磁性介孔碳复合材料的制备与应用研究进展

磁性介孔碳复合材料兼具介孔碳材料和磁性材料的双重优势,不仅具备较高的比表面积、均一的孔径分布和环境友好等特点,而且还具有良好的磁性分离特性.首先介绍了介孔碳和磁性纳米粒子常见的制备方法,在此基础上重点综述了磁性介孔碳复合材料的制备方法,并比较了各种方法的优缺点,对磁性介孔碳复合材料在生物医药、催化和污水处理等领域的最新应用进行了概述,并展望了其未来的发展趋势.同时,探讨了环境友好的绿色合成路线在磁性介孔碳复合材料方面的优势和挑战.     

ZnS/SiO2介孔组装体系的光吸收特性

通过溶胶-凝胶法获得块材ZnS纳米颗粒／介孔SiO2组装体系(ZnS／SiO2)样品，分别在氮气和空气气氛中做了退火处理，发现吸收边位置随复合量和退火温度不同而移动，经计算颗粒的理论值与其自由激子半径相当，说明吸收边的移动起因于量子限域效应。     

掺杂Co的介孔SiO_2的制备与表征

利用溶胶-凝胶法,在碱性条件下,以正硅酸乙酯和KH550(γ-氨丙基三乙氧基硅烷)为硅源,CTAB为模板制备掺杂Co的介孔SiO2,并用BET、XRD、FT-IR、XPS对所得介孔SiO2进行表征.结果表明:所得介孔SiO2上负载了钴纳米粒子,煅烧温度在400℃的样品的比表面积最大,当温度逐渐提高时所得样品比表面积反而减小;当n(SiO2)∶n(CTAB)为1∶0.20时,所得样品比表面积(514.2 m2.g-1)相对较高,所制备的样品呈双介孔结构.     

Delamination of lamellar phyllosilicate Magadiite

In this paper, a new delaminated mesoporous material was prepared by swelling the lamellar phyllosilicate Magadiite using cetyltrimethylammonium bromide and tetrapropylammonium hydroxide solution, followed by delamination under the cavitation of ultrasonic treatment. Various characterization tools including XRD, N2 adsorption, NMR, IR, SEM and TEM were employed to observe its structure and morphology. XRD results show that the delaminated material has no long-range crystalline order. Fur-thermore, not only high surface area is obtained, but almost half of it is external surface. The observation for the morphology further reveals that it is made up of the random stacking of single or few layers. All these characters show that this delaminated mesoporous material meets the requirements for application as support in the hydrotreatment of heavy molecules.     

聚-γ-谷氨酸包覆介孔分子筛MCM-41控释体系研究

用硅酸酯水解法制备了孔径为3 nm的MCM-41作为烯效唑载体,采用负压浸渍法载药.用XRD、BET、TEM、SEM、TG等仪器对包覆体系进行了表征分析.用低平均分子量γ-PGA(M.W.≈9180 Da)包覆负载药物的纳米粒子,形成控释体系.在不同乙醇-PBSaq溶液中,对不同控释体系的控释效应进行了探究.通过零级释放、一级释放、Higuchi和Rigter-Peppas释放动力学模型的拟合探究控释体系的药物控释机理.分析结果表明：烯效唑在MCM-41外表面及孔道内均有吸附,负压浸渍法能有效促使烯效唑分子进入3 nm孔道内部,以单分子层的吸附为主;在聚乙烯亚胺作用下,制得包覆壳层厚度均一、分散性较好的MCM-41@γ-PGA纳米控释体系;未包覆的载药体系的药物释放不满足零级释放、一级释放和Higuchi模型,但满足Rigter-Peppas释放动力学模型,遵循Fick扩散机理.     

无机硬模板HMS制备介孔碳工艺

以硅基介孔材料HMS(hexagonal mesoporous silica)为硬模板,以蔗糖为碳源,通过在N2气氛下高温碳化蔗糖,并利用氢氟酸除去模板制成介孔碳.分析了蔗糖填充方法、碳化温度和蔗糖与HMS的质量比对产品介孔碳结构的影响,并利用X衍射衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、低温氮吸附-脱附及傅里叶红外(FT-IR)对样品进行了表征.结果表明,将一定量的蔗糖分两步填入HMS介孔中有利于碳源在模板孔道中均匀分布,有助于有序介孔碳的形成;碳化温度对最终产品碳的结构影响显著,适宜的碳化温度为800℃;蔗糖与HMS的质量比也直接影响产品的结构,两者的质量比过高或过低均难以形成介孔碳,最优比例为1.300∶1;所制成的介孔碳具有蠕虫状结构,比表面积可达2433m2/g.     

Diffusion effects on formation process of mesoporous molecular sieve MCM-41

The regular mesoporous molecular sieve MCM-41 has been investigated at different stages during its formation,using high resolution transmission electron microscopy and powder X-ray diffraction.The results not only support the liquid-crystal templating mechanism previously postulated,but allow the extension fo its scope to discribe ditails of MCM-41 formation.It has been observed that formation of the hexagonal liquid crystal phase on the one hand and of silica aggregates on the other,occurs simultaneously at the inception of gel formation and throughout the crystallisation.This process is most probably affected by diffusion of both the surfactant molecules and the oligomeric silicate ions.With this postulate it becomes possible to explain several experimental observation(both old and new)and to develop a multi-step synthesis method to grow large particles of MCM-41 using small calcined crystals of MCM-41 as seeds.     

三维有序介孔镍铁磷化物的制备及电解水析氢性能研究

利用三维SiO₂纳米球阵列作为介孔模板,通过高温磷化合成了不同镍与铁物质的量比的三维有序介孔镍铁磷化物(3DOM Ni_XFe_1-XP);利用透射电子显微镜(TEM)、氮气吸脱附测试(BET)、X射线衍射(XRD)、X射线光电子能谱(XPS)等物理表征方法对所制备材料的形貌和结构进行分析,并通过电化学测试在0.5 mol/L H₂SO₄中系统评价了其电解水析氢(HER)性能。结果表明：3DOM Ni_XFe_1-XP成功地反向复制了SiO₂模板的有序介孔结构,孔道之间排列整齐且相互连通;随着Fe含量的增加,3DOM Ni_XFe_1-XP的HER性能呈现先升高后下降的趋势,在Ni与Fe物质的量比为7∶3时HER性能达到最优;当电流密度达到10 mA/cm²时,3DOM Ni_0.7Fe_0.3P所需过电位为132 mV...     

有序介孔金属氧化物的合成及其光催化性能表征

以钛酸异丙酯[Ti(OCH(CH3)2)4]、正硅酸四乙酯[Si(OC2H5)4,TEOS]、钽酸乙酯[Ta(OC2H5)5]、铌酸乙酯[Nb(OC2H5)5]为原料,采用溶胶-凝胶法成功合成了80TiO2.20SiO2和TaNbO5复合介孔分子筛.XRD表征结果表明,新合成样品的介观结构皆具有高的有序度;550℃焙烧去除模板剂后,仍保持良好的有序度.在焙烧过程中80TiO2.20SiO2骨架内有锐钛矿纳米晶粒产生,而TaNbO5仍保持无定形相.在紫外光照射下,介孔80TiO2.20SiO2和TaNbO5对分解H2S气体皆表现出高的光催化活性.介孔80TiO2.20SiO2分解H2S的活性是无孔80TiO2.20SiO2的近16倍.     

酰胺基改性的介孔MCM-41锚定Cu(Ⅱ)杂化材料的合成和表征

利用介孔分子筛MCM－41内孔壁表面的硅羟基，成功地将酰胺基团嫁接天介孔材料的孔壁上，并通过该官能团与铜离子形成配位键，合成了Cu(Ⅱ）复合物修饰的MCM－41新材料。通过XRD、BET、SEM－EDX、ICP和TG等手段对该杂化材料进行了表征。结果表明，修饰过的MCM－41的有序度降低，比表面积和孔容都有所下降；而铜离子均匀分布在有机－无机杂化材料中。