含铁MCM-41的合成与表征

实验采用液相沉积方式，向MCM-41有序介孔微球的介孔中引入铁盐，通过加热使铁盐分解，铁以氧化物纳米颗粒或Fe-O纳米团簇的形式存在于有序介孔微球的介孔中,从而获得含铁MCM-41有序介孔微球.对不同铁含量的MCM-41进行了比较性表征，并研究了不同铁源对含铁MCM-41合成的影响.研究表明，以Fe(acac)₃的甲苯溶液和Fe(NO₃)₃的水溶液为铁源时，所得试样中铁的含量均随铁离子浓度的增大而增大.铁离子浓度相同时，由前者所得试样的载铁量是后者的3～4倍，最大铁负载量达1 mmol•g^-1.载铁后，有序介孔微球的比表面积、孔容和孔径均减小.以Fe(NO₃)₃的水溶液为铁源时，载铁前驱体试样煅烧后，MCM-41的硅氧骨架发生收缩，而以Fe(acac)₃的甲苯溶液为铁源时，MCM-41的硅氧骨架未见变化.因此，从载铁量及负载过程对有序介孔材料骨架结构的影响看，Fe(acac)₃的甲苯溶液作为铁源用于合成含铁MCM-41优于Fe(NO₃)₃的水溶液.

Syntheses and characterizations of iron-containing MCM-41

Using the incipient wetness impregnation procedure, iron was loaded in the mesopores in MCM-41 microspheres.The hybrid microspheres were decomposed by heating，producing iron-containing MCM-41 spheres with nano iron-oxygen clusters or nano-sized iron oxide particles inside the mesopores. Comparative characterizations of the iron-containing MCM-41 with different iron contents was performed.The influence of iron source on the synthesis of iron-containing MCM-41 was studied.The samples loaded with iron acetylacetonate have 3—4 times of iron content than those loaded with iron nitrate. The highest iron confent in MCM-41 was 1 mmol•g-1.The specific surface area,pore volume and pore size of the MCM-41 microspheres decreased after iron loading.In the case of loading with iron nitrate, contraction of the MCM-41 skeleton was observed after calcination, but no similar change in the case of loading with iron acetylacetonate. As far as the iron-loading content and the influence of the iron-loading on the skeleton of the mesoporous material were concerned, toluene solution of iron acetylacetonate was superior to the aqueous solution of iron nitrate as iron source for the synthesis of iron-containing MCM-41.