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Synthesis of Mesoporous Silica with Controlled Morphology and the Regulation of Nanochannel Direction of Mesopores

Author: ZhangAnFeng
Tutor: GuoXinWen；ZhangYongChun
School: Dalian University of Technology
Course: Industrial Catalysis
Keywords: Silica hollow spheres Silicon Nanotubes Mesopores direction Anodic alumina membranes A polycarbonate film
CLC: O613.72
Type: PhD thesis
Year: 2010
Downloads: 734
Quote: 1
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Abstract

Since 1992, Mobil Corporation discovered M41s since ordered mesoporous material due to the adsorption, separation, catalysis has important application value and become a focus of research is one; while the morphology of mesoporous materials, size, pore size, mesopores and other functions of the control and direction of its application has an important impact. This thesis by oil - liquid interface and solid - liquid interface synthesis of mesoporous silica specific morphology of the mesopores control of the direction of a more in-depth research, the main contents are as follows: TEOS as the silicon source, P123 mesoporous template agent, benzene microemulsion droplets hollow balls nuclear template by sol - gel method, benzene - water, oil - liquid interface, hydrothermal synthesis of mesoporous channels along Trail the vertical penetration of the silica shell hollow spheres. Study found that benzene P123 micelles role of initial orientation along the radial distribution of mesopores reasons; shell on the mesopores are interconnected; mesoporous silica hollow spheres as hard templates, furfuryl alcohol as carbon precursor body, alcohol polymerization catalyst of oxalic acid, by the casting method nano synthesized mesoporous carbon hollow spheres. Through the sub-heading towards anodic alumina membranes (AAO) within the pores of adding TEOS acid solution with P123, P123 makes TEOS acid solution with the inner wall of the AAO pore hierarchical distribution and hydrolysis, polymerization, since assembled in the AAO pore solid reactants - liquid interface synthesized mesoporous channels perpendicular to penetrate the wall of the silicon nanotubes; their morphology depends AAO pore structure, the wall of mesoporous pore size of about 10 nm , planar hexagonal arrangement. Study found that the adsorption on the channel walls in the AAO TEOS hydrolysis of the acid solution with the P123 sol volume, is to determine the silicon nano-tube wall causes mesopores direction: When the silica sol generated wall nanotubes Less than two mesopores repeat cycle, mesopores vertical through-silicon nanotube wall, the wall thickness of about 15 nm; when the wall thickness greater than 2 mesopores repeat cycle, mesopores surround the tube axis or parallel to the tube axis, the wall thickness of about 40-60 nm. Vertical channels in the synthesis of mesoporous silicon through-wall nanotubes process, the silicon source, adding additives benzene, can expand the tube wall to the 15nm diameter mesopores, at which point the ordered mesoporous decreased. Found changes with the P123 TEOS AAO pores acid solution is added to the sequence, by suction AAO membrane pores adjust the molar ratio of the reactants, the same can be synthesized with different directions mesopores silicon nanotubes, However, the ordered mesoporous decreased. P123 TEOS acid solution in the pre-SBA-15 formed by hydrolysis AAO pore precursor in the reaction, can be synthesized mesoporous channels perpendicular to the direction of the dense SiO2-AAO film composite membrane; AAO film dissolved in hydrochloric acid to obtain a dielectric Kong Kong Daoping row axis of SBA-15 nanowires. Pore ??polycarbonate membrane on the inner wall can also be synthesized mesoporous channels perpendicular to penetrate the wall of silicon nano-tubes. By modulating the pore diameter polycarbonate membrane having different diameters can be synthesized silicon nanotubes were 200,100 and 50nm. Since the curvature of pore polycarbonate membrane, the walls of mesoporous silicon nano tube diameter decreases as the degree of order is reduced gradually from flat irregular hexagonal arrangement tendency.

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