Synthesis of carboxyl-modified rod-like SBA-15 by rapid co-condensation

Carboxyl-modified SBA-15 rod-like mesoporous materials have been synthesized by a facile rapid co-condensation of tetraethylorthosilicate (TEOS) and 2-cyanoethyltriethoxysilane (CTES), followed by hydrolysis of cyanide groups in sulfuric acid. The concentration of carboxylic groups was varied by changing the silica source ratio of CTES/TEOS from 0.05 to 0.3. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the uniform ordered mesoporous structure and rod-like morphology of SBA-15 have been preserved even at the high concentration of carboxylic groups employed. Characterization by Fourier transformed infrared spectroscopy (FTIR), solid-state NMR investigation indicated that carboxylic groups have been successfully grafted onto the surface of SBA-15 through siloxane bonds [(O(3))SiCH(2)CH(2)COOH. The negative charges of the modified SBA-15 materials were enhanced by the presence of the carboxylic groups on the surface. The capacity of lysozyme adsorption of the modified SBA-15 materials were found to be significantly improved as compared with pure silica SBA-15. The maximum amount of lysozyme adsorption on carboxyl-modified was increased with the pH of solution increased from 5.5 to 9.0.     

六方平板状氨基-甲基双官能化SBA-15的合成及对胆红素的吸附

以氨丙基甲基二乙氧基硅烷和正硅酸乙酯为硅源,三嵌段共聚物P123为模板剂,无机盐KCl为助剂,酸性条件下一步法合成了氨基-甲基双官能化SBA-15（AMS）. XRD,FTIR,BET,29Si MAS NMR,SEM及HRTEM等表征结果表明：无机盐不仅提高了AMS材料的介孔有序度,而且控制样品形貌从六方平板状向纤维状转变. 胆红素吸附实验表明：六方平板状AMS比纤维状AMS和纯SBA-15具有更快的吸附速率和更大的吸附容量,这可能是六方平板状形貌易于胆红素扩散以及双官能基团（甲基,氨基）增加了对胆红素吸附作用力的结果.     

利用嵌段共聚物及无机盐合成高质量的立方相、大孔径介孔氧化硅球

使用非离子型嵌段高分子表面活性剂为模板剂,在无机盐的作用下,合成了直 径在2～4 mm、高度有序、立方相的介孔氧化硅SBA-16球。利用无机盐来调变无机 /有机物种之间的作用力和自组装能力,不仅在介观尺寸上提高了所合成介孔材料 的有序程度,而且在宏观上控制了介孔材料的形貌。经焙烧后的SBA-16球材料比表 面积为750 m~2/g,孔容为0.52 cm~3/g,孔径为7.8 nm。具有大孔径的SBA-16球材 料可以更方便地应用于大分子吸附和分离等领域。     

Synthesis and characterization of periodic mesoporous organosilicas from bridged organosilanes in the presence of mixed salts

A simple but effective synthetic pathway to periodic mesoporous organosilicas (PMOs) has been put forward in this article. The novelty of the present preparative route lies in that, for specific examples, highly ordered ethane- and benzenesilica PMOs can be facilely prepared in the presence of an inorganic salt pair within a wide compositional range, where no addition of mineral acids was necessary. Most of interest is that crystal-like pore walls were observed for the large-pore benzenesilica PMO promoted by this novel system, which has rarely been reported for copolymer-assembled organosilicas, even though the degree of molecular order is not as perfect as those benzenesilicas prepared under basic conditions utilizing cationic surfactants as template. Characterization results based on a series of techniques indicated that both inorganic salts are important for the assembly of ordered mesostructures under the present system, and a plausible formation mechanism deduced from the “salt-assisted” concept as previously reported for mesoporous nonsiliceous materials was discussed.     

Periodic Mesoporous Organosilicas: A Type of Hybrid Support for Water‐Mediated Reactions

Hybrid mesoporous periodic organosilicas (Ph‐PMOs) with phenylene moieties embedded inside the silica matrix were used as a heterogeneous catalyst for the Ullmann coupling reaction in water. XRD, N₂ sorption, TEM, and solid‐state NMR spectroscopy reveal that mesoporous Ph‐PMO supports and Pd/Ph‐PMO catalysts have highly ordered 2D hexagonal mesostructures and covalently bonded organic–inorganic (all Si atoms bonded with carbon) hybrid frameworks. In the Ullmann coupling reaction of iodobenzene in water, the yield of biphenyl was 94 %, 34 %, 74 % and for palladium‐supported Ph‐PMO, pure silica (MCM‐41), and phenyl‐group‐modified Ph‐MCM‐41 catalysts, respectively. The selectivity toward biphenyl reached 91 % for the coupling of boromobenzene on the Pd/Ph‐PMO catalyst. This value is much higher than that for Pd/Ph‐MCM‐41 (19 %) and Pd/MCM‐41 (0 %), although the conversion of bromobenzene for these two catalysts is similar to that for Pd/Ph‐PMO. The large difference in selectivity can be attributed to surface hydrophobicity, which was evaluated by the adsorption isotherms of water and toluene. Ph‐PMO has the most hydrophobic surface, and in turn selectively adsorbs the reactant haloaryls from aqueous solution. Water transfer inside the mesochannels is thus restricted, and the coupling reaction of bromobenzene is improved.     

Synthesis of large-pore methylene-bridged periodic mesoporous organosilicas and its implications

In this article, we report the synthesis of methylene-bridged periodic mesoporous organosilicas (PMOs) of the SBA-15 type. The materials were characterized by SAXS, BET, NMR, FESEM, and TEM. It was found that the synthesis of methylene-bridged SBA-15 PMOs requires more rigorous conditions than that of SBA-15 PMOs bearing organic bridges other than methylene. A mild acidic environment, which slows down the hydrolysis and condensation rates of the precursor, with the assistance of a salt, which enhances precursor-template interaction, should be used to synthesize high-quality large-pore methylene-bridged PMOs. We attributed this to the fast hydrolysis and condensation rates and the rigid backbone of precursor 1,2-bis(triethoxysilyl)methylene. By examining and comparing the synthesis of three large-pore PMOs with different bridges, we concluded that the inductive, bridging, and conformation effects of the organic bridging group play an important role in the synthesis of large-pore PMO materials.     

Salt-induced formation of uniform fiberlike SBA-15 mesoporous silica particles and application to toluene adsorption

Long, homogeneous fiberlike SBA-15 mesoporous silica particles are prepared by fine adjustment of three reaction conditions--stirring temperature, stirring time, and amount of inorganic salt added--using Pluronic P123 and TEOS under acidic conditions. The addition of NaCl along with a short stirring time played an important role in controlling the morphology and pore characteristics. Dynamic adsorption performance for gaseous toluene was systematically evaluated using four types of materials with different morphologies and pore characteristics synthesized with the addition of a different amount of NaCl. Breakthrough curves showed that the longer the fiberlike structure, the longer the breakthrough time. Furthermore, it was found from the breakthrough times and the total amounts adsorbed that long particles with high microporosity offer effective adsorption performance and should be useful in applications such as toluene adsorption.     

Periodic Mesoporous Organosilica Nanoparticles with Controlled Morphologies and High Drug/Dye Loadings for Multicargo Delivery in Cancer Cells

Despite the worldwide interest generated by periodic mesoporous organosilica (PMO) bulk materials, the design of PMO nanomaterials with controlled morphology remains largely unexplored and their properties unknown. In this work, we describe the first study of PMO nanoparticles (NPs) based on meta‐phenylene bridges, and we conducted a comparative structure–property relationship investigation with para‐phenylene‐bridged PMO NPs. Our findings indicate that the change of the isomer drastically affects the structure, morphology, size, porosity and thermal stability of PMO materials. We observed a much higher porosity and thermal stability of the para‐based PMO which was likely due to a higher molecular periodicity. Additionally, the para isomer could generate multipodal NPs at very low stirring speed and upon this discovery we designed a phenylene–ethylene bridged PMO with a controlled Janus morphology. Unprecedentedly high payloads could be obtained from 40 to 110 wt % regardless of the organic bridge of PMOs. Finally, we demonstrate for the first time the co‐delivery of two cargos by PMO NPs. Importantly, the cargo stability in PMOs did not require the capping of the pores, unlike pure silica, and the delivery could be autonomously triggered in cancer cells by acidic pH with nearly 70 % cell killing.     

A two-step route to synthesis of small-pored and thick-walled SBA-16-type mesoporous silica under mildly acidic conditions

Highly ordered SBA-16-type mesoporous silica materials were synthesized by using poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) triblock copolymer (EO(132)-PO(50)-EO(132), Pluronic F108) as template through a two-step pathway under mildly acidic conditions (pH 2.15-4.50). The highly ordered cage-like mesoporosity of the prepared SBA-16-type mesoporous silica materials having Im3m cubic mesostructure was proved by the well-defined X-ray diffraction patterns combined with transmission electron microscopy. Scanning electron microscopy shows a variation from the spherical agglomerations to the randomly shaped ones with an increase of pH value. The nitrogen adsorption-desorption analysis reveals that the prepared SBA-16-type mesoporous silica materials have a uniform small-sized pore diameter (3.37-4.24 nm) and very thick pore wall (8.84-10.2 nm). These features may make the SBA-16-type mesoporous silica materials synthesized in this study favor the incorporation of catalytically active heteroatoms in silica frameworks, and the functionalization of organic groups for applications in catalysis, sensor and separation. The two-step synthetic method under the mildly acidic conditions can also be extended to the production in the industrial scale as an environmentally friendly way.     

孔壁富含微孔有序介孔材料的设计合成及表征

通过调节水热处理溶液的酸度和温度,进而调控材料孔壁上硅羟基与模板剂的相互作用以及模板剂亲水嵌段嵌入到孔壁内的量,制备出了墙壁富含微孔的有序介孔材料SBA-15.氮气吸附测试表明,当水热处理溶液的pH值和温度分别为2.2和100℃时,经300℃焙烧脱除模板剂后的样品具有较高的微孔含量,其微孔体积为0.176cm3/g,占总孔体积的21.6%.     

Three‐Dimensional Ultralarge‐Pore Ia3d Mesoporous Silica with Various Pore Diameters and Their Application in Biomolecule Immobilization

Highly ordered mesoporous three‐dimensional Ia3d silica (KIT‐6) with different pore diameters has been synthesized by using pluronic P123 as surfactant template and n‐butanol as cosolvent at different synthesis temperatures in a highly acidic medium. The materials were characterized by XRD and N₂ adsorption. The synthesis temperature plays a significant role in controlling the pore diameter, surface area, and pore volume of the materials. The material prepared at 150 °C, KIT‐6‐150, has a large pore diameter (11.3 nm) and a high specific pore volume (1.53 cm³ g^?1). We also demonstrate immobilization of lysozyme, which is a stable and hard protein, on KIT‐6 materials with different pore diameters. The amount of lysozyme adsorbed on large‐pore KIT‐6 is extremely large (57.2 μmol g^?1) and is much higher than that observed for mesoporous silicas MCM‐41, SBA‐15, and KIT‐5, mesoporous carbons, and carbon nanocages. The effect of various parameters such as buffer concentration, adsorption temperature, concentration of the lysozyme, and the textural parameter of the adsorbent on the lysozyme adsorption capacity of KIT‐6 was studied. The amount adsorbed mainly depends on solution pH, ionic strength, adsorption temperature, and pore volume and pore diameter of the adsorbent. The mechanism of adsorption on KIT‐6 under different adsorption conditions is discussed. In addition, the structural stability of lysozyme molecules and the KIT‐6 adsorbent before and after adsorption were investigated by XRD, nitrogen adsorption, and FTIR spectroscopy.     

NPE在有序介孔炭上的吸附行为研究

采用有序介孔硅为硬模板制备了具有不同孔径的有序介孔炭(OMCs). 氮气吸附测试表明, 有序介孔炭具有丰富的介孔表面和集中的介孔分布. 以壬基酚聚氧乙烯醚(NPE)为探针分子, 研究了大分子酚类在有序介孔炭上的吸附行为. 吸附研究表明, NPE在有序介孔炭上的吸附满足Langmuir吸附模型. 孔结构分析表明, 大于1.5 nm的孔的表面积是决定NPE吸附量的关键因素, 而有序介孔炭的最可几孔径决定吸附速率的大小. 与吸附量相比, 吸附速率更容易受环境温度的影响. 动力学研究表明, NPE在有序介孔炭上的吸附满足准二级动力学方程.     

SBA-15负载CeO2纳米晶的溶胶-凝胶一步合成

以P123为模板剂, 正硅酸乙酯和硝酸铈为前驱体, 通过溶胶-凝胶路线在酸性条件下合成了SBA-15负载氧化铈(CeO2与SiO2质量比为28.7%)有序介孔材料. 采用热重/差热分析(TGA/DTA)、X射线衍射(XRD)、透射电镜(TEM)和氮气吸附等手段对所合成材料进行了表征. 结果表明, 合成的材料具有类似于SBA-15的结构, 孔径、孔容和比表面积分别为38.7 Å, 0.46 cm3/g和570 m2/g. X射线衍射(XRD)、透射电镜(TEM)、X射线能谱(EDS)和选区电子衍射花样联合表征证实了铈物种以高分散的CeO2纳米晶的形式分布在介孔基体中.     

孔壁部分有序化的介孔二氧化硅材料的合成与表征

采用一种“改进的二次晶化”的方法处理介孔二氧化硅SBA-15. 用X射线衍射(XRD)、 透射电镜(TEM)、 电子衍射(ED)、 红外光谱(FTIR)以及固体核磁共振(NMR)等多种技术对样品进行了表征.　结果表明， 在所得样品的孔壁中, 原子的排列方式与普通介孔二氧化硅材料的孔壁不同， 显示一定程度的有序性. 同时, 高度有序的介孔结构得到很好的保持, 且样品的水热稳定性大幅度提高.     

Basic sites on periodic mesoporous organosilicas investigated by XPS and in situ FTIR of adsorbed pyrrole

Oxygen sites in ethane-bridged and phenylene-bridged PMOs prepared using neutral templates in acidic conditions are characterized by means of XPS and FTIR spectroscopy of adsorbed pyrrole. Their electron donor ability is observed to be stronger than that of oxygens in pure amorphous silica of MCM-41 type and comparable to that reported for oxygen atoms in some alkali metal exchange zeolites. For pyrrole adsorbed on PMOs double interactions most probably occur, involving both silanols and electron donor sites at the surface. In the case of phenylene-bridged PMO preferential electron donor sites for interaction with pyrrole N-H group are aromatic rings rather than oxygens, as previously observed for adsorbed iodine.     

有序介孔炭的合成及液相有机大分子吸附性能研究

分别采用有序介孔氧化硅SBA-15和NaY分子筛为硬模板合成了系列有序介孔炭OMC和微孔炭CFY. N₂静态吸附测试表明, 所合成的介孔炭具有丰富的介孔结构和集中的介孔分布. 以亚甲基蓝为探针分子, 研究其在有序介孔炭OMC和微孔炭CFY上的吸附行为. 研究结果表明, 有序介孔炭中大于3.5 nm的大介孔孔容是决定亚甲基蓝吸附容量和吸附速率的关键因素. 吸附动力学理论研究表明, 准二级动力学方程可以很好地描述亚甲基蓝分子在介孔炭上吸附动力学行为.     

富含羧基的球形介孔分子筛SBA-15的合成及药物释放性能

本文采用原位合成法合成了富含羧基的SBA-15球形介孔分子筛. 研究了修饰剂（三烷氧基氰乙基硅烷 CTES）的用量对介孔分子筛SBA-15形貌、孔径及BET比表面积的影响. 用粉末X射线衍射(XRD)、扫描电镜(SEM)、红外（IR）和氮气吸附/脱附对样品进行了详细的表征. 该材料展示了尺寸在0.5-1 μm规则的球形形貌、有序的二维六方相介孔结构、较大的比表面积和孔容、并且随着修饰剂用量的增加, SBA-15的孔径变小, 比表面积下降. 药物组装及缓释性能测试表明, 该材料具有较好的药物组装及缓释释放性能. 该材料在催化、药物载体和色谱分析填料等领域将具有潜在的应用.     

Synthesis and characterization of nanocast silica NCS-1 with CMK-3 as a template

Nanocast silica (NCS-1) was synthesized by a casting process by employing the mesoporous carbon CMK-3 (the replica of SBA-15) as a template, tetraethoxysilane (TEOS) as the silica source, and hydrochloric acid (HCl) as the catalyst. The ordered carbon template was removed by employing different methods, such as calcination, thermal treatment followed by calcination, and controlled combustion. According to XRD and TEM characterization, NCS-1 exhibits an ordered structure with hexagonal symmetry and retains the morphology of the original SBA-15 used for the synthesis of CMK-3 over two replication steps on the nanometer scale. This demonstrates the well-connected porosity in CMK-3 type carbon, which can be used as a mold to synthesize mesostructured materials. The nitrogen adsorption isotherms generally show type IV shape, indicating mesoporous characteristics. The structure of NCS-1 is strongly influenced by variables of the nanocasting process, such as the loading amount of silica, hydrolysis temperature, and carbon removal methods. The surface area, pore size, and pore volume of NCS-1 can be tuned to a certain range by varying these parameters.     

Synthesis of porphyrin-bridged periodic mesoporous organosilica and their catalytic applications

Periodic mesoporous organosilicas (PMOs) were prepared by cooperative assembly with corresponding organosilane precursors in the presence of surfactants. Recently, approaches for the preparation of a new class of porphrin-bridged PMOs have been developed. Porphyrin-bridged PMOs were synthesized by direct co-condensation using a thermal sol–gel method or a rapid microwave-assisted method with tetrakis(carboxyphenyl)porphyrin(TCPP)-silsesquioxane (TCPPS) and various silica sources in the presence of templates. These porphyrin PMO exhibited high catalytic activities and selectivity and could be used repeatedly in many kinds of applications owing to easy accessibility, rapid diffusion, and favorable mass transfer for substrates into and out of the mesopores. In addition, the TCPPS incorporated into the PMO walls could effectively defend damage of the ordered structure and also inhibit the leaching of active sites. The current review deals with recent development in the synthesis, characterization, and applications such as hydrogenation, photocatalysis, chiral catalysis, and Baeyer–Villiger oxidation of each of these types of porphyrin-bridged periodic mesoporous silica materials.     

Highly Carboxylic‐Acid‐Functionalized Ethane‐Bridged Periodic Mesoporous Organosilicas: Synthesis,Characterization, and Adsorption Properties

Functionalization of periodic mesoporous organosilicas (PMOs) with high loadings of pendant organic groups to form bifunctional PMOs with ordered mesostructures remains a challenging objective. Herein, we report that well‐ordered ethane‐bridged PMOs functionalized with exceptionally high loadings of pendant carboxylic acid groups (up to 80 mol % based on silica) were synthesized by the co‐condensation of 1,4‐bis(trimethoxysilyl)ethane (BTME) and carboxyethylsilanetriol sodium salt (CES) with Pluronic P123 as the template and KCl as an additive under acidic conditions. The bifunctional materials were characterized by using a variety of techniques, including powder X‐ray diffraction, nitrogen‐adsorption/desorption, TEM, and solid‐state ¹³C and ²⁹Si NMR spectroscopy. Zeta‐potential measurements showed that the surface negative charges increased with increasing the CES content. This property makes them potential candidates for applications in drug adsorption. The excellent adsorption capacity of these bifunctional PMOs towards an anticancer drug (doxorubicin) was also demonstrated.