一步法合成载铁有序介孔碳材料的形成机理

摘要

采用软模板路线以三嵌段共聚物F127为模板剂,间苯二酚-甲醛缩聚所形成酚醛树脂（RF）为碳源,与酚羟基有络合作用的无机铁盐为金属前体,在无外加酸碱催化剂的条件下,利用铁盐的水解反应形成酚醛缩聚所需酸性环境,多组分共组装一步合成了载铁有序介孔碳材料（Fe/OMC）。对Fe/OMC合成各阶段过程进行了分析,利用X射线衍射、透射电子显微镜等手段对材料进行表征,比较了不同老化时间、硝酸铁投加量及酚醛比例等合成条件对材料结构的影响规律。结果表明,在较长的老化时间（≥60 h）、适宜的n（Fe）/n（R）比（0.05～0.2）和n（R）/n（F）比[（1/1.5）～（1/2）]条件下,均可形成有序的介孔结构。在此基础上,提出了载铁有序介孔碳材料的形成机理。%Ordered Fe-containing mesoporous carbon composite materials（Fe/OMC）have been synthesized via soft-templating routes by using triblock copolymer F127 as a template agent,resorcinol（R）-formaldehyde（F）as a carbon precursor,inorganic iron salts having complex reaction with phenols as a metal precursor in one-pot.The main strategy of this approach was to utilize the acidity self-generated from the hydrolysis of inorganic salts in the aqueous solutions as the catalyst for RF polymerization,where no addition of mineral acids was necessary.The resultant Fe/OMC materials were characterized by X-ray diffraction,Transmission electron microscopy.The influences of the aging time,the dosage of iron nitrate and the molar ratio of R/F on the structure of the obtained materials were investigated.Results show that the ordered mesoporous structure can be obtained under the synthetic condition of the aging time≥60 h,n（Fe）/n（R）=0.05— 0.2,n（R）/n（F）=1/1.5— 1/2.0.Moreover,a possible mechanism of the synthesis of Fe/OMC was proposed.