晶态介孔金属氧化物的合成研究进展

晶态介孔金属氧化物与相应的无定形材料相比具有更加优异的催化、光学、电学、磁学和力学等性能,具有较宽的应用范围,是近年来介孔材料合成的热点。本文主要对晶态介孔金属氧化物的制备方法,包括非晶晶化法、蒸发诱导自组装法和硬模板法进行了介绍,并对这些方法的优缺点进行了比较。     

木质素基介孔碳材料的制备及应用进展

木质素是自然界中唯一可提供再生性芳香基化合物的非石油类资源,酚羟基的可替代性、低成本及其高含碳量使其成为合成可持续介孔碳的优选前体。本文分别介绍了采用硬模板法、软模板法、双模板法、活化法、水热法以及溶胶-凝胶法制备木质素基介孔碳材料的最新研究进展。分析对比了采用不同方法制备的介孔碳材料所具有的孔道结构和形貌特点,并详细说明了其在吸附、催化、药物缓释和超级电容器等主要方面的应用。最后根据木质素基介孔碳材料在制备及应用过程中所面临的困境,提出发展一种简单、绿色、低成本的合成方法用以制备新型介孔结构的高性能复合型木质素基介孔碳材料将成为今后主要的研究方向。     

介孔羟基磷灰石的硬/软模板合成及自组装

本文探讨了采用硬、软模板以及单分散HAP纳米晶组装制备介孔HAP的工艺、方法及材料的表征与分析方法;展望了通过优化合成工艺,制备孔径在数纳米至数十纳米范围可调,孔径分布窄、周期性好的三维孔道HAP介孔材料的最佳策略及其潜在的应用.     

有序介孔碳材料的模板化构筑及水处理应用研究

介孔碳材料是指孔径介于2 nm-50 nm的一类多孔碳材料。有序介孔碳材料，具有比表面积高、孔道结构规则有序、孔径分布狭窄、孔径大小可调控、表面易于修饰等结构特点和高机械强度、强吸附能力、化学惰性等性能特点，在诸多领域得到了广泛应用，特别是其作为新型吸附剂在水处理领域具有广阔的发展前景。有序介孔炭材料的制备方法主要有硬模板法和软模板法。模板和碳源的选择是控制有序介孔碳材料结构和性能的关键因素。本文从有序介孔硅、天然矿物、MOFs材料、嵌段共聚物等不同模板的角度对有序介孔碳、多级有序微/介孔碳、多级有序大/介孔碳的制备方法进行综述，并对有序介孔碳材料在水处理领域的应用进行简单介绍。     

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。     

无机介孔材料的合成研究新进展

综述了无机介孔材料的制备方法,包括软模板法和硬模板法,并对硬模板法包含的液相浸渍法、化学气相沉积法(CVD)、固相研磨法、超声波辅助法进行了详细阐述,展望了硬模板法合成介孔材料的前景。     

介孔材料的制备与应用进展

综述了模板法、水热法、溶胶-凝胶法、溶剂热法、超声化学法及反胶束法等制备介孔材料的方法,其中模板法介绍了阳离子表面活性剂、阴离子表面活性剂、非离子表面活性剂、混合表面活性剂以及非表面活性剂等作为模板剂在介孔材料制备中的应用.评述了介孔材料的几种典型形貌,并对介孔材料在催化、吸附分离、传感器电极材料的制备以及酶的固定与分离等领域的应用进行了简要介绍.     

生物质基介孔碳材料制备的研究进展

分别介绍了近年来采用硬模板法、软模板法、溶胶-凝胶法和水热法等主要方法制备生物质基介孔碳材料及其在吸附、催化、药物控释和超级电容器等领域应用的研究进展。最后对生物质基介孔碳材料今后开展进一步研究的方向进行了展望。     

有序介孔碳材料的研究进展

一般制备有序介孔碳材料的方法为模板法,近年来有关模板法的研究取得了很大的发展,不再局限于以往复杂的硬模板法,基于有机-有机自组装机制的软模板法逐渐兴起并得到了广泛的研究。为提高有序介孔碳材料性能,也在探索更高效的材料改性方法。同时,随着该种材料性能的提高,其在电能源领域的应用也越来越重要。     

介孔材料的制备及应用

介孔材料的许多优异性能使其成为材料研究的热点。本文综述了近年来介孔材料的制备方法，包括模板法、溶胶一凝胶法、水热法、沉淀法、硬模板法等；同时简要介绍了其在吸附、催化、电极、电客、信息储运和医药基因工程方面的应用。     

高岭土原位合成Y型沸石过程中的吸附研究

采用N2静态吸附法和IR光谱法研究了高岭土原位晶化合成Y型沸石过程中的孔结构和沸石的形成过程。结果显示，在原位晶化过程中，从天然高岭土到晶化产物，孔结构发生了很大的变化，从大孔到中孔发达的过程，焙烧微球在碱溶液的作用下，形成了发达的孔道结构，进而在孔道的可接近表面上均匀地生长出了Y型沸石；原位晶化过程是焙烧微球在液相组分中先转变为硅铝酸钠凝胶，随后硅铝酸钠凝胶逐步地转变为Y型沸石。     

Highly ordered mesoporous CoFe<Subscript>2</Subscript>O<Subscript>4</Subscript> and CuFe<Subscript>2</Subscript>O<Subscript>4</Subscript> with crystalline walls

The highly ordered mesoporous CoFe₂O₄ and CuFe₂O₄ with crystalline walls can be synthesized by hard template with using mesoporous silica SBA-15 as hard template and using ferric nitrate, cobalt nitrate, and copper nitrate as metal precursors. These new mesoporous materials above have high surface areas, narrow pore size distribution, and large pore volumes, which are believed to be valuable for the potential application in the field of sensors, catalysis, message recording, magnetics, and biology. This work provides a method to fabricate the highly ordered mesoporous materials composed of multi-metal oxides with crystalline walls. The development of such versatile approach is of great significance in practical application. It can be envisaged that this established method is significantly expandable to the controlled synthesis of the mesoporous functional materials with diverse compositions.     

Synthesis of highly stabilized mesoporous molecular sieves using natural clay as raw material

Mesoporous molecular sieves were hydrothermally synthesized from natural clay and sodium silicate by using cetyl trimethyl ammonium bromide (CTAB) as a template. The samples were characterized by means of XRD, TEM, TPR, FT-IR and N₂ physical adsorption. The results show that well-ordered and highly stabilized mesoporous molecular sieves were obtained by adjusting the proportion of raw materials. The pore structure of the as prepared mesoporous molecular sieves was not damaged after calcination at 850 °C for 3 h or hydrothermal treatment at 100 °C for 10 days. The mesoporous ordering became better after hydrothermal treatment, but the pore shrank and the surface area decreased after thermal treatment. The stability of the as prepared mesoporous molecular sieves depends on the stability of the clay present in mesoporous pore walls. The presence of clay in the walls can be certified by the regular pore channel images as determined by TEM and XRD analyses.     

The self-assembly of gold nanoparticles in large-pore ordered mesoporous carbons

Simple encapsulation of 3 nm gold nanoparticles in ordered mesoporous carbon with large pores of 17 nm and thick pore walls of 16 nm was achieved by a metal-ligand coordination assisted-self-assembly approach.Polystyrene-block-polyethylene-oxide (PS-b-PEO) diblock copolymer with a large molecular weight of the PS chain and mercaptopropyltrimethoxysilane were used as the template and the metal ligand,respectively.Small-angle X-ray scattering,X-ray diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy showed that monodispersed aggregation-free gold nanoparticles approximately 3 nm in size were partially embedded in the large open pore structure of the ordered mesoporous carbon.The strong coordination between the gold species and the mercapto groups and the thick porous walls increased the dispersion of the gold nanoparticles and essentially inhibited particle aggregation at 600 ℃.The gold nanoparticles in the ordered mesoporous carbon are active and stable in the reduction of nitroarenes involving bulky molecules using sodium borohydride as a reducing agent under ambient conditions (30 ℃) in water.The large interconnected pore structure facilitates the mass transfer of bulky molecules.     

Metal Triflates Incorporated in Mesoporous Catalysts for Green Synthesis of Fine Chemicals

Strong Lewis acid SnTf-MCM-41 and SnTf-UVM-7 catalysts with unimodal and bimodal pore systems were prepared in a two-step synthesis in which the triflic acid (Tf) was incorporated into previously synthesized mesoporous tin-containing silicas. The Sn incorporation inside the pore walls was carried out through the Atrane method. The SnTf-UVM-7 catalysts were prepared by aggregating nanometric mesoporous particles defining a hierarchic textural-type additional pore system. Catalysts with different Si/Sn ratios in the range 21.8–50.8 for SnTf-MCM-41 and 18.4 for SnTf-UVM-7 were found to be efficient catalysts for the acylation of aromatics and heteroaromatics. Under microwave irradiation the reaction was possible even with acetic acid. The selectivity to the desired product (o-hydroxyacetophenone for phenol) or the unfavored three-substituted five ring heterocycles was dramatically increased under these conditions. The process is green, environmentally safe, and heterogeneous.     

新型磺酸基功能化的介孔MCM-41分子筛的合成及其性能研究

利用糠醇的聚合和碳化对介孔分子筛Al-MCM-41进行表面处理后,直接加浓硫酸磺化制备了一系列新型的磺酸基功能化的介孔MCM-41分子筛催化剂,并用氮气吸附-脱附(BET)、X-射线粉末衍射(XRD)、傅里叶变换红外光谱(FTIR)和吡啶-程序升温脱附(吡啶-TPD)等方法对其进行了结构表征,以乙酸与乙醇的酯化反应为模...     

Phase transition of mesoporous SiO<Subscript>2</Subscript> impregnated with an organic templating agent by post-synthetic microwave heating

Mesoporous silica SBA-15 samples were subjected to microwave heating for 10–40 min at 393 and 443 K after dry-impregnation with TPAOH (tetrapropylammonium hydroxide) to prepare a mesoporous material with zeolytically ordered pore walls. Physicochemical properties of the materials prepared were characterized by XRD, N₂ adsorption at 77 K, SEM, TEM, UV–vis and FT-IR spectroscopies. These investigations revealed that selective transformation of amorphous pore walls of SBA-15 to crystalline zeolytic phase is difficult to be achieved and a mixed phase of mesoporous silica/zeolite composite material was obtained, instead. Microwave heating time, temperature, TPAOH concentration, and hydrothermal stability of the mesoporous host materials tested (MCM-41, HMS, and SBA-15) were important factors to maintain the mesopore structure of the host materials during the post-synthetic microwave heating treatment.     

Mesoporous silica supports for improved thermal stability in supported Au catalysts

In this work, we present a comprehensive review of our research on the role of mesoporous silica pore architecture, composition of the pore walls (addition of Co or Al), and silica surface chemistry (surface modification by TiO₂) to improve the hydrothermal stability of Au particles. We have found that mesoporous silica architecture plays an important role in improving Au stability, with three dimensional mesoporous architectures being less effective than one dimensional (1-D) pores. The tortuous 1-D pores in aerosol silica were found to be most effective at controlling Au particle size. Since Au particles continue to grow larger than the pore diameter, we conclude that Ostwald ripening must be the dominant sintering pathway for these Au catalysts. These catalysts are active for CO oxidation even after the Au particles have grown large enough to block the pores, suggesting that the thin walls of mesoporous silica provide easy access to gas phase molecules. Further improvements in Au stability and reactivity were obtained by surface modification of the aerosol and MCM-41 silica with TiO₂. After TiO₂ modification of the silica, the Au particles remained smaller than the pore size (< 3 nm) even after three cycles of CO oxidation at temperatures up to 400 °C.     

Synthesis and characterization of highly ordered mesoporous YSZ by tri-block copolymer

A highly ordered mesoporous yttria-stabilized zirconia (YSZ) has been successfully prepared by evaporation-induced self-assembly method (EISA) using tri-block copolymer Pluronic F127 as a structure-directing agent and inorganic chlorides as precursors in a non-aqueous medium. The characterization of the mesoporous YSZ materials was carried out by using small angle X-ray diffraction (SAXRD), transmission electron microscopy (TEM) and N₂ adsorption/desorption. The well ordered mesoporous YSZ is thermally stable up to 600^°C with an average pore size of 5.4 nm and specific surface area of 90 m²/g. The walls of mesoporous YSZ are composed of ～6.5 nm nano-crystalline domains.     

中孔碳负载Pt催化剂用于抗氧剂7PPD合成反应

以纳米氧化锌为模板剂,酚醛树脂为碳源,通过硬模板法制备了中孔碳,并以其为载体制备了Pt/MC催化剂,通过BET、SEM、ICP、TEM等表征手段对中孔碳及其负载的Pt/MC催化剂进行表征。结果表明,可以通过模板剂有效调控中孔碳的比表面积和孔结构。将制备的Pt/MC催化剂用于抗氧剂7PPD合成反应,对比普通Pt/AC催化剂,p-ADPA的转化率由97.5%提高至100%,7PPD选择性由94.5%提高至99.5%,催化剂的稳定性明显提高。通过CO化学吸附、ICP、BET等对新鲜和使用十次后的催化剂进行表征,结果表明,催化剂载体的孔结构是影响催化剂稳定性的重要因素,平均孔径较小时,7PPD等大分子尺寸的分子容易堵塞孔道;平均孔径较大时,孔壁较薄,催化剂使用过程中容易磨损,活性组分流失。