以十二烷基三甲基溴化铵为模板制备高度有序的介孔二氧化硅材料

Synthesis of Highly Ordered Mesoporous Silica Materials Using Decyltrimethylammonium Bromide as a Template

以长碳链阳离子表面活性剂如十六烷基三甲基溴化铵为模板,可制得高度有序的介孔二氧化硅材料,而碳链较短的表面活性剂如十二烷基三甲基溴化铵,由于其表面活性较差,以其为模板难以制得有序介孔二氧化硅材料。以十二烷基三甲基溴化铵为模板剂,考察了不同硅源、碱源以及pH值对介孔材料结构的影响,采用XRD、FTIR、SEM、HRTEM和N2物理吸附等手段分别对产物的晶体结构、织构性质、形貌和孔道结构进行表征。结果表明,以正硅酸乙酯为硅源,在有机碱四甲基氢氧化铵存在下,以十二烷基三甲基溴化铵为模板,制得了具有规整六方结构的高度有序介孔二氧化硅材料,其孔径和晶胞常数分别为2.25 nm和3.72 nm。

The preparation of highly ordered mesoporous silica materials with the long-chain surfactant cetyltrimethylammonium bromide is relatively easy,while a shorter carbon chain surfactant such as dodecyltrimethylammonium bromide(DTAB),due to its poor surface activity,is difficult to be used to prepare highly ordered mesoporous silica materials.Here,mesoporous materials were synthesized by using dodecyltrimethylammonium bromide as templates.The effects of different silica sources,alkali sources and pH value on the structure of mesoporous materials were investigated.The crystal structure,texture properties,surface morphology and pore structure of the obtained products were characterized by XRD,FTIR,SEM,HRTEM and N2 adsorption-desorption.The results show that highly ordered mesoporous silica materials with hexagonal structure are prepared by using DTAB as a template and in the presence of TMAOH organic alkaline.The pore size and unit cell parameter of the obtained sample are 2.25 nm and 3.72 nm,respectively.