微孔磷酸铝AIPO4-HDA的热分解过程研究

采用差热-热重-质谱(TG-DTA-MS)、粉末X射线衍射(XRD)、红外光谱(FTIR)和固体核磁(Solid-State-MAS-NMR)等技术详细地研究了微孔磷酸铝晶体AlPO4-HDA中模板剂的热分解过程.结果表明,该模板剂的热分解分3步进行:第一步是模板剂和无机骨架之间的部分氢键断裂;第二步为模板剂的Hof-mann降解反应和β-消除反应;第三步是残留积碳的氧化分解反应.固体MASNMR的研究结果表明,随着模板剂的脱出.无机骨架中铝和磷的配位状态发生了变化.     

酸法纳米纤维素模板剂合成介孔TiO2及光催化活性

以生物可再生资源的酸法纳米纤维素为模板剂,四氯化钛为钛源,采用液相水解-沉淀法制备了具有介孔结构的TiO2光催化剂。采用低温N2物理吸附-脱附、透射电镜(TEM)、X射线衍射(XRD)、热重-量热扫描(TG/DSC)、傅里叶变换红外(FTIR)、X射线光电子能谱(XPS)等对介孔TiO2进行了表征,并以甲基橙为模型物,考察了介孔TiO2光催化活性。结果表明,以酸法纳米纤维素为模板剂合成的TiO2光催化活性显著提高,且具有良好的孔隙结构,平均孔径5.03 nm、总孔容积0.35 cm3.g-1、比表面积192m2.g-1;纤维素模板剂合成的TiO2表面羟基数量降低;纤维素长链分子结构之间的羟基与TiO2表面羟基的键合,可有效限制TiO2前驱体的生长和团聚,并抑制锐钛矿相TiO2向金红石相转变。     

阳极氧化铝模板合成介孔CeO2纳米纤维及其光致发光性能

以多孔阳极氧化铝膜(AAO)为模板,将模板的纳米孔洞作为微腔反应器,以聚环氧乙烯醚-聚环氧丙烯醚-聚环氧乙烯醚三嵌段共聚物(P123)为致孔剂、Ce(NO3)3.6H2O为铈源、无水乙醇为溶剂合成前躯体,采用压力诱导的方法将前躯体注入到AAO孔道内,经加热处理后,在模板的纳米孔洞内合成了具有介孔结构的一维CeO2纳米材料。通过SEM、TEM、XRD、EDS和N2吸附-脱附进行表征,结果表明,所合成的介孔CeO2纳米纤维具有介孔结构和较大的比表面积,并考察了其光致发光性能。     

分子印迹技术制备石油有机硫组分固相萃取剂的研究

用分子印迹技术合成了对石油有机硫组分二苯并噻吩(Dibenzothiophene，DBT)具有高效选择性的分子模板聚合物(Molecularly Imprinted Polymer，MIP)，通过静态吸附的方法研究了不同功能单体和致孔剂及其用量对模板聚合物特异性识别能力的影响．实验表明，以4-乙烯基吡啶(4-VP)为功能单体，在甲苯溶剂中聚合得到的固相萃取剂对DBT具有较大的吸附富集能力和识别特性．其饱和吸附容量达到48．3mg／g．     

用TEAOH-C4H9NO复合模板剂合成SAPO-34分子筛的研究Ⅱ.SAPO-34分子筛的表面酸性和催化性能

 以吗啉(C4H9NO)为主要模板剂,以少量四乙基氢氧化铵(TEAOH)为辅助模板剂合成了SAPO -34分子筛,并用氨吸附红外、核磁共振和氮吸附等手段对合成的SAPO-34分子筛进行了表 征. 结果表明,与单独以吗啉为模板剂合成的样品相比,用复合模板剂合成的分子筛样品的比 表面积和孔体积均有所增大; 由于在分子筛骨架中形成了“硅岛”,使其B酸量有所增加 ,对甲醇制低碳烯烃反应的催化性能有所改善.     

用TEAOH-C4H9NO复合模板剂合成SAPO-34分子筛的研究Ⅰ.SAPO-34分子筛的合成与表征

 以吗啉(C4H9NO)为主要模板剂,以少量四乙基氢氧化铵(TEAOH)为辅助模板剂合成了SAPO -34分子筛,并采用X射线衍射、扫描电镜、傅里叶变换红外光谱和热重-差热分析等手段对 合成的SAPO-34分子筛进行了表征. 结果表明,TEAOH在导向生成SAPO-34分子筛骨架过程中 表现活跃,占据了较多的平衡骨架负电荷的位置,而吗啉主要起到填充分子筛孔道的作用. 用 TEAOH-C4H9NO复合模板剂合成的SAPO-34分子筛,其晶粒远小于单用吗啉模板剂合成的 分子筛.     

以醚胺为模板剂合成含二价金属杂原子的开放骨架磷酸铝化合物M(Ⅱ)-CJ50

在水热体系中, 以2,2'-(乙烯二氧)双(乙胺)为模板剂, 合成了3种含二价金属杂原子的开放骨架磷酸铝化合物M(Ⅱ)-CJ50(|C₆H₁₇N₂O₂| [MAl₃P₄O₁₆], 其中M=Mg, Mn和Fe). 单晶及粉末X射线衍射分析表明, 这3种化合物与以咪唑为模板剂合成的含三价金属杂原子的M(Ⅲ)-CJ50具有相似的骨架拓扑结构. 二者的区别在于: 由于使用了还原性较强的醚胺作模板剂, M(Ⅱ)-CJ50结构中的金属杂原子具有比M(Ⅲ)-CJ50更低的氧化态; M(Ⅱ)-CJ50中的金属杂原子与1个醚胺模板剂分子中的2个醚氧原子形成双齿配位, 而M(Ⅲ)-CJ50中的金属杂原子则与2个咪唑模板剂分别形成单齿配位. 此外, 磁性测试结果表明, 由于金属杂原子的氧化态以及配体模板剂分子的差异, 导致M(Ⅱ)-CJ50中的过渡金属杂原子处于电子高自旋态, 而M(Ⅲ)-CJ50中的杂原子则处于低自旋态.     

原位合成苯并咪唑衍生物调控一维PbI_3~-盐的晶体结构和光学性质

以原位N-烷基化合成的苯并咪唑衍生物R2-bzim(R=H-,CH3-,C6H5CH2-;bzim=苯并咪唑)为模板,合成了3个含一维PbI3-盐的无机-有机杂化材料.X射线单晶衍射结果表明,随着模板剂尺寸的增大一维无机链由双链结构转变为单链结构.相对于体相PbI2,这些化合物有0.38～0.46eV的带隙蓝移,体现出比较强的量子限域效应.光致发光研究表明,通过模板剂的调控,3个化合物分别表现出绿、橙、黄光发射.     

聚合有机凝胶印迹膜对D-和L-苯丙氨酸的选择性吸附

以1-甲基-2,4-二(N’-十八烷脲基)苯为凝胶剂,以液体单体丙烯酸-2-乙基己酯、甲基丙烯酸甲酯、二甲基丙烯酸聚乙二醇(200)酯以及模版分子和光敏引发剂的混合物为溶剂,研究表明,这种二烷基脲型凝胶剂在这些单体混合物中可进行超分子自组装,形成互相缠绕的具有纳米尺寸的纤维状聚集体,最终导致这些单体混合物首先形成稳定的超分子有机凝胶。然后经UV光引发聚合,经乙醇抽提凝胶剂聚集体和模板分子,制备了一种新型分子印迹的聚合有机凝胶薄膜。探讨了不同凝胶剂浓度、模板分子浓度、单体混合物配比所制备的印迹聚合有机凝胶薄膜对D-和L-苯丙氨酸吸附效率的影响。结果表明所制备的印迹聚合超分子凝胶对L-苯丙氨酸吸附效率约为对D-苯丙氨酸吸附效率的3～4倍,表现出明显的选择性吸附性。     

单一模板线性多胺一步合成多级孔ZSM-5沸石微球

线性多胺模板剂(二乙烯三胺(DETA)、三乙烯四胺(TETA)、四乙烯五胺(TEPA))作为单一模板合成了均匀的10-15 μm的多级孔沸石ZSM-5微球. 实验发现, 在水热过程中, 50 nm纳米的沸石晶体粒子自发地堆积成微球, 并且这些微球具有较大的介孔体积, 在傅-克烷基化反应中具有高的催化活性. 同时,我们发现线性多胺起到了模板剂和空隙填充剂的多重功能,这点明显不同于以前我们报道的线性二胺作为模板剂在合成ZSM-5沸石时,主要是起模板剂的作用.     

Gas diffusion and microstructural properties of ordered mesoporous silica fibers

Pore and surface diffusion of carbon dioxide (CO(2)) and ethylene (C(2)H(4)) in the nanopores of ordered mesoporous silica fibers about 200 microm in length was measured by the transient gravimetric method. The experimentally determined pore diffusivity data, coupled with the porosity, pore size, and fiber length, are used to obtain the actual length of the nanopores in silica fibers. These measurements reveal a structure of the ordered nanopores whirling helically around the fiber axis with a spiral diameter of about 15 microm and a pitch value of 1.6 microm. At room temperature the surface diffusion contributes about 10% to the total diffusional flux for these two gases in the nanopores of the ordered mesoporous silica fibers. The surface diffusion coefficients for the ordered mesoporous silica fibers are about 1 order of magnitude larger than the non-ordered mesoporous alumina or silica with similar pore size.     

PdNi/Ni Nanotubes Assembled by Mesoporous Nanoparticles for Efficient Alkaline Ethanol Oxidation Reaction

The optimization of structure and composition is essential to improve the performance of catalysts. Herein, mesoporous nanoparticles assembled PdNi/Ni nanotubes (mPdNi/Ni NTs) are successfully fabricated using nickel nanowires as sacrificial template. The combination of nanotubular structure with mesoporous nanoparticle morphology can provide facilitated transfer channels and sufficient active sites, allowing the full contact and reaction between catalysts and reactants. Therefore, the synthesized mPdNi/Ni NTs exhibite superior ethanol oxidation performance to mesoporous Pd nanotubes and commercial Pd black. This study proposes a rational strategy for the development of nanoparticle assembled nanotubes with surface mesoporous morphology, which can greatly improve catalytic performance in various electrocatalytic fields.     

Advances in the Interfacial Assembly of Mesoporous Silica on Magnetite Particles

Interfacing magnetic particles with ordered mesoporous materials is an effective direction for the development of functional porous composite materials with rationally designed core–shell structures. Owing to the combined properties of magnetic nanoparticles and mesoporous silica (high surface area, large pore volume, porosity, and biocompatibility), core–shell magnetic mesoporous silica materials have generated tremendous interest in various disciplines, including chemistry, materials, bioengineering, and biomedicine. Interfacial assembly strategies enable the rational construction of magnetic mesoporous silica materials with well‐defined core–shell structure, morphology, pore parameters, and surface wettability, which can decisively influence their physical and chemical properties and thus improve their application performance. This Minireview summarizes recent progress in the synthesis of core–shell magnetic mesoporous silica and the adjustment of key parameters, including pore size, morphology, and pore orientation.     

以介孔分子筛为金属催化剂载体制备纳米碳管

 以不同的介孔分子筛作为金属催化剂载体,对催化合成纳米碳管进行了系统的研究,讨论了反应条件对纳米碳管纯度和产量的影响. 结果表明,不同的介孔分子筛对金属活性中心的形成、碳组分的扩散、纳米碳管的管径及形态均有明显的影响. 此外,金属的种类、状态和含量也影响纳米碳管的合成. 探索了合成高产量纳米碳管的条件,并对介孔分子筛上生长纳米碳管的特点进行了讨论.     

Visible light driven photocatalytic hydrogen evolution over CdS incorporated mesoporous anatase TiO2 beads

Research on Chemical Intermediates - The synthesis of CdS incorporated mesoporous anatase TiO2 beads is reported in this work. The mesoporous structure, crystalline structure, morphology and...     

Investigation on into the adsorption of Cu(II), Pb(II) and Cr(VI) on hollow mesoporous silica using microcalorimetry

Journal of Thermal Analysis and Calorimetry - Hollow mesoporous silica (SiO2) was synthesized by the modified self-template method, and the morphology and structural properties of mesoporous silica...     

Organic-inorganic hybrid mesoporous silicas: functionalization, pore size, and morphology control

Topological design of mesoporous silica materials, pore architecture, pore size, and morphology are currently major issues in areas such as catalytic conversion of bulky molecules, adsorption, host-guest chemistry, etc. In this sense, we discuss the pore size-controlled mesostructure, framework functionalization, and morphology control of organic-inorganic hybrid mesoporous silicas by which we can improve the applicability of mesoporous materials. First, we explain that the sizes of hexagonal- and cubic-type pores in organic-inorganic hybrid mesoporous silicas are well controlled from 24.3 to 98.0 A by the direct micelle-control method using an organosilica precursor and surfactants with different alkyl chain lengths or triblock copolymers as templates and swelling agents incorporated in the formed micelles. Second, we describe that organic-inorganic hybrid mesoporous materials with various functional groups form various external morphologies such as rod, cauliflower, film, rope, spheroid, monolith, and fiber shapes. Third, we discuss that transition metals (Ti and Ru) and rare-earth ions (Eu(3+) and Tb(3+)) are used to modify organic-inorganic hybrid mesoporous silica materials. Such hybrid mesoporous silica materials are expected to be applied as excellent catalysts for organic reactions, photocatalysis, optical devices, etc.     

仿生介孔二氧化硅用于高效液相色谱拆分手性化合物

仿生介孔硅是以有机物作为模板,可有效复刻模板的独特形貌,从而得到其相同或相似结构孔径的介孔硅。本文从仿生的观点出发,从蟹壳中提取得到几丁质膜,将其用作模板制备了仿生手性向列型介孔二氧化硅,并用其制备了液相色谱柱,进行了手性化合物拆分实验。结果表明,该色谱固定相对10个手性化合物有一定的手性分离效果。     

Synthesis of bifunctionalized mesoporous organosilica spheres for high-performance liquid chromatography

Phenyl-functionalized mesoporous ethane-silicas with spherical morphology were synthesized by one-step co-condensation of phenyltrimethoxysilane (PTMS) and 1,2-bis(trimethoxysily)ethane (BTME) using a triblock copolymer EO(20)PO(70)EO(20) (P123) as template with the aid of a co-surfactant (cetyltrimethylammonium bromide, CTAB) and a co-solvent (ethanol) in acidic medium. Powder X-ray diffraction (XRD), nitrogen sorption measurement and scanning electron microscopy (SEM) show that phenyl-functionalized ethane-silica has wormhole-like mesostructure and perfect spherical morphology. The chemical stability of phenyl-functionalized mesoporous ethane-silica in basic medium is greatly improved owing to the ethane groups bridged in the mesoporous framework. This work also demonstrates that the phenyl-functionalized mesoporous ethane-silica spheres are excellent packing materials for potential application in the reversed-phase high-performance liquid chromatography (HPLC).     

Direct synthesis of ordered mesoporous ZSM-5 zeolites from in situ crystallization of carbonaceous SBA-15

Two types of ordered mesoporous ZSM-5 zeolites with different mesopores were synthesized by a two-step method. First,carbonaceous SBA-15 was produced by in situ carbonization of SBA-15/P123 composite. Then the obtained SBA-15/C composite was transformed into crystallized mesoporous ZSM-5 by impregnation TPAOH followed by steam-assisted crystallization. The final calcined samples synthesized with typical SBA-15/P123 precursor showed a wormlike morphology with the mean mesopore size of 4.6 nm, while samples synthesized with the addition of trimethylbenzene as swelling agent in the precursor exhibited the morphology of microsphere with the mesopore size of about 9.5 nm. Both two types of mesoporous ZSM-5 zeolites exhibited large surface area and mesopore structure. The steam-assisted crystallization(SAC) was performed with lower consumption of solvents. This two-step method may also be suitable for synthesizing other ordered mesoporous zeolites used as catalysts in some catalytic processes.