微型多孔材料
介孔材料
吸附
材料科学
吸附
化学工程
介孔二氧化硅
多孔性
化学
有机化学
复合材料
催化作用
工程类
作者
J.M. Esparza,M.L. Ojeda,A. Campero,Gerardo Aguirre,Carlos Felipe,M. Asomoza,Salomón Cordero-Sánchez,Isaac Kornhauser,Fernando Rojas
出处
期刊:Journal of Molecular Catalysis A-chemical
[Elsevier BV]
日期:2004-11-12
卷期号:228 (1-2): 97-110
被引量:53
标识
DOI:10.1016/j.molcata.2004.09.042
摘要
Mesoporous and microporous silica substrates, each of these kinds endowed with unique textural characteristics, have been prepared via sol–gel and micelle-templating techniques and characterized through N2 sorption. Materials consisting of a lattice of cage-like monodisperse cavities interconnected by narrow throats (SBA-16), a set of individual cylindrical pores of about the same size (SBA-15), a network of long sinuous ganglion-like sequences of bulges and throats (mesoporous glass, MG), or microporous arrangements of globular nanoparticles (microporous SiO2) have been developed. The N2 sorption isotherms of microporous silica at 76 K correspond to International Union of Pure and Applied Chemistry (IUPAC) type I, while those of mesoporous SBA-16, SBA-15, and MG silica match a type IV with hysteresis loops of types H1 or H2 depending on the regularity and nature of the void elements constituting the substrate. A characteristic common to all kinds of porous SiO2 solids herein synthesized is the rigidity of the arrangements, since the total pore volumes attain limiting values. Pore-size distributions of mesoporous SiO2 materials can be calculated by density functional theory (DFT) and sometimes by Barrett–Joyner–Halenda (BJH) methods. The microporous SiO2 adsorbent depicts a larger amount of big micropores (supermicropores) rather than small micropores (ultramicropores), this being a very useful characteristic for the entrapment and ulterior release of volatile compounds. MG substrates depict a percolation vapor threshold while the SBA-16 material shows a cavitation phenomenon during capillary evaporation. Additional properties of SBA-16, SBA-15, MG silica substrates are studied via primary desorption scanning curves.
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