含钨介孔SiO2的合成、表征及其催化性能

分别以廉价硅酸钠与正硅酸乙酯为硅源,通过复合模板剂制备了介孔二氧化硅,并利用吸附相反应技术合成了WO3/SiO2复合催化剂。用XRD,TEM等手段对其结构进行了表征,通过油酸的催化氧化反应考察了催化剂的催化性能。     

超亲水性含钛介孔SiO2薄膜的制备及其自洁净性能研究

采用溶胶-凝胶/旋转涂覆法在玻璃基板表面制备含钛介孔SiO2薄膜.利用XRD、UV-Vis以及接触角测量仪对薄膜的孔结构和超亲水性进行表征.结果表明,当Ti/Si物质的量比为0～0.05时,薄膜均具有良好的介孔结构;而随着Ti/Si物质的量比的增加,薄膜的介孔有序度下降.即使在无光照条件下,含钛介孔SiO2薄膜也表现出高效的超亲水性.涂有油酸的薄膜在紫外光照射后恢复其超亲水性,且薄膜对甲基橙具有良好的光催化降解效果,表明制备的含钛介孔SiO2薄膜具有良好的自洁净性能.     

介孔复合催化剂WO3/SiO2催化合成壬二酸的研究

以油酸为原料,以自制的介孔WO3/SiO2为催化剂,研究了以H2O2为氧化剂制取壬二酸的过程.系统地考察了催化剂中的Si/W、催化剂用量、H2O2用量与加入方式、反应时间等对壬二酸收率产生的影响.通过实验得到的最佳工艺条件为:油酸20g、叔丁醇50mL、wO3/介孔SiO2催化剂0.5g、30％H2O235g,加热回流...     

介孔-大孔HPW/TiO2催化剂的制备及其催化氧化脱硫性能的研究

为了有效降低SO_x在环境中的排放,以嵌段共聚物F127和新合成的PMMA微球为双模板,采用溶胶-凝胶法制备了三维有序介孔-大孔x-HPW/TiO₂催化剂。利用扫描电镜、透射电镜、氮气吸附-脱附、X射线衍射和红外光谱研究了其结构,并考察了其催化氧化燃油中有机硫的性能。结果表明,x-HPW/TiO₂催化剂中存在高度有序的介孔-大孔结构,Keggin结构的HPW均匀分散在TiO₂孔道骨架中。该催化剂在常压、60℃下可使燃油中的二苯并噻吩（DBT）催化氧化完全,循环使用6次后对DBT的去除率仍可达到96%。     

介孔SiO2吸附CO2的性能研究

以正硅酸乙酯（TEOS）为硅源,端氨基聚氧化丙烯醚（D2000）为模板剂,在水和乙醇的混合溶液中合成了蠕虫状介孔结构的介孔SiO₂（记为MSU-J）。采用物理浸渍的方法利用四乙烯五胺（TEPA）改性介孔MSU-J。采用红外、N₂吸附/脱附、元素分析表征改性介孔SiO₂。红外测试表明,经过物理浸渍可以将有机胺负载到介孔SiO₂上。N₂吸附/脱附试验表明,经过氨基修饰后,介孔SiO₂的介孔结构没有发生变化,但是介孔的孔容、孔径以及比表面积随着氨基浸渍量的增加而减小。在25℃和45℃,0.1 MPa下的纯CO₂吸附试验表明,氨基改性材料对CO₂吸附效果明显提高。当浸渍量为20%、吸附条件为25℃/0.1 MPa时,吸附量达到最大值138.6mg/g。当氨基含量继续增加时,吸附量反而降低。循环性试验表明,制备的吸附剂具有良好的循环性能,循环使用6次,材料的吸附量下降很少。     

含钛介孔分子筛的合成与催化性能

论述了含钛介孔分子筛的水热合成、室温合成、微波合成和选择不同模板剂与嫁接法等合成方法及其特点。对含钛介孔分子筛的表面修饰与改性技术进行了概述。总结了含钛介孔分子筛在催化氧化、烯烃环氧化、羟基化和光催化等反应中的催化性能。指出今后的研究方向是:高水热稳定性含钛介孔分子筛的合成方法;通过对含钛介孔分子筛进行表面修饰,制备出具有独特性能的催化材料;含钛介孔分子筛在光催化及其他催化反应中的催化作用机理。     

介孔CuO-ZnO/SiO_2催化剂用于二氧化碳加氢合成甲醇的研究

采用原位溶胶-凝胶法制备了介孔CuO-ZnO/SiO_2催化剂,考察了表面活性剂类型和焙烧温度对催化剂结构和催化性能的影响。以二氧化碳加氢合成甲醇为探针反应,并结合TG-DTG、BET表征手段对催化剂结构和性能进行了分析。结果表明,采用CTAB为表面活性剂并经450℃焙烧所得的介孔CuO-ZnO/SiO_2催化剂具有高的比表面积和最佳的催化性能;反应条件250℃、3.0 MPa时,该催化剂的CO_2转化率、甲醇选择性分别为21.6%和35.6%。     

超亲水性介孔SiO2/Bi2O3/TiO2分层薄膜的制备及其自洁净性能研究

采用溶胶-凝胶/旋转涂覆法在玻璃基板表面制备介孔SiO2/Bi2 O3/TiO2分层薄膜.采用XRD、UV-vis及表面接触角测量仪对薄膜的结构、透光性及超亲水性进行分析.结果表明,介孔SiO2/Bi2 O3/TiO2分层薄膜仍然保持了表面SiO2的介孔结构,在无光照条件下仍具有超亲水性.涂有硬脂酸的薄膜在紫外光照射后恢复了其超亲水性,具有良好的自洁净性能.且SiO2/Bi2 O3/TiO2分层薄膜表现出比单独的SiO2/TiO2和SiO2/Bi2O3分层薄膜更高的光催化活性.     

复合介孔材料磷钼酸/二氧化硅的合成及其催化性能

合成了一种新型磷钼酸/二氧化硅(HPMo/SiO2)复合介孔材料.在酸性条件合成介孔SiO2的过程中直接加入磷钼酸,磷钼酸通过与硅羟基的氧键作用结合并随着硅物种的缩聚而固载在Si02骨架上.研究结果表明HPMo分子均匀地包藏到介孔SiO2网络组成的孔壁中.该材料在有机硫化物二苯并噻吩的氧化反应中具有很高的催化活性和良好的重复使用性能.     

介孔SiO2负载SO2-4/ZrO2固体超强酸催化剂的制备及其酯化催化活性研究

以稻壳SiO2为原料,非离子表面活性剂TX-100为模板,制备了介孔SiO2(MSU-2)及其负载SO2-4/ZrO2固体超强酸催化剂.以乙酸和正丁醇的酯化反应为探针,研究了载体类型、ZrO2的负载量、催化剂用量和反应时间对催化剂性能的影响.结果发现,当SO2-4/ZrO2的负载量在10wt%以上时,催化剂具有超强酸性;SO2-4/ZrO2负载量为20wt%时,催化剂(SO2-4/ZrO2/MS-60)具有最优的催化酯化反应活性.     

磺酸基官能化介孔材料的表征及其催化性能

由高水热稳定的巯基官能化介孔硅基材料经氧化得到磺酸基官能化介孔固体酸催化剂。经过一系列的表征测试,所得固体酸具有发达的孔道结构和大量Br尴nsted酸性位。将其应用于苯甲醛与醇类缩合反应中,与传统沸石固体酸催化剂HY相比,显示了更好的催化性能,缩醛收率在90%左右。所合成的磺酸基官能化介孔固体酸催化剂的催化性能基本不受醇类分子体积影响,具有很好的重复使用性能。     

ZnO/介孔SiO2组装体的制备和表征

在碱性条件下,以正硅酸乙酯和表面活性剂制备了球状的介孔二氧化硅,然后在减压的条件下用醋酸锌溶液浸渍,过滤干燥后在600℃下焙烧5 h制备出了球状的ZnO/介孔SiO2组装体,产物用XRD,TEM,BET,TG,IR进行了表征,结果表明介孔二氧化硅球上负载了ZnO纳米粒子。     

Fe-HMS的合成、表征及催化苯酚羟基化

以正硅酸乙酯(TEOS)、三氯化铁为原料,十二胺(DDA)为模板剂,采用溶胶-凝胶法合成了铁改性六方介孔硅分子筛(Fe-HMS),利用XRD、FTIR、UV-vis、ESR、TG-DTA、ESEM、TEM及N2吸附-脱附技术对材料结构进行了表征,同时以苯酚羟基化反应为探针考察了Fe-HMS的催化性能。结果表明,Fe-HMS材料由细小的球状纳米粒子组成,材料具有稳定的六方介孔结构,铁已进入六方介孔硅(HMS)载体的骨架;在苯酚羟基化反应中材料显示出较高的催化活性,苯酚的转化率最高可达46.9%,催化剂经450℃焙烧2 h即可再生,重复使用7次苯酚转化率仍可达36.4%。     

六方介孔氧化硅负载磷钨酸的催化性能

采用浸渍法将磷钨酸(HPW)负载于六方介孔氧化硅(HMS)上,制备HPW改性HMS介孔材料HPW/HMS,对其进行了表征;以HPW/HMS为催化剂,催化2-萘甲醚(2-MN)与乙酸酐(AA)的酰化反应,考察了各因素对催化反应的影响. 结果表明,HPW高度分散在HMS上,HPW/HMS的酸量和酸强度随HPW负载量增加而增加. 在温度120℃、时间4 h、催化剂用量0.3 g及2-萘甲醚/乙酸酐摩尔比1:2条件下,2-萘甲醚转化率为75.3%(mol),目标产物2-甲氧基-1-萘乙酮的选择性达83.0%(mol). 催化剂可回收再利用,催化活性略有降低.     

介孔SiO_2表面的氨基修饰及吸附性能研究

以十六胺为模板剂、正硅酸乙酯为硅源合成了多孔球形结构的介孔SiO2,用γ-氨基丙基三乙氧基硅烷(ATES)对介孔SiO2进行了表面修饰,得到了氨基嫁接介孔ATES-SiO2。利用XRD、BET、IR等方法分别测定了SiO2和ATES-SiO2的结构与性质,结果表明-NH2已成功接枝于介孔ATES-SiO2的孔道内表面。在常温常压下测得介孔SiO2和ATES-SiO2对CO2的吸附量分别为0.93 mmol/g和4.87 mmol/g。     

Preparation of Polyaniline/Mesoporous Silica Hybrid and Its Electrochemical Properties

Polyaniline/mesoporous silica hybrids were prepared by chemical modification with aniline and their capacitances were examined for application to electrode of electrochemical capacitor. The chemical modification was performed by two kinds of processes, polymer insertion into pores and in-situ polymerization within pores. In the case of the polymer insertion process, since the mean pore sizes of the hybrid did not change, polyaniline molecules were not inserted. On the other hand, in the case of the in-situ polymerization process, the mean pore sizes decreased from that of mesoporous silica, while the XRD patterns became broad. Therefore, aniline molecules polymerized in the inside of pores, however, the mesoporous silica collapsed in part. Maximum capacitance measured in 1 mol/l H₂SO₄ aqueous solution was around 226 F per unit mass of polyaniline.     

Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction

Mesoporous silica with covalently bound salicylic acid molecules incorporated in the structure was synthesized with a one-pot, co-condensation reaction at room temperature. The as-synthesized material has a large surface area, uniform particle size, and an ordered pore structure as determined by characterization with transmission electron microscopy, thermal gravimetric analysis, and infrared spectra, etc. Using the strong fluorescence and metal coordination capability of salicylic acid, functionalized mesoporous silica (FMS) was developed to track and extract radionuclide contaminants, such as uranyl [U(VI)] ions encountered in subsurface environments. Adsorption measurements showed a strong affinity of the FMS toward U(VI) with a K_d value of 10⁵ mL/g, which is four orders of magnitude higher than the adsorption of U(VI) onto most of the sediments in natural environments. The new materials have a potential for synergistic environmental monitoring and remediation of the radionuclide U(VI) from contaminated subsurface environments.     

Novel Two-Step Synthesis of Controlled Size and Shape Platinum Nanoparticles Encapsulated in Mesoporous Silica

Uniform shape and size platinum nanoparticles encapsulated in mesoporous silica (SBA-15) were prepared in the same solution by a novel two-step method. Platinum nanoparticles were prepared in aqueous solution of K₂PtCl₄, the reduction was carried out by bubbling hydrogen, the capping material was tri-block poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) copolymer. The mesoporous silica was synthesized using the same copolymer as template from tetraethyl orthosilicate by hydrolysis in acidic conditions. The Pt-nanoparticles-in-mesoporous-silica system was characterized by a combination of low-angle powder X-ray diffraction, transmission electron microscopy and N₂ porosimetry. The platinum nanoparticles are encapsulated in the mesopores and retained their size and morphology. It appears that this hybrid material should be a superior three-dimensional high-surface-area catalyst for selective platinum-catalyzed reactions.     

Synthesis, Characterization and Catalytic Properties of Mesoporous Cobalt Aluminophosphate Molecular Sieves

Isomorphously substituted cobalt(II) hexagonal mesoporous aluminophosphate (CoHMA) molecular sieves were synthesized hydrothermally and characterized by various analytical and spectroscopic techniques. It was deduced that cobalt ions exhibit a divalent oxidation state in tetrahedral coordination in mesoporous aluminophosphates. Further, unlike cobalt-containing microporous aluminophosphate molecular sieves, Co(II) ions remain in a tetrahedral geometry even after calcination. The catalytic activity of CoHMA was tested for the cyclohexane oxidation reaction under mild conditions. Remarkable substrate conversion and product (cyclohexanol) selectivity were obtained compared to several previously reported heterogeneous catalysts.