介孔氧化铝的合成及应用

通过对介孔氧化硅合成工艺的优化与修正可以用来制备介孔氧化铝分子筛。在合成介孔分子筛的前驱物中掺杂其他金属元素而将其引入骨架或将活性组分负载到介孔分子筛的基体上,可以实现对介孔分子筛表面进行表面修饰与改性,以调变分子筛表面的酸催化性能。本文综述了介孔氧化铝合成、改性研究的历史与现状,及在酸催化过程中的应用。     

掺铜的硅基介孔材料合成与应用研究进展

综述了国内外对掺杂铜的硅基介孔材料最新的改性研究进展。主要概括了采用直接合成法和合成后移植法合成铜掺杂的硅基介孔材料,较全面地比较了各合成方法之间的区别,并对材料在催化和吸附脱硫领域的应用进行探讨,同时,提出了掺铜的硅基介孔材料存在的一些问题以及对其发展前景进行展望。     

掺铜的硅基介孔材料合成与应用研究进展

综述了国内外对掺杂铜的硅基介孔材料最新的改性研究进展。主要概括了采用直接合成法和合成后移植法合成铜掺杂的硅基介孔材料,较全面地比较了各合成方法之间的区别,并对材料在催化和吸附脱硫领域的应用进行探讨,同时,提出了掺铜的硅基介孔材料存在的一些问题以及对其发展前景进行展望。     

介孔分子筛改性及在吸附脱硫中的应用

介孔分子筛由于具有较大的比表面积、孔容、孔径等优点使得其在吸附分离等领域得到了广泛的应用。本文综述了介孔分子筛改性的不同方法,包括嵌入法、负载法,以及有机-无机杂化介孔材料的制备等。对介孔分子筛在吸附脱硫方面的最新研究进展进行了总结,包括对燃料油、天然气、煤气中硫化物的吸附脱除,以及H2S、SO2等大气污染物的吸附脱除。同时对介孔分子筛的改性及发展前景进行了展望,合成新型有机-无机杂化介孔材料并将其应用于吸附等领域是未来发展的主要趋势。     

表面活性剂引导合成非硅基介孔材料的研究进展

非硅基介孔材料由于其突出的结构特性和特殊的光、电、磁性质,广泛应用于许多研究领域,使该类材料的合成逐渐成为研究者关注的焦点。本文综述了国内外近年来表面活性剂引导合成非硅基介孔材料的研究进展,阐述了离子型表面活性剂和非离子型表面活性剂作为模板剂及混合模板剂合成介孔碳、介孔金属氧化物等非硅基介孔材料的现状,归纳了合成该类介孔材料的最佳工艺条件,总结了不同模板剂引导合成的非硅基介孔材料特点,同时列表对比了不同类型表面活性剂合成该类材料的性能参数和应用领域,并对其发展进行了展望,即表面活性剂的绿色化、材料的功能化、合成过程的共模板化是未来发展的主流方向。     

硬脂酸单甘酯模板法制备介孔硅材料及功能化

以硬脂酸单甘酯非离子表面活性剂为模板剂,采用模板法自组装合成了具有介孔结构的新型纯硅基材料,并在此基础上添加镁铝改性合成了新型功能化介孔材料,采用XRD和N2物理吸附 脱附等方法进行表征,结果表明,活性物种进入了介孔硅的骨架并保持了介孔结构特征,活性物种在母体表面分散较好。以十八酸和丙三醇的酯化反应作为探针反应考察其催化性能,结果表明,功能化介孔材料有较好的酯化反应活性。     

介孔材料HMS的改性及在催化反应中的应用

六方介孔硅HMS介孔分子筛具有合成方法简单、条件温和、较大孔径、高比表面、水热稳定性高、很强的吸附和扩散能力和丰富的表面羟基等优良性能,可作为载体或催化剂应用于许多有机化学反应中,特别是应用在大分子尺寸的有机反应中。详细地综述了近10年来HMS介孔材料通过单一金属、复合金属和酸碱改性及其改性后HMS在催化反应中的应用,并对其今后的研究方向进行了展望。     

微波法合成有序介孔分子筛的研究进展

与传统的水热合成法相比,微波辐射法合成介孔分子筛材料具有反应速率快、能耗低、产物粒度均匀等优点,因而倍受关注。综述了近年来微波法应用于硅基与非硅介孔材料的合成、修饰改性等方面的研究进展。     

介孔材料化学改性研究进展

综述了介孔材料化学改性目的，改性原理以及改性方法。介孔材料的化学改性包括对材料骨架的修饰以及对孔道表面的功能化，介孔材料表面自由硅醇键、双羟基硅醇踺是化学改性的基础，利用疏水性物质改性可以提高材料的水热稳定性，引入催化活性组分可以提高催化性能，利用具有特定官能团的硅烷偶连剂改性，则能够实现特殊的目的。详述了化学改性方法，包括元素取代法、共价键移植法和有机硅烷偶连法。元素取代法是对分子筛骨架结构的修饰，共价键移植法是一种不引起孔道结构破坏且非常有效的骨架修饰方法，对介孔材料表面进行有机硅烷偶连剂法修饰改性主要有两种途径：即共沉淀法和后移植法。     

含钛介孔分子筛的合成与催化性能

论述了含钛介孔分子筛的水热合成、室温合成、微波合成和选择不同模板剂与嫁接法等合成方法及其特点。对含钛介孔分子筛的表面修饰与改性技术进行了概述。总结了含钛介孔分子筛在催化氧化、烯烃环氧化、羟基化和光催化等反应中的催化性能。指出今后的研究方向是:高水热稳定性含钛介孔分子筛的合成方法;通过对含钛介孔分子筛进行表面修饰,制备出具有独特性能的催化材料;含钛介孔分子筛在光催化及其他催化反应中的催化作用机理。     

α-Amylase immobilization capacities of mesoporous silicas with different morphologies and surface properties

α-Amylase was encapsulated in several mesoporous materials (folded sheet mesoporous silica (FSM), cubic mesoporous silica (KIT-6), and two-dimensional hexagonal mesoporous silica (SBA-15)) that differed morphologically in terms of particle shape, pore size, and pore structure. The encapsulation capacity and thermal stability of encapsulated α-amylase were examined. The amount of α-amylase encapsulated increased with increasing pore size in the following order: SBA-15 < KIT-6 < FSM. Nitrogen adsorption experiments were performed before and after α-amylase encapsulation in mesoporous silicas with pore sizes larger than the size of α-amylase, confirming that α-amylase was encapsulated in the pores. Among mesoporous silicas with similar pore sizes, FSM was found to have the highest capacity for α-amylase encapsulation both per weight and per surface area of silica. Furthermore, α-amylase encapsulated in FSM demonstrated high thermal stability at 90 °C relative to the thermal stability of free α-amylase or free α-amylase encapsulated in other mesoporous silicas. Zeta potential measurements showed that the FSM surface had an isoelectric point that was lower than that of other mesoporous silicas, and hydrophilicity measurements showed that its surface was more hydrophilic. The surface properties of FSM contributed to the high thermal stability of the α-amylase encapsulated within the pores.     

Porosity and surface properties of mesoporous silicas and their carbon replicas investigated with quasi-equlibrated thermodesorption of <Emphasis Type="Italic">n</Emphasis>-hexane and <Emphasis Type="Italic">n</Emphasis>-nonane

Adsorption of n-hexane and n-nonane on mesoporous micelle-templated silicas (SBA-15 and MLV—multilayer vesicle) and on their carbon replicas (CMK-3 and OCM—onion-like carbonaceous material) was studied by means of quasi-equilibrated thermodesorption technique, utilising a standard TPD setup with a chromatographic detector. Analysis of n-hexane adsorption isobars, determined from the thermodesorption profiles, revealed substantial heterogeneity of the adsorption sites present in the carbonaceous materials. The pore size distributions calculated from the thermodesorption profiles of n-nonane for both siliceous and carbonaceous materials were in agreement with those obtained from the low-temperature nitrogen adsorption isotherms. They confirm an uniform structure of mesopores in SBA-15, CMK-3 and OCM as well as a more complex structure of mesopores in the MLV materials.     

Macro–mesoporous silicas complex and the carbon replica

Novel macroporous silicas with ordered mesoporous wall structures (15 nm in pore size) have been synthesized by finely balancing the emulsification of the oil phase with the self-assembly of the amphiphilic block copolymers. The nanocasting method was used to produce hierarchically ordered macro–mesoporous carbon materials. These porous materials have potential applications in catalysis, sorption, separation, etc.     

Effect of porous structure on the formation of active sites in manganese hosted in ordered mesoporous silica catalysts for environmental protection

Recently ordered mesoporous silicas have been considered as suitable catalyst supports due to their high surface area, well developed porous volume and tuned size, shape and topology of mesopores. Among them SBA-15 and KIT-6 are most promising and studied materials as host matrix of metal/metal oxide nanoparticles. Both structures are characterized with cylindrical mesopores which are 2D- and 3D-packed in the SBA-15 and KIT-6 silicas, respectively. The flexibility of the oxidation state of manganese ensures high oxygen storage capacity of its oxides and provokes their wide application as catalysts in various redox processes. The aim of the current investigation is to clear the effect of pore topology in SBA-15 and KIT-6 mesoporous silicas on the state of the hosted in them manganese oxide nanoparticles. The samples were obtained by incipient wetness impregnation of silicas with manganese nitrate and conventional SiO₂ was also used as a reference support. A complex of physicochemical techniques, such as nitrogen physisorption, X-ray diffraction, UV–Vis, XPS, FTIR and temperature-programmed reduction with hydrogen was used for samples characterization. The obtained modifications were tested as potential catalysts for environmental protection via total oxidation of VOCs (ethyl acetate) or hydrogen production from methanol as clean and effective alternative fuel. It was established that the porous structure of mesoporous silica supports influences in a complex way the catalytic behaviour of their manganese modifications, which is determined by the specificity of the reaction medium.     

A green process for the synthesis of controllable mesoporous silica materials

The synthesis, characterization, and application of mesoporous silicas have attracted a lot of attention for over two decades, which stems from their fascinating structures, formation mechanisms and prospects of their applications. Various methods have been developed for the synthesis of these silicas with a tunable pore diameter and a narrow pore size distribution. In this paper, mesoporous silica materials with controllable pore diameters (3-9 nm), narrow pore size distributions, high surface area (>700 m² g⁻¹) and pore volume (>1 cm³ g⁻¹) were prepared by a green template, amphiphilic dendritic polyamidoamine. The resulting silica materials were characterized by ¹H, ¹³C NMR spectroscopy; thermogravimetic analysis; nitrogen adsorption; transmission electron microscope. It was shown that the template could be completely removed and recycled from the silica in an environmentally friendly way by means of a simple water extraction. Furthermore, it was shown that the pore diameter of these materials could be controlled by dendritic polyamidoamine with different generations and functional groups. Meanwhile, the porous framework showed strong thermal stability. Thus, a new environmentally friendly pathway for the controllable synthesis of this fascinating silicas has been proposed.     

An overview of ordered mesoporous material SBA-15: synthesis,functionalization and application in oxidation reactions

Ordered mesoporous materials are attracting wide concern because of their applications in the field of catalysis, adsorption, separations, drug delivery systems and gas sensors owing of their extremely high surface area combined with well-defined pore structures with narrow pore size distributions. Various mesoporous materials such as MCM-41, MCM-48, SBA-15 and SBA-16 have been reported in past two decades. Synthesis of mesoporous materials involves the concept of aggregation of surfactants as structure directing agents under acidic or basic conditions. The dimensions of these mesopores can be obtained by type of surfactant, auxiliary chemicals and synthesis conditions. At present, SBA-15 has attracted more attention among different mesoporous silica structures due to their desirable properties such as thick pore wall and hexagonal mesopores (4–12 nm), high surface area, ease of synthesis and functionalization and high thermal and mechanical stability. In last few years, great effort has been made on the development of various methods for the synthesis of mesoporous materials as support for oxidation reactions. The aim of this review article is to focus mainly on mesoporous SBA-15 together with its application as support for various oxidation reactions.     

电子显微镜研究分子筛的新进展

电子显微镜在沸石分子筛的研究中起着重要的作用.阐述了透射电子显微镜(TEM)和扫描电子显微镜(SEM)技术研究沸石分子筛的原理,描述了使用不同种类的电子显微镜剖析沸石分子筛的形态、尺寸、粒径分布等,并介绍了近年来电镜技术对沸石分子筛,特别是对新型功能介孔材料及手性介孔材料的研究进展.电子显微镜的发展将推动分子筛及纳米材料在选择性催化/吸附过程中的应用.     

双介孔材料的合成与应用研究进展

双介孔材料是一种同时具有小介孔和大介孔的新型多级孔材料,在吸附和催化方面具有广阔的应用前景,因此也引起许多研究者的关注。本文较全面地总结了双介孔材料的合成方法,探讨了双介孔材料作为吸附剂和催化剂载体的应用研究状况,并对今后的发展方向进行了展望:如何有效地控制两种介孔的孔结构和孔的空间分布、结构和物化性能的表征以及如何改性以扩大其应用领域尚需进一步的研究。     

软模板法合成有序介孔材料的研究进展

有序介孔材料具有高度有序的孔道结构,较高的比表面积和较多活性位,已经广泛应用于气体吸附、催化剂和功能材料等领域。本文系统评述了软模板法制备有序介孔材料的合成路线及其组装机理,并对课题组采用软模板法组装介孔氧化钛粒子的机理进行了分析。