甲醇对有序介孔氧化硅结构和形貌的影响

Effect of the Methanol on Structure and Morphology of Ordered Mesoporous Silica

以三嵌段共聚物P123为模板剂、正硅酸乙酯TEOS为无机硅源,采用水热法合成了SBA-15介孔分子筛,并采用XRD、SEM、TEM、N2吸附-脱附等表征手段研究了不同含量的甲醇对SBA-15分子筛的结构与形貌的影响。结果表明:甲醇对SBA-15介孔材料的形貌与结构影响较大,随着甲醇含量的增加,SBA-15介孔分子筛逐渐从纤维状变为球形,且在很宽的浓度范围内存在一个纤维状与球形共存的中间态,这主要是由于亲水性小分子的嵌入导致双胶束的形成,并最终形成两种形貌的共存;同时,随着甲醇含量的增加,介孔由有序向无序状态变化,N2吸附-脱附实验表明平均孔径逐渐从10.2nm降低到8.8nm,孔径的分布逐渐变宽,孔容由1.003cm3/g逐渐增加到2.708cm3/g,比表面积由455.3m2/g增加到1063m2/g,说明随着甲醇添加量的增加,介孔逐渐向微孔方向扩展。

Ordered mesoporous molecular sieve SBA-15 was synthesized by hydrothermal reaction with TEOS as the source of inorganic silica and triblock copolymer P123 as the template in strong acid media. Microstructure and morphology of the sample were characterized by XRD, SEM, TEM and N2 adsorption/desorption isotherm. The results show that the fibre was gradually evolved to sphere in a wide range of concentration of P123 surfactant and formed coexistence of two morphologies when methanol was added to the solution, which resulted from embedding of small molecules methanol. N2 adsorption/desorption shows that average pore size decreases from 10.2 nm to 8.8 nm, however, pore volume and surface area increase from 1.003 to 2.708 cm^3/g and from 455.3 to 1063 m^2/g, respectively, indicating that the increase of mieropores.