以硅酸钠为前驱物用间隔自组装法制备等级介孔二氧化硅

Preparation of Hierarchically Mesoporous Silicas via Partitioned Cooperative Self-assembly Using Sodium Silicate as Precursor

以硅酸钠为前驱物,以三嵌段共聚物(P123)为模板剂,用间隔自组装法(即PCSA法)制备了具有等级孔结构的介孔二氧化硅。结果表明:间隔条件等级孔结构的形成起到了关键作用,在加入量合适和间隔时间条件下间隔法允许在不使用添加剂、复合模板剂及特殊的制备条件下使用较廉价的硅酸钠制备有序的等级介孔二氧化硅。等级介孔二氧化硅的第一级介孔孔径约9 nm,第二级大孔径分布较宽,介于20-200 nm。而在特定的间隔条件下(SS6-4h-4.5与SS3-4h-7.5),可制备出第一级有序的等级介孔二氧化硅。

Hierarchically mesoporous silicas could be prepared by means of a previously reported partitioned cooperative self-assembly process(PCSA process) using nonionic triblock copolymer surfactant(P123) as template and sodium silicate as silica precursor. It was found that the partitioning conditions play a key role in inducing the formation of hierarchically mesoporous structures. Under suitable partitioning conditions, in terms of the amounts of sodium silicate in two partitioned additions and interval time between them, the PCSA process allows the preparation of hierarchically ordered mesoporous silicas based on cheap sodium silicate via such a simple templating system, without resorting to additives,multiple templates or complicated synthetic conditions. The size of the first series mesopores is around9 nm, while the second series of large pores possesses broadened pore size distributions ranging from20 nm to 200 nm. Under certain partitioning conditions(SS6-4h-4.5 and SS3-4h-7.5), hierarchically mesoporous silicas with the first series of ordered mesopores can be prepared.