尿素-过氧化氢混合模板法合成介孔二氧化硅

以尿素-过氧化氢为混合模板、正硅酸乙酯为硅源,在酸性条件下,通过溶胶-凝胶过程合成二氧化硅介孔材料。采用煅烧法除去模板剂,用红外光谱、XRD、N2吸附-脱附、HRTEM等分析测试手段对介孔材料的结构和形态进行了表征。结果表明:与以尿素为单一模板相比,采用混合模板剂所合成介孔材料为蠕虫状,孔径分布基本保持不变、比表面积相近(分别为445、431m2/g)、孔径(分别为7.04、8.11nm)和孔体积(分别为0.783、0.874cm3/g)明显增大。     

囊泡状介孔SiO2合成因素的研究进展

讨论了利用不同类型的表面活性剂作模板,通过硅源的水解与凝聚反应得到不同孔径的囊泡状介孔SiO2的合成过程。综述了通过改变不同反应物(模板剂、硅源、助剂)及反应条件(温度、pH值)调控囊泡形成及介孔结构转变的相关机理,并对囊泡状介孔SiO2的应用和发展前景进行了展望。     

纳米介孔CeO2的合成及表征

采用烷基聚氧乙烯基醚(Brij35)非离子型表面活性剂为模板剂,乙醇水溶液为溶剂合成了高比表面和孔径集中的介孔CeO2,考察了氨水和铈源的添加顺序、pH值等合成条件对介孔CeO2比表面、孔径分布和热稳定性的影响.运用XRD、FT-IR、DTA、N2吸附-脱附和比表面-孔径测定等手段进行了表征.结果表明,氨水加入铈源与模板剂的混合液中有利于形成介孔CeO2,且pH值在9～10范围内所得介孔CeO2材料具有较大的比表面积、孔容和较好的热稳定性.     

脲醛树脂为碳源制备介孔碳/二氧化硅及碳化温度的影响

以低聚脲醛树脂为有机碳源前驱体、正硅酸乙酯(TEOS)为无机硅源、表面活性剂F127为模板剂,采用溶剂蒸发诱导自组装(EISA)合成有序介孔碳/二氧化硅杂化材料,研究了碳化温度对于介孔碳/二氧化硅杂化材料比表面积、孔径大小及分布的影响。采用X射线衍射仪(XRD)、热失重分析仪(TGA)、透射电子显微镜(TEM)、氮气吸/脱附等对制备样品进行了表征。结果表明,随着碳化温度的升高,各样品的晶面间距缩小,孔径数值也逐渐变小。碳化温度为850℃时,所得介孔碳/二氧化硅杂化材料孔径较小且孔径尺寸分布较集中。     

模板剂对合成硅铝酸盐介孔材料的影响

为探究模板剂在合成介孔材料过程中的关键作用,本文以偏铝酸钠和水玻璃为导向剂,采用水热法在不同模板剂条件下合成硅铝酸盐介孔材料。利用X射线衍射仪(XRD),扫描电子显微镜(SEM)以及比表面积测定仪(N₂吸附/脱附)对合成样品进行表征分析,研究了模板剂种类、质量浓度及煅烧脱除模板剂温度对合成硅铝酸盐介孔材料的孔结构、形貌及性能参数的影响。研究表明,6种不同模板剂合成的硅铝酸盐介孔材料均存在明显短程有序结构,最佳模板剂为F108(PEO₁₃₃-PPO₅₀-PEO₁₃₃),质量浓度为0.04 g/mL,煅烧温度550 ℃时合成的硅铝酸盐介孔材料的结构参数达到最优。     

十八烷基三甲基溴化铵为模板合成有序介孔氧化硅及其表征

利用表面活性剂十八烷基三甲基溴化铵(STAB)为模板、正硅酸乙酯(TEOS)为硅源、盐酸为催化剂,在较低的表面活性剂浓度下(小于4%)合成了介孔氧化硅,并研究了不同的反应条件对介孔结构及有序度的影响。在热乙醇萃取或者高温煅烧除去模板剂之后,利用红外(IR)、X射线电子衍射(XRD)、高分辨透射电子显微镜(HRTEM)以及N2的吸附-脱附曲线对合成的介孔材料进行了表征。结果表明,合成的介孔氧化硅具有MCM-41型有序的孔道结构、大的孔体积(不小于1cm3/g)和BET比表面积(不小于1400m2/g),孔径均一且分布较窄。     

不同模板剂对介孔氧化铝孔径调节作用

以醇铝为原料,利用三种不同类型的模板剂对氧化铝的孔径进行调节,对各种模板剂的作用机理进行了初步探讨.研究结果表明：不同模板剂获得的介孔氧化铝的孔道结构基本一致,均为蠕虫状结构,模板剂的不同对介孔氧化铝孔径的影响较大,未加模板剂直接由溶胶-凝胶法获得的介孔氧化铝孔径分布较窄,孔径偏小;加入离子型模板剂能够形成孔径分布窄、孔径增大的介孔材料;加入非离子型模板剂则形成孔径更大,但孔径分布较宽的介孔氧化铝.     

饱和ATP为原料合成多级孔ZSM-5沸石分子筛的制备与表征

研究以饱和ATP吸附材料为合成沸石分子筛的硅源,采用双模板法,用四丙基氢氧化铵(TPAOH)为微孔模板剂和十六烷基三甲基溴化烷(CTAB)为介孔模板剂直接合成多级孔ZSM-5沸石分子筛,通过XRD、SE M、比表面积及孔径分析仪进行N_2吸附-脱附等手段对多级孔ZSM-5沸石分子筛表征测试分析。结果表明:饱和ATP吸附材料在180℃下,水热提纯12 h获得硅源,再加入TPAOH和CTAB进行初始凝胶反应,后移入水热反应釜中,控温180℃,水热晶化反应15 h,即得多级孔ZSM-5沸石分子筛。     

双功能性离子液体溶胶-凝胶法制备介孔SiO_2

首先合成了一种新型双功能性离子液体1-甲基-3-(3'-磺酸丙基)咪唑十二烷基磺酸盐([PMIM(SO3H)][C12SO3]),并采用FT-IR、1H NMR和13C NMR对其结构进行了表征;进一步以该离子液体为模板剂和酸源,以正硅酸乙酯(TEOS)为硅源,通过溶胶-凝胶法制备出介孔SiO2,利用TGA和FT-IR研究了介孔材料的形成过程,采用SAXRD、SEM、TEM和氮气等温吸附-脱附等手段对介孔材料的结构形貌进行了表征,并研究了其对Pb2+的吸附性能。结果显示,以[PMIM(SO3H)][C12SO3]为模板剂和酸源制备的介孔SiO2其比表面积、孔容、平均孔径大小分别为1 010m2/g、0.95 cm3/g、3.25 nm,其对重金属Pb2+有很好的吸附性能。     

1,3,5-三甲苯扩孔改性硼掺杂有序介孔炭

以F108为模板剂,1,3,5-三甲苯(TMB)为有机扩孔剂,采用溶剂挥发诱导自组装的方法成功制备出了具有较大孔径、比表面积和有序性高的硼掺杂有序介孔炭。探究了扩孔剂用量对硼掺杂介孔炭结构的影响,并对其电化学性能和扩孔机理进行了分析。结果表明,当扩孔剂与模板剂的用量比为1.5时,所得的介孔炭TMB-1.5的孔径最大(4.2nm),比表面积最高(666m~2/g)。相对于未扩孔改性的介孔炭,孔径和比表面积分别提高了5%和10%。扩孔改性后的硼掺杂介孔炭具有良好的电化学性能,在0.2A/g电流密度下的比电容高达235F/g。     

The size-controllable synthesis of nanometer-sized mesoporous silica in extremely dilute surfactant solution

10–60 nm-sized mesoporous silica particles with ordered or worm-like pore structures were controllably synthesized in extremely dilute surfactant solution, and the lowest concentrations of TEOS and CTAB were 12.45 mM, 1.52 mM, respectively. The synthesis of nanometer-sized Al-incorporated mesoporous silica particles (Al-MS) was also performed under the similar conditions. Compared to the mesoporous silica without doping of aluminum, those Al-incorporated silica particles have a certain textural mesoporosity. The results indicate that the size and pore structure of mesoporous silica can be adjusted by changing the concentration of reactants. The mesoporous silica nanoparticles, including Al-MS, were characterized by transmission electron microscopy (TEM), small-angle X-ray diffraction (SAXRD), as well as nitrogen adsorption/desorption techniques. It was suggested that the formation of the mesoporous silica nanoparticles could be attributed to the deposition of self-assembled silicate micelles.     

Observation of quantum confinement effect on ZnO embedded mesoporous silica

Nonionic surfactant as liquid organic template and tetraethoxysilane as silica precursor were used for the synthesis of mesoporous silica with ordered arrangement of nanopores (diameters are about 1-6 nm). The synthesized mesoporous silica was used as the template for the synthesis of ZnO nanoparticles using zinc acetylacetonate as ZnO precursor. The as synthesized ZnO incorporated in the mesoporous silica nanocomposite were analyzed using X-ray diffraction, TEM and Photoluminescent spectrum. ZnO introduction has no extensive influence on the mesoporous structure of silica. Quantum confinement effects are observed in the case of ZnO nanoparticles embedded in mesoporous silica. The particle size of ZnO is about 3.2 nm. The band gap is broadening to 3.47 eV.     

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.     

Hollow mesoporous aluminosilicate spheres with acidic shell

Hollow mesoporous aluminosilicate spheres (HMAS) with middle strong acidity have been successfully synthesized by simply hydrothermally treating mesoporous silica spheres (MSS) in zeolite precursor solution. Based on a set of time-dependent experiments, it was found that the hollowing process was associated with a progressive mass redistribution and changes of pores structures. The surfactant cetyltrimethylammonium bromide (CTAB) located in the pores of MSS protected the mesoporous silica spheres from dissolving into strongly basic zeolite precursor solution and acted as the template for mesoporous shell. Under the templating function of CTAB, primary zeolite units were introduced into the mesopore walls of HMAS. The acidity of the resultant samples HMAS was measured by NH₃-TPD techniques. Catalytic tests showed that the HMAS catalysts exhibited high catalytic activity compared with the MSS and Hβ zeolite for catalytic cracking of 1,3,5-triisopropylbenzene.     

同步合成模板炭化法制备双电层电容器电极用中孔炭材料的研究

以正硅酸乙酯为模板硅源，间苯二酚—甲醛凝胶为炭前驱体，采用同步合成模板炭化(SSTCM)法制备了具有可控结构的中孔炭材料。炭材料的比表面积可达1500m^2/g，平均孔径在3nm～10nm之间。经过酸催化水解预处理的二氧化硅模板前驱体溶液与间苯二酚—甲醛溶液混合，碱性条件下使两者的溶胶凝胶反应同步发生，得到有机，无机凝胶混合物。再经炭化、HF去模，制得SSTCM炭材料。N2等温吸脱附研究表明，与炭前驱体聚合物同步合成的结构可调的二氧化硅模板，导致了SSTCM炭材料可控中孔结构的形成。循环伏安研究表明，采用这种同步合成模板炭化法制备的SSTCM炭材料质量比容量达270F／g，炭材料具有的典型中孔结构使其可能成为一种理想的双电层电容器电极材料。     

Selective adsorption and release of cationic organic dye molecules on mesoporous borosilicates

Mesoporous materials can play a pivotal role as a host material for delivery application to a specific part of a system. In this work we explore the selective adsorption and release of cationic organic dye molecules such as safranine T (ST) and malachite green (MG) on mesoporous borosilicate materials. The mesoporous silica SBA-15 and borosilicate materials (MBS) were prepared using non-ionic surfactant Pluronic P123 as template via evaporation induced self-assembly (EISA) method. After template removal the materials show high surface areas and in some cases ordered mesopores of dimensions ca. 6–7 nm. High surface area, mesoporosity and the presence of heteroatom (boron) help this mesoporous borosilicate material to adsorb high amount of cationic dye molecules at its surface from the respective aqueous solutions. Furthermore, the mesoporous borosilicate samples containing higher percentage adsorbed dyes show excellent release of ST or MG dye in simulated body fluid (SBF) solution at physiological pH = 7.4 and temperature 310 K. The adsorption and release efficiency of mesoporous borosilicate samples are compared with reference boron-free mesoporous pure silica material to understand the nature of adsorbate–adsorbent interaction at the surfaces.     

Facile synthesis of ordered mesoporous silica with high γ-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> loading via sol-gel process

A series of ordered mesoporous silica loaded with iron oxide was synthesized by facile one-step sol-gel route using Pluronic P123 as the template, tetraethylorthosilicate as the silica source, and hydrated iron nitrite as the precursor under acid conditions. The as-synthesized materials with Fe/Si molar ratio ranging from 0.1 to 0.8 were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), and N₂ adsorption porosimetry. All samples possess ordered hexagonal mesoporous structure similar to SBA-15, with a high surface area, large pore volume, and uniform pore size. Although higher iron content causes a distortion of hexagonal ordering structure to some extent, the materials still maintain the ordered mesopore structure even with Fe/Si molar ratio as high as 0.8. Pore structure and TEM data suggest that iron oxide nanoparticles are buried within the silica wall, and increasing the iron oxide loading has little effects on the pore structure of the mesoporous silica. VSM results show as-synthesized samples exhibit superparamagnetic behavior.     

Pore structure control of mesoporous carbon as supercapacitor material

The pore structure and electrochemical performances of mesoporous carbons prepared by silica sol template method as electrode material for supercapacitor were investigated in this work. The pore size distribution of the mesoporous carbons changes from unimodal to bimodal and the mean pore size increases with the increase of silica sol/glucose ratio. The specific capacitance of the mesoporous carbons also increases with the increase of silica sol/glucose ratio. A novel technique named as template–chemical activation method, combining both template and chemical activation methods, is proposed, which can effectively control the pore structure, improving the electrochemical properties of the mesoporous carbon with improved porosity especially microporosity.     

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.