固体碱催化剂MgO@SBA-15催化大豆油制备生物柴油的研究

以SBA-15分子筛为载体,采用浸渍法通过负载MgO制备了MgO@SBA-15固体碱催化剂,并对其进行了X射线衍射和N2吸附-脱附等分析表征,考察了焙烧温度、MgO负载量、醇油物质的量比和催化剂用量等因素对催化剂性能的影响。结果表明:MgO负载量为15%(质量分数)的MgO@SBA-15催化剂能够很好地保持SBA-15原有的介孔特征,且MgO在SiO2骨架上高度分散;在焙烧温度500℃、MgO负载量为15%时催化剂活性最佳;在醇油物质的量比为9∶1、催化剂用量为大豆油质量的3%、反应时间为3h的条件下,生物柴油的产率达到91.83%。     

简单中和法制备二茂铁介孔SBA-15复合材料

采用一种新颖的简单中和法,利用羧基二茂铁中的羧基与含有氨基的介孔材料SBA-15作用,将二茂铁成功引入介孔SBA- 15孔道中,避免了二茂铁催化剂与催化产物不易分离,重复使用寿命低及腐蚀污染严重的问题.此方法步骤简单,反应条件温和,也可用于制备其他的介孔基复合材料.通过傅立叶红外光谱分析、X射线衍射分析、透射电镜及能谱分析、N2吸附一脱附实验和热-质谱分析表征了样品的性能,实验结果表明,二茂铁与介孔材料SBA-15结合良好.     

胶原纤维为模板TiO_2、La_x/TiO_2纳米纤维的制备、表征及光催化活性研究

以胶原纤维为模板分别负载钛(Ti4+)或钛(Ti4+)和镧(La3+),经高温煅烧制得介孔TiO2和La x/TiO2纳米纤维。通过场发射扫描电镜(FESEM)、N2吸附-脱附等温线、X射线衍射(XRD)、分子荧光光谱(PL)和紫外-可见吸收光谱(UV-Vis)等对这2类纳米纤维的结构和物理性能进行了表征。结果表明胶原纤维的纤维状结构能被较好地保留在TiO2和La x/TiO2纳米纤维中。TiO2和La x/TiO2纳米纤维的N2吸附-脱附等温线属于典型的Ⅳ型,表明其具有介孔结构。XRD分析表明,La3+的掺杂减小了TiO2的晶粒尺寸。与Degussa P25相比,介孔TiO2和La x/TiO2(x≤0.02)纳米纤维的紫外-可见吸收光谱红移,分子荧光光谱强度明显减弱。以孔雀石绿的光催化降解为模型反应,在可见光和紫外光激发下,介孔TiO2和La x/TiO2纳米纤维的光催化活性均高于Degussa P25。此外,La x/TiO2在可见光激发下的光催化活性高于未掺杂的TiO2纳米纤维。     

二次纳米自组装法制备Ni-Mo/TiO2-Al2O3催化剂

依据框架式大孔容介孔固体材料的形成机理,采用二次纳米自组装法制备出高比表面积和大孔容的纳米TiO2-Al2O3载体.应用低温氮吸附、扫描电子显微镜(SEM)和透射电子显微镜(TEM)技术研究了TiO2助剂对TiO2-Al2O3载体的介孔结构和纳米粒子团聚效应的影响,以及浸渍方法对Ni-Mo/TiO2-Al2O3催化剂的孔结构和金属组分分散性的影响.结果表明,适量TiO2对纳米TiO2-Al2O3载体有较好的扩孔和抗聚集效应;二次纳米自组装TiO2-Al2O3(TiO2,20%)粉体具有较大的比表面积和比孔容以及低纳米尺度.分步浸渍法制备的催化剂上Ni-Mo活性组分具有良好的分散性,其分布较宽的介孔系统适合渣油的加氢精制过程.     

三维有序大孔负载Pt-SO_4~(2-)/TiO_2固体超强酸的制备和性能

以一种直径约170nm的PMMA微球胶体晶体为模板,复制出孔径约为95nm的三维有序大孔SiO2,以这种大孔结构为载体,采用浸渍-焙烧法制备了三维有序大孔负载的Pt-SO42-/TiO2固体超强酸催化剂。探讨了TiO2负载量对三维有序大孔结构的影响。采用SEM、XRD、N2吸附-脱附实验对其大孔结构进行了表征。结果表明,适宜的TiO2负载量为30%(质量分数),太低,酸性不强,太高,易产生大孔的堵塞。负载后的大孔孔径约为75nm,呈现一种厚壁的球形大孔结构。与通常的三维有序大孔材料(孔径大于300nm)相比,这种孔径小化的大孔材料具有稳定性高和表面积大的特征。以乙酸和正丁醇的液相酯化反应为探针反应,发现这种大孔固体超强酸催化剂可以明显提高其催化活性。     

pH值敏感介孔纳米复合材料SBA-15/PAA的制备与性能研究

通过浸渍吸附的方法将pH值敏感的功能单体-丙烯酸引入到介孔二氧化硅SBA-15的孔道内,经自由基聚合使丙烯酸(AA)在孔道内聚合,成功合成了pH值敏感的SBA-15/聚丙烯酸(PAA)纳米复合材料,所得纳米复合材料的结构通过XRD、TEM、氮气吸附/脱附、TG、FT-IR等手段进行了表征,并进行了pH敏感性能研究.结果表明,当聚合物(PAA)的量达到20%左右时,复合材料仍然具有较大的孔体积0.5203cm3/g和较高的比表面积334.5m2/g.聚合反应的发生没有破坏SBA-15的有序介孔结构,这种纳米复合材料初步显示出了pH敏感性.这种具有高比表面的pH值响应介孔纳米复合材料,有望在药物缓释领域得到应用.     

双功能化SBA-15的制备及对水中Ni2+的吸附行为

分别以硅烷偶联剂和EDTA-2Na为改性剂,采用后嫁接法,制备出双功能化介孔二氧化硅SBA-15。利用傅里叶红外光谱仪、N2吸附-脱附对样品结构进行了表征,并讨论了吸附热力学特性、吸附动力学特性及吸附等温特性。结果表明,双功能化SBA-15吸附水中Ni 2+时在180min内可以达到吸附平衡,吸附过程为化学吸附与物理吸附共存的过程,吸附过程符合拟二级动力学方程,吸附等温线符合Langmuir模型,基于Langmuir模型计算得出35℃时最大吸附量为31.25mg·g-1。     

纳米浇注法制备有序介孔WC/C复合材料及电催化性能

以介孔SiO2为硬模板,通过纳米浇注法在模板孔道中引入不同质量配比的碳源和钨源前驱物,经过高温碳化还原反应,刻蚀除去模板后得到了介观结构有序的SBA-15和KIT-6介孔碳化钨/炭(WC/C)复合材料。采用XRD、TEM、EDX、TGA、CV和N2吸附-脱附等测试手段,对所得复合材料进行了物化性质分析和结构表征。结果表明,该介孔WC/C复合材料具有有序的介观结构(p6mm,Ia3d)、高的比表面积(约500m2/g)和较大的孔径(约4nm)。CV测试表明,三维贯通的有序TC/C-KIT-6为载体负载Pt催化剂,对甲醇的催化氧化具有更优异的作用。     

复合模板剂自组装制备混晶纳米TiO2介孔材料及其性能研究

采用TiCh为原料,以十六烷基三甲基溴化胺（CTAB）、聚乙二醇（PEG400、PEG6000）及十二烷基苯磺酸钠（SDBS）两两组合为复合模板和结构导向剂,利用常压液相-水热合成两步反应制备了纳米混晶TiO2介孔材料。XRD分析结果表明,产品为金红石-锐钛矿的混晶结构;TEM观察,样品是由均匀球形颗粒组装成的无序介孔材料,一次粒径约为10～15nm;N2吸附-脱附等温曲线形状为Langmuir Ⅳ型,是典型的介孔结构吸附-脱附等温线,最可及孔径约为11nm。光催化性能实验表明,在40W目光灯照射60min后,该系列介孔材料可有效的降解工业废水中的有毒氰根含量和有机染料。研究结果还表明,采用CTAB-SDBS作为复合模板和结构导向剂时制得的介孔材料的孔结构和光催化降解性能较好。     

介孔炭作为加氢脱硫催化剂载体材料的研究

以介孔硅SBA-15为模板,焦糖和呋喃醇为碳源,通过多种浇注法制备介孔炭材料.采用低温氮吸附、透射电镜和X射线小角衍射分析模板及介孔炭的织构.结果显示合成的介孔炭成功地复制了SBA-15的结构.以制备的介孔炭作载体担载钴钼合成了加氢脱硫催化剂,利用X射线能谱、透射电镜能量分布谱及一氧化氮化学吸附评估了催化剂的活性及活性点分布,结果表明介孔炭担载的催化剂活性高于活性炭担载的同类催化剂.     

Synthesis of TiO2 supported on SBA-15 using different method and their photocatalytic activity

SBA-15 mesoporous materials were successfully prepared by the conventional hydrothermal method and TiO2 nanoparticles were supported on them using different loading methods. The synthesized materials were characterized and their activity as photocatalysts for the decomposition of methylene blue was evaluated. The loading of titanium dioxide on the framework of SBA-15 makes the pore diameter and pore volume decrease compared to that of SBA-15. The chelating method causes the support to have a much better dispersion capacity for TiO2 particles as compared to the other two methods. The TiO2 supported by chelating method showed the highest photocatalytic activity among the photocatalysts prepared by different method.     

Investigation of Eu-doped mesoporous titania phosphor with enhanced luminescence

A novel mesoporous TiO2 phosphor doped with Eu was synthesized through a facile hydrothermal synthesis method using cetyltrimethylammonium bromide as structure template reagent. The samples were characterized by X-ray diffraction, N2 adsorption-desorption, scanning electron microscope, high-resolution transmission electron microscopy, ultraviolet visible diffuse reflectance, X-ray photoelectron spectroscopy, and three dimensional Photoluminescence. The X-ray diffraction results demonstrated that the products were anatase type with polycrystalline. N2 adsorption-desorption analysis showed that the samples were of high ordered double mesoporous structures. Eu-doped mesoporous TiO2 indicated the typical fluorescent spectra of Eu3+ ion occurred: the excited-states at 5L6 (394 nm), 5D2 (465 nm) and 5D1 (535 nm); the main emission peaks at 592 and 617 nm, corresponding with the transitions 5D0 --> 7F1 and 5D0 --> 7F2, respectively. Meanwhile, the phenomena of Eu(3+)-doped mesoporous TiO2 phosphor with efficient nonradiative energy transfer from the mesoporous TiO2 host to the activator Eu3+ ions was observed and possible emission mechanism was proposed. High dispersion of Eu in mesoporous TiO2 matrix was responsible for enhanced luminescence.     

Synthesis of nano titania particles embedded in mesoporous SBA-15: characterization and photocatalytic activity

Supported nanocrystalline titanium dioxide (TiO2) has been prepared by a post-synthesis step via Ti-alkoxide hydrolysis through the use of mesoporous SBA-15 silica. TiO2/SBA-15 composites with various TiO2 loading have been prepared and characterized by X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy and diffusive reflective UV-vis spectroscopy. The addition of mesoporous SBA-15 prevents the anatase to rutile phase transformation and the growth of crystal grain. TiO2 did not block the SBA-15 pores, and their surface was fully accessible for nitrogen adsorption. Calcination in air of the composites up to 800 degrees C did not change the nanocrystal phase and slightly increased the domain size from 5.0 to 7.5 nm, indicating that the anatase TiO2 grains in the mesostructures have a relatively high thermal stability and proper pore diameter allows controlling the size of obtained titania particles. The TiO2/SBA-15 composites prepared by this study showed much higher photodegradation ability for methylene blue (MB) than commercial pure TiO2 nanoparticles P-25. Experimental results indicate that the photocatalytic activity of titania/silica mixed materials depends on the adsorption ability of composite and the photocatalytic activity of the titania, and there is an optimal ratio of Ti:Si, too high or low Ti:Si ratio will lower the photodegradation ability of the composites.     

镧(Ⅲ)对SBA-15分子筛改性研究

借助水热法，利用三嵌段共聚物聚(1，2—亚乙基二醇)—嵌段—聚(丙二醇)—嵌段—聚(1，2—亚乙基二醇)为模板剂，正硅酸四乙酯为硅源，强酸性条件下制备了分子筛SBA—15．分别以水及水 乙醇为介质采用LaCl3溶液与煅烧的主体材料SBA—15分子筛固—液相交换法，制备了La—(SBA—15)复合材料．利用化学分析、粉末XRD、N2吸附技术、IR评价了制备方法的有效性及对SBA—15分子筛孔结构的影响．结果表明，镧已并入SBA—15分子筛中，SBA—15内表面上的硅羟基团是镧进入的主要位置，部分客体在分子筛孔道内．制得的材料La—(SBA—15)保持高度有序的介孔二维六角结构，不改变载体SBA—15的介SLSL道结构．此外，考察了La—(SBA—15)产物的发光现象。     

镧(Ⅲ)对SBA-15分子筛改性研究

借助水热法,利用三嵌段共聚物聚(1,2-亚乙基二醇)-嵌段-聚(丙二醇)-嵌段-聚(1,2-亚乙基二醇)为模板剂,正硅酸四乙酯为硅源,强酸性条件下制备了分子筛SBA-15.分别以水及水+乙醇为介质采用LaCl₃溶液与煅烧的主体材料SBA-15分子筛固-液相交换法,制备了La-(SBA-15)复合材料.利用化学分析、粉末XRD、N₂吸附技术、IR评价了制备方法的有效性及对SBA-15分子筛孔结构的影响.结果表明,镧已并入SBA-15分子筛中,SBA-15内表面上的硅羟基团是镧进入的主要位置,部分客体在分子筛孔道内.制得的材料La-(SBA-15)保持高度有序的介孔二维六角结构,不改变载体SBA-15的介孔孔道结构.此外,考察了La-(SBA-15)产物的发光现象.     

介孔SO42-/TiO2的一步法制备及其光催化性能

通过对TiOSO4溶液热水解用一步法制备出大比表面积、高活性的介孔SO42-/TiO2光催化剂.用低温氮吸附-脱附等温线、XRD、Hammett指示剂、艾氏卡等方法对SO42-/TiO2催化剂进行了表征,以亚甲基蓝的光催化氧化降解反应考察了催化剂的光催化性能.结果表明,在焙烧过程中硫酸根和偏钛酸孔壁上的自由羟基键合,不仅有效地抑制了TiO2晶粒的长大和晶相转变,而且起到了孔结构形成的导向及支撑作用,使TiO2保持了介孔结构、较高的比表面积和锐钛矿相,同时S=O键的强电子诱导效应还使邻近的Ti成为超强酸中心,促进了TiO2光生电子-空穴对的分离,延长了电子-空穴对的寿命,从而有效地提高了TiO2的光催化活性.     

In-situ synthesis of Ag/SBA-15 nanocomposites by the “pH-adjusting” method

Ag nanoparticles were incorporated into the channels of mesoporous SBA-15 by the “pH-adjusting” method. In this procedure, the pH value of the solution was adjusted up to 7.5 by adding ammonia. The structural properties of Ag/SBA-15 nanocomposites were systematically investigated by X-ray powder diffraction (XRD), Transmission electron microscope (TEM), N₂ adsorption-desorption isotherms, inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Fourier transform infrared spectroscopy (FT-IR) techniques. The characterization results reveal that the synthesized materials exhibit highly ordered hexagonal mesoporous structures, and highly dispersed Ag nanoparticles are confined inside the mesopores. It is the first time to report such high Ag loading on oxides fabricated by in-situ pH-adjusting method.     

Synthesis of TiO2 supported on SBA-15 using chelating method and their photocatalytic decomposition of methylene blue

SBA-15 mesoporous materials were successfully prepared by the conventional hydrothermal method and used as the support for TiO2 loaded SBA-15 photocatalysts. The synthesized materials were characterized by XRD, PL, FT-IR, BET and TEM. We also examined the activity of these materials as photocatalysts for the decomposition of methylene blue. The loading of titanium dioxide on the framework of SBA-15 makes the pore diameter and the pore volume decrease and decreases the surface area compared to that of SBA-15. For the TiO2 loaded SBA-15 photocatalysts, the IR absorption at approximately 960 cm(-1) is commonly accepted as the characteristic vibration of the Ti-O-Si bond. The PL peaks appears at about 410 nm at a loading ratio of less than 5% but moves to 430 nm at higher loading ratios. It was also shown that the excitonic PL signal is proportional to the photocatalytic activity for the decomposition of methylene blue. The photocatalytic activity increases with increasing TiO2 loading ratio, shows a maximum value at 7% TiO2/SBA-15, and then decreases at 10% TiO2/SBA-15.     

Improving bioavailability of silybin by inclusion into SBA-15 mesoporous silica materials

Mesoporous silica SBA-15 (SC) and template occluded SBA-15 (SP) were used to increase the bioavailability of silybin, an extremely poorly water soluble drug. Silybin was introduced into SC and SP by assembling or self-assembling methods. The results of X-ray powder diffraction, differential scanning calorimetry (DSC) and N2 adsorption-desorption experiment indicated that amorphous silybin was successfully introduced into the mesopores in both SC and SP samples. The transmission electron micrograph (TEM) images revealed that the structure of the mesoporous materials was not destroyed after the drug loading. Results of dissolution rate tests and animal experiments showed that both SC and SP can significantly improve the bioavailability of silybin, SP was thus preferred because the template needs not to be removed by calcination or extraction.