介孔锰氧复合物的表面活性剂模板合成与孔结构分析

Surfactant-template synthesis and pore structure study of mesoporous manganese oxides

锰氧复合物以其在电化学与催化等领域的众多应用而得到研究者的广泛关注。采用非离子表面活性剂(脂肪醇聚氧乙烯醚,AEO9)模板与溶胶凝胶反应相结合,制备了平均孔径在5 0nm、BET比表面积为387m2/g和热稳定性良好的介孔锰氧复合物。高分辨率透射电镜的直接观察发现该材料由大量有序排列的层状微晶构成,这不同于文献中类似溶胶-凝胶方法合成所得的非晶态氧化锰材料的结果。同时根据N2吸脱附等温线类型与物理吸附理论对材料的孔结构进行了简单解释。采用该方法制备的介孔材料总孔体积与合成中表面活性剂用量呈线性关系,表明AEO9在材料制备中是起模板构筑作用的。

Much attention has been focused on the synthesis and applications of manganese oxides in electrochemistry and catalysis.A kind of mesoporous manganese oxide presented in this work has been synthesized by using nonionic surfactant (polyoxyethylene fatty alcohol,AEO9)-template and sol-gel method.The BET specific surface area of the material is 387 m2/g,and its average pore diameter is 50 nm.Discussion of the pore structure was also involved through the analysis of N2 adsorption-desorption isotherm and physi-adsorption theory.The direct observation of high-resolution transmission electron microscopy(HRTEM)indicates that the material in pseudo-crystalline with complex network pore structure,these are quite different with the amorphous manganese oxides prepared in the same sol-gel pathway.The material shows good thermal stability.The commulative pore volume of the mesoporous material increases linearly with the AEO9 extent used in synthesis,this indicates that surfactant aggregates work as template in the preparation.