期刊
MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS
卷 20, 期 6, 页码 1461-1469出版社
UNIV FED SAO CARLOS, DEPT ENGENHARIA MATERIALS
DOI: 10.1590/1980-5373-MR-2016-1064
关键词
MCM-41; Al-MCM-41; non-hydrothermal method; alkali-free system
资金
- CNPq
- CAPES (Ciencias sem Fronteiras)
Purely siliceous MCM-41 and Al-containing MCM-41 (Al-MCM-41) mesoporous materials were synthesized by non-hydrothermal method in alkali-free ions medium at room temperature and short reaction times. Under these synthesis conditions, it was also investigated the influence of Al incorporation in the crystal structure of MCM-41. The solids were characterized by ICP-OES, AAS, N-2 adsorption at 77 K, XRD, TEM, NH3-TPD, Al-27 and Si-29-MAS-NMR, FT-IR and TGA. The resulting mesoporous materials showed a well-defined hexagonally ordered pore geometry maintaining a uniform and unimodal pore size distribution with high specific surface areas (1000-1400 m(2)g(-1)). The Al+3 ions were introduced successfully in the structure of the purely siliceous MCM-41 expanding the unit cell parameter and forming four-coordinated Al species, and in a less extent, forming six-coordinated Al species. In addition, the surface acidity of the MCM-41 increased with Al loading. Contrary, the presence of Al in the MCM-41 mesoporous structure resulted in a decrease of the crystallinity and specific surface area possibly due to the presence of Al species in highly distorted tetrahedral structures and Al extra-framework or amorphous alumina occluded in the pores. The MCM-41 type mesoporous materials obtained in this work show similar characteristics of those synthesized by conventional hydrothermal methods.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据