介孔与介孔主客体材料在催化领域的应用

 综述了近年来介孔分子筛催化材料制备的研究成果及其在催化领域特别是精细化学品合成中的应用. 文章分为两部分,分别讨论了介孔材料本身作为催化剂以及介孔主客体催化材料的应用.     

非硅基介孔材料和介孔复合体的合成与特性

非硅基介孔材料和介孔复合体的合成与特性;介孔固体;介孔复合体;二氧化钛薄膜;液晶模板机理     

新型介孔固体碱材料的合成*

介孔固体碱能够催化各式各样的化学反应,降低生产成本并减少对环境的污染,可望代替液体碱成为新一代环境友好催化材料。介孔材料的飞速发展为介孔固体碱的研制提供了契机,到目前为止,研究人员已经采用不同途径合成出了多种类型的介孔固体碱材料。本文以主体材料作为线索,综述了在介孔氧化硅、介孔氧化铝、介孔氧化锆和介孔炭上产生碱性位的方法,描述了所制得固体碱的结构、性质及其在催化反应中的应用。在此基础上,评价了这些制备方法的优缺点,剖析了碱性位产生机理,并对介孔固体碱的发展前景进行了展望。     

Dealloying of Mesoporous PtCu Alloy Film for the Synthesis of Mesoporous Pt Films with High Electrocatalytic Activity

Mesoporous Pt film with highly electrocatalytic activity is successfully synthesized by dealloying of mesoporous PtCu alloy film prepared through electrochemical micelle assembly. The resulting mesoporous electrode exhibits high current density and superior stability toward the methanol oxidation reaction.     

有序介孔碳的合成及其相转变机理的研究

采用十六烷基三甲基溴化铵(CTAB)作为模板剂, 正硅酸乙酯(TEOS)为硅源, 在碱性条件下, 用低温合成方法合成了有序介孔硅, 并以此为硬模板, 蔗糖为碳前驱体, 采用液相浸渍方法填充碳源, 制备出有序介孔碳. 通过XRD、TEM、N₂吸附-脱附等测试方法对其表征, 结果表明合成的介孔材料高度有序, 均具有很高的比表面积(介孔硅, 992～1096 m²/g; 介孔碳, 930～1208 m²/g), 较大的孔容和较窄的孔径分布. 还发现随着反应温度的升高, 介孔硅的结构从二维六方相(p6mm)转变为三维立方相(Ia3d); 介孔碳在复制介孔硅后, 其结构也从三维立方相(Ia3d)转变为四方相(I4₁/a), 并对相转变机理做了初步探讨.     

Mesoporous Trimetallic PtPdRu Spheres as Superior Electrocatalysts

Mesoporous Trimetallic PtPdRu Spheres with well‐defined spherical morphology and uniformly sized pores were synthesized in an aqueous solution using ascorbic acid as the reducing agent and triblock copolymer F127 as the pore directing agent. These mesoporous PtPdRu spheres exhibited enhanced electrocatalytic activity compared to commercial Pt black, resulting in a ～4.9 times improvement in mass activity for the methanol oxidation reaction. The excellent electrocatalytic activity and stability are due to the unique mesoporous architecture and electronic landscape between different elements.     

中空纳米二氧化硅微球的制备及表征

本文介绍了一种制备中空纳米二氧化硅微球的新方法。利用模板首先合成介孔纳米二氧化硅微球,再用水热反应法,成功制备了非功能化和巯基、氨基功能化中空纳米二氧化硅微球。利用透射电子显微镜,热重分析等手段对其形貌进行了表征。另外,对中空介孔纳米二氧化硅微球的形成机制进行了探讨。     

Polysiloxane-Modified Mesoporous Materials

We report the preparation of polysiloxane-modified mesoporous silica gels derived from the acid catalysed hydrolysis of tetraethoxysilane (TEOS) and oligomeric silanol terminated polydimethylsiloxane (PDMS) in the presence of the non-ionic surfactant, octaethylene glycol monohexadecyl ether. The gels were characterised using thermal gravimetric analysis (TGA), infra-red (IR) spectroscopy, X-ray diffraction (XRD) and ²⁹Si solid state cross-polarisation (CP) magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. TGA and IR spectroscopy showed the loss of surfactant after calcination and a decrease in the Si–OH band at 950 cm^–1 indicated further condensation had occurred. This was confirmed by the increase in Q⁴ at –110 ppm, in ²⁹Si MAS NMR spectroscopy, which also showed that calcination had led to the redistribution of PDMS forming a T species. XRD data showed ordering within the structure, with an initial d-spacing of 45 Å, decreasing to 35 Å after calcination.     

钛硅介孔分子筛

综述了钛硅介孔分子筛的合成、表征及其应用研究进展.评述了钛硅介孔分子筛的合成方法与合成条件对分子筛结构性能、钛物种的配位状态和催化性能的影响.介绍了鉴定钛硅介孔分子筛内骨架钛原子的多种波谱学方法以及钛硅介孔分子筛在选择氧化、光催化、酸催化反应中的应用,并指出钛硅介孔分子筛是一种非常有应用前景的环境友好的多相催化剂.     

Periodic Mesoporous Organosilica in Confined Environments

Confined tubes : Periodic mesoporous organosilica (PMO) mesophases were synthesized within the confined tubular environment of anodic alumina membrane (AAM) channels, resulting in the formation of either the hexagonal circular or the cubic mesophase.

     

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.     

Ti-Si介孔分子筛的转晶与控制

以季铵盐型阳离子Gemini表面活性剂[C16H33(CH3)2N+(CH2)6N+(CH3)2C16H33]•2Br−(GEM16-6-16)为模板剂, 改变n(Ti)/n(Si)比值, 合成了系列Ti-Si介孔分子筛. X射线衍射(XRD)和透射电子显微镜(TEM)等表征结果表明, 在n(Ti)/n(Si)≤0.20时, 分子筛为高度有序六方介孔; 当 n(Ti)/n(Si)为 0.30时, 介孔转晶为立方相; 当n(Ti)/n(Si)为0.50时, 介孔转晶为层状相; n(Ti)/n(Si)为1.0时, 材料失去有序孔道结构. FT-IR分析表明, 在分子筛骨架间形成了Ti—O—Si键, 而且Ti—O—Si键的数目随n(Ti)/n(Si)的增加而增加, 达到一定饱和值后基本保持不变. 乙醇和丁醇对纯硅基介孔分子筛孔结构转晶控制作用呈现六方相→立方相→层状相递变规律, 因而钛酸正丁酯水解生成的丁醇对Ti-Si介孔分子筛转晶具有一定的控制作用.     

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.     

不同酸对介孔二氧化硅球表面形貌和介相结构的影响

在室温、不同酸性条件下合成出微米级球形介孔二氧化硅材料，通过XRD、SEM以及氮气吸附等手段对介孔二氧化硅材料进行了表征。用TEM跟踪不同反应时间介孔二氧化硅球的形成，对这些球颗粒的合成机理进行了讨论，同时探讨了不同酸性条件下介孔二氧化硅表面形貌和介相结构的变化。     

Mechanochemical Synthesis of Ruthenium Cluster@Ordered Mesoporous Carbon Catalysts by Synergetic Dual Templates

Ruthenium (Ru)@Ordered mesoporous carbon (OMC) is a key catalyst in fine-chemical production. In general, the OMC support is prepared by a wet self-assembly requiring excessive solvent, toxic phenol–aldehyde precursors and a long reaction time, followed by post-immobilization to load Ru species. Herein, we wish to report a solid-state, rapid, and green strategy for the synthesis of Ru@OMC with biomass tannin as the precursor. The chemistry essence of this strategy lies in the mechanical-force-driven assembly, during which tannin-metal (Zn²⁺ and Ru³⁺) coordination polymerization and hydrogen-bonding interactions between tannin-block copolymer (PEO-PPO-PEO, F127) simultaneously occur. After thermal treatment, Ru@OMC catalysts with mesoporous channels, narrow pore-size distribution (≈7 nm), and high surface area (up to 779 m² g⁻¹) were directed by F127 micelles. Meanwhile, the Zn²⁺ ions dilute Ru³⁺ and avoid the sintering of Ru species, resulting in Ru clusters around 1.4–1.7 nm during carbonization (800 °C). Moreover, the Ru@OMC catalyst afforded a good activity (TOF: up to 4170 h⁻¹) in the selective oxidation of benzyl alcohol to benzaldehyde by molecular oxygen.     

超声波合成介孔分子筛

介孔分子筛MCM鄄41自问世以来一直是材料研究的热门领域之一[1,2],目前报道的主要合成方法有水热合成法[3,4]、微波法[5,6]等。其中水热法反应时间长达3~5d,耗能大,不利于实用化生产。超声波化学又称声化学,是一门新兴的交叉学科。超声波的波长远大于分子尺寸,因而不能对分子直     

高功率超级电容器用介孔炭电极材料

以纳米CaCO3为模板、蔗糖为前躯体制备超级电容器用介孔炭电极材料.材料的结构由氮吸附、TEM表征,借助恒流充放电、循环伏安和交流阻抗评价了其在6 mol.L-1KOH电解液中的电化学电容性能.结果表明,蔗糖基介孔炭的比表面积606 m2/g,富含10~30 nm的介孔.恒流放电法测得介孔炭在电流密度50 mA/g下的比电容为125 F/g,大电流倍率性能特别突出.电流密度增大到20 000 mA/g,比电容还保持有88F/g,远高于进口电容炭,该介孔炭是一种很有前景的高功率超级电容器炭电极材料.     

Mesoporous Silica and Organosilica Films Templated by Nanocrystalline Chitin

Liquid crystalline phases can be used to impart order into inorganic solids, creating materials that mimic natural architectures. Herein, mesoporous silica and organosilica films with layered structures and high surface areas have been templated by nanocrystalline chitin. Aqueous suspensions of spindle‐shaped chitin nanocrystals were prepared by sequential deacetylation and hydrolysis of chitin fibrils isolated from king crab shells. The nanocrystalline chitin self‐assembles into a nematic liquid‐crystalline phase that has been used to template silica and organosilica composites. Removal of the chitin template by either calcination or sulfuric‐acid‐catalyzed hydrolysis gave mesoporous silica and ethylene‐bridged organosilica films. The large, crack‐free mesoporous films have layered structures with features that originate from the nematic organization of the nanocrystalline chitin.     

null

综述了近几年介孔分子筛在催化反应、生物固定吸附和分离、纳米材料制备及环保方面等方面应用研究的进展，并对其在环保方面，尤其是汽油脱硫的应用前景做了展望。