸钠缓冲溶液)合成掺杂铁的介孔氧化硅材料.正硅酸甲酯和硅酸钠形成有序的二维六方相的介孔结构,而正硅酸乙酯形成了囊泡结构.紫外可见漫反射光谱和紫外共振拉曼光谱表明,在环境友好的条件下,采用硝酸铁和硅酸钠可以合成出高度隔离的铁物种.缓冲溶液提供了一条便捷的途径,通过简单改变硅源来控制介孔结构.掺杂铁的介孔氧化硅材料在苯酚的羟化反应中表现出优异的催化性能,主要由于铁物种高度分散在氧化硅载体上,介孔结构使铁活性位更易于接近反应物分子.     

水热法合成介孔氧化硅材料的结构及表面特性

以十六烷基三甲基溴化氨 (CTMABr)为模板剂 ,利用碱性水热法制备了介孔氧化硅材料 ,并采用小角度XRD、HRTEM、BET和FT IR等测试手段研究了其孔的结构、表面N2 吸附特性和孔径分布情况。结果表明 :碱性水热法制得的介孔氧化硅材料具有规则的六方结构 ,介孔的最可几半径为 1 9mm ,比表面积为 5 42 8m2 / g ,孔容为 0 4 5 6cm3/ g。     

磁性微/纳米材料吸附环境污染物的研究进展

就功能化铁氧化物、磁性微/纳米碳材料、磁性介孔氧化硅材料以及其它磁性微/纳米材料吸附环境污染物的应用进行评述.     

介孔稀土氧化物的合成研究进展

介孔稀土氧化物由于在催化、光、电、磁等领域具有巨大应用潜力,已逐渐成为一个研究的热点.介绍了介孔材料的合成机理,较全面地综述了近年来合成介孔稀土氧化物的几种方法及最新研究进展.通过各种物理表征结果考察了合成条件对介孔材料的性质和形貌的影响,指出了目前介孔稀土氧化物制备方面存在的一些问题,对其应用前景进行了展望.     

介孔碳的合成及其在吸附中的应用研究进展

阐述了有序介孔碳材料的合成方法及各自的特点,总结了有序介孔碳在生物大分子、重金属离子和合成有机污染物吸附领域的应用情况,并展望了有序介孔碳材料在合成方法、表面改性及其在吸附应用方面的发展趋势.     

介孔泡沫及手性介孔材料的制备与应用

介孔泡沫材料具有超大介孔、开放式孔结构、孔径可调等特点,在催化剂载体、酶固定等领域具有明显的优势.手性介孔材料除了具有常规介孔材料的特点外还具有手性,因此在立体化学领域具有潜在的研究与应用价值.综述了介孔泡沫材料以及手性介孔材料的合成与应用.     

Chemistry of Mesoporous Organosilica in Nanotechnology: Molecularly Organic–Inorganic Hybridization into Frameworks

Organic–inorganic hybrid materials aiming to combine the individual advantages of organic and inorganic components while overcoming their intrinsic drawbacks have shown great potential for future applications in broad fields. In particular, the integration of functional organic fragments into the framework of mesoporous silica to fabricate mesoporous organosilica materials has attracted great attention in the scientific community for decades. The development of such mesoporous organosilica materials has shifted from bulk materials to nanosized mesoporous organosilica nanoparticles (designated as MONs, in comparison with traditional mesoporous silica nanoparticles (MSNs)) and corresponding applications in nanoscience and nanotechnology. In this comprehensive review, the state‐of‐art progress of this important hybrid nanomaterial family is summarized, focusing on the structure/composition–performance relationship of MONs of well‐defined morphology, nanostructure, and nanoparticulate dimension. The synthetic strategies and the corresponding mechanisms for the design and construction of MONs with varied morphologies, compositions, nanostructures, and functionalities are overviewed initially. Then, the following part specifically concentrates on their broad spectrum of applications in nanotechnology, mainly in nanomedicine, nanocatalysis, and nanofabrication. Finally, some critical issues, presenting challenges and the future development of MONs regarding the rational synthesis and applications in nanotechnology are summarized and discussed. It is highly expected that such a unique molecularly organic–inorganic nanohybrid family will find practical applications in nanotechnology, and promote the advances of this discipline regarding hybrid chemistry and materials.     

晶态过渡金属氧化物介孔材料的合成进展

过渡金属氧化物介孔材料是继介孔氧化硅之后引起广泛关注的研究热点,而晶态时过渡金属氧化物介孔材料的性质及广泛应用起着决定性的作用.从合成角度综述了硬模板和软模板法制备有序晶态过渡金属氧化物介孔材料的研究进展,并且展望了介孔材料的发展趋势.硬模板法制备的介孔材料比软模板法有更好的有序性,而软模板法合成过程简便,有更好的工业应用前景,但需解决材料的有序介孔结构热稳定性差的难题.     

介孔二氧化硅纳米复合材料的研究进展

介绍了近年来介孔二氧化硅复合材料的研究趋势与发展方向。介孔二氧化硅材料作为研究时间最长、技术最成熟的介孔材料,对整个介观材料的理论和材料设计具有重要意义。阐述了介孔二氧化硅材料的主要合成方法及其原理,着重从材料复合方式以及相应材料的特点、相关应用等方面的研究进展进行了综述,探讨了现有的问题,并且对未来介孔材料的发展趋势进行了展望。     

药物在有序介孔氧化硅纳米孔道中组装与控缓释研究进展

有序介孔纳米氧化硅材料是一种越来越受到重视的新型药物控缓释栽体材料.综述了其与作为药物控缓释载体用途相关的控制性合成的进展以及其纳米孔道结构特性对纳米孔道中药物分子组装、控缓释行为的影响,为控缓释药物研究人员研究药物分子的控缓释行为和药物分子组装技术及开发新型药物分子载体材料提供研究依据.     

埃洛石原料无模板法制备高比表面积介孔氧化硅及其在亚甲基蓝吸附中的应用

采用无模板法, 以天然的矿物原料制备介孔材料是一种经济有效的制备方法。本研究利用“煅烧-沸石化-酸处理”工艺制备高比表面积的介孔氧化硅颗粒。研究发现,通过长时间的碱处理将煅烧埃洛石转化为沸石,随后通过酸处理,可制备出比表面积高达767 m²/g的介孔氧化硅材料。该工艺机理为: 850℃煅烧使埃洛石转变为无定型态的Si-O-Al网络结构,煅烧埃洛石在长时间的水热碱处理过程中转化为结晶态的LTA沸石硅铝酸钠,在随后的强酸性环境下,沸石的Al-O和Na-O成分被完全溶解,而残余的Si-O纳米碎片在酸环境中相互聚合,生成无定形态的介孔氧化硅颗粒。本实验制备的介孔氧化硅比表面积高达767 m²/g,最可几孔径为5 nm,其亚甲基蓝平衡吸附量可达741 mg/g,表明其在污染物吸附中具有良好的应用潜力。     

Recent Progress in the Synthesis of Porous Carbon Materials

In this review, the progress made in the last ten years concerning the synthesis of porous carbon materials is summarized. Porous carbon materials with various pore sizes and pore structures have been synthesized using several different routes. Microporous activated carbons have been synthesized through the activation process. Ordered microporous carbon materials have been synthesized using zeolites as templates. Mesoporous carbons with a disordered pore structure have been synthesized using various methods, including catalytic activation using metal species, carbonization of polymer/polymer blends, carbonization of organic aerogels, and template synthesis using silica nanoparticles. Ordered mesoporous carbons with various pore structures have been synthesized using mesoporous silica materials such as MCM‐48, HMS, SBA‐15, MCF, and MSU‐X as templates. Ordered mesoporous carbons with graphitic pore walls have been synthesized using soft‐carbon sources that can be converted to highly ordered graphite at high temperature. Hierarchically ordered mesoporous carbon materials have been synthesized using various designed silica templates. Some of these mesoporous carbon materials have successfully been used as adsorbents for bulky pollutants, as electrodes for supercapacitors and fuel cells, and as hosts for enzyme immobilization. Ordered macroporous carbon materials have been synthesized using colloidal crystals as templates. One‐dimensional carbon nanostructured materials have been fabricated using anodic aluminum oxide (AAO) as a template.     

In Situ Probing of the Particle‐Mediated Mechanism of WO3‐Networked Structures Grown inside Confined Mesoporous Channels

Nanocasting, using ordered mesoporous silica or carbon as a hard template, has enormous potential for preparing novel mesoporous materials with new structures and compositions. Although a variety of mesoporous materials have been synthesized in recent years, the growth mechanism of nanostructures in a confined space, such as mesoporous channels, is not well understood, which hampers the controlled synthesis and further application of mesoporous materials. Here, the nucleation and growth of WO₃‐networked mesostructures within an ordered mesoporous matrix, using an in situ transmission electron microscopy heating technique and in situ synchrotron small‐angle X‐ray scattering spectroscopy, are probed. It is found that the formation of WO₃ mesostructures involves a particle‐mediated transformation and coalescence mechanism. The liquid‐like particle‐mediated aggregation and mesoscale transformation process can occur in ≈10 nm confined mesoporous channels, which is completely unexpected. The detailed mechanistic study will be of great help for experimental design and to exploit a variety of mesoporous materials for diverse applications, such as catalysis, absorption, separation, energy storage, biomedicine, and nanooptics.     

Synthesis and characterization of surface-modified and organic-functionalized MCM-41 type ordered mesoporous materials

A new and efficient method for the preparation of MCM-41 type ordered mesoporous phases using phosphate as promoter under reflux conditions is reported. The various mesoporous materials studied were: silica (Si-MCM-41), alumino-silicate (Al-MCM-41), and titanium-silicate (Ti-MCM-41). Our concept of promoter-assisted synthesis of zeolites and related microporous materials was found to be applicable in the synthesis of ordered mesoporous materials as well. The addition of small catalytic quantity of phosphate ions (PO ₄ ³⁻ ), used as promoters, significantly reduced the synthesis time (by a factor of 3–4) of all these mesoporous materials. The synthesis of new MCM-41 type organic-inorganic composite materials with unique properties is also reported.     

Recent advances in functionalization of mesoporous silica

Mesoporous silica with regular geometries have been recently paid much attention owing to their scientific importance and great potentials in practical applications such as catalysis, adsorption, separation, sensing, medical usage, ecology, and nanotechnology. Especially, applications often require immobilization of the related functional groups in the mesopores. In order to achieve desire applications, modification of these mesoporous silica are indispensable. In this review, recent progresses of functionalization of mesoporous silica are comprehensively summarized. In the first parts, advances in three major methods, grafting (post-synthetic modification), co-condensation (direct synthesis), and techniques related with periodic mesoporous organosilicates, are explained. In the latter parts, new concepts for functionalization of mesoporous silica including functional template method and lizard template method are introduced. Most of the examples described here have been published in a new millennium.     

Templated,carbothermal reduction synthesis of mesoporous silicon carbide from carbon nanotube–mesoporous silica core–shell composite

Mesoporous materials are the subject of extensive interest due to their large surface area and multiscale structural order. These properties are especially relevant for applications such as catalyst supports in both chemical and electrochemical systems. The first part of this study details the synthesis of carbon nanotube–mesoporous silica core–shell composites starting with single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) through micellar self-assembly. The formation of such a composite structure was verified using scanning electron microscopy and further analysis was carried out through X-ray diffraction (XRD). The subsequent refinement of the diffraction pattern revealed the silica shell to be of the continuous cubic (Ia3d) MCM48 structure. The mesoporous silica–carbon nanotube core–shell composite was later subjected to high-temperature carbothermal reduction. Subsequent XRD analysis showed that the reduction product was mesoporous silicon carbide (SiC). Thus, this study details a novel synthesis method for mesoporous SiC, which is an attractive material for possible diverse applications such as catalyst supports, intercalation electrodes and other emerging high technology areas.