Method for preparing mesoporous silica spherical nanoparticles

Abstract

The invention discloses a method for preparing mesoporous silica spherical nanoparticles. According to the method, the used template agent refers to cetyl trimethyl ammonium bromide, the alkali source refers to an organic small molecule amine, the silicon source refers to tetraethyl orthosilicate (TEOS), and the organic alcohol salt serves as a promoter. According to the molar composition of the raw materials, a ratio of the silicon source to the cetyl trimethyl ammonium bromide to organic alkali to sodium methylate to water is (1):(0.03-00.06):(0.5-2):(0.001-0.5):(80-500). Accurate synthesis in the particle size range of 25-50nm is realized by regulating the amount of the organic alcohol salt and regulating the nucleation rate of particles. Compared with the prior art, the method disclosed by the invention has the most significant advantage that the hydrolysis and condensation rate of the silicon source is promoted by taking the organic alcohol salt with high nucleophilicity as the promoter. Therefore, the silicon source is subjected to burst nucleation in a very short time, so that the small-size mesoporous silica spherical nanoparticles are prepared. The synthetic method disclosed by the invention is simple, short in cycle, low in cost and high in repeatability and is an environment-friendly green synthetic method.

Description

Technical field [0001] The invention relates to a preparation method of nano spherical mesoporous molecular sieve, in particular to a preparation method of silicon-based mesoporous molecular sieve nano particles with a particle size of 50 nm. Background technique [0002] Mesoporous silica nanomaterial is a new type of inorganic nanomaterial with high specific surface area, large pore volume, morphology and size controllable. In recent years, its application research in the fields of materials science, biomedicine, environmental protection, and biosensors has caused Received widespread attention. On the one hand, due to its low toxicity and easy elimination, it has become more and more widely used in drug slow-release and biological applications; on the other hand, in the use of solar energy, it has a smaller refractive index and more pores. , Is a good anti-reflective (AR) material; but both of these applications require its size to be below 50nm, so the macro-quantitative and ...

AI Technical Summary

Problems solved by technology

The current main synthetic strategies for the synthesis of small-sized mesoporous silica nanoparticles (MSNs) include: using a single CTAB cationic surfactant (Angew. Chem. Int. Ed., 2002, 2151, 2317.), in the early stage of the reaction, By diluting with a large amount of water, the particle growth has been quenched, thereby preparing mesoporous silica nanoparticles with a size of less than 100 nm, but the shape of the particles is irregular, and the size distribution is very inhomogeneous; by the improved Stöber method (J. Phys . Chem. B 2004, 108, 20122.), using ethanol as a co-surfactant of CTAB cationic surfactant can prepare highly monodisperse mesoporous SiO 2 nanoparticles, but often larger than 100 nm in size; Bein by using triethanolamine (TEAH 3 ) to replace inorganic bases to synthesize mesoporous nanoparticles with a size of less than 200 nm (Adv. Funct. Mater. 2007, 17, 605.), but triethanolamine (TEAH 3 ) is used in a large amount, and high-speed centrifugation is required to obtain the final particles; Kuroda recently reported a new synthesis strategy to prepare mesoporous SiO with a size smaller than 50nm 2 Nanoparticles, but the molar ratio of CTAB / TMOS is greater than 0.5, the amount of water used is extremely high, the cost of synthesis is extremely high and the surfactant can only be removed through a complicated dialysis process (Chem. Commu., 2009, 5094.); China Patent CN1923684A uses sodium lauryl sarcosinate as a template and (3-aminopropyl)trimethoxysilane as a co-structure directing agent to synthesize SiO with uniform size and controllable size 2 Nanoparticles, but the cost of synthesis is relatively high; the synthesis strategy of mixed templates can also be used to synthesize highly monodisperse mesoporous nanoparticles, but the expensive price of surfactants limits its wide application (Chemical Journal of Chinese Universities, 2011, 32, 560.)

From the perspective of particle nucleation and growth, according to the classic Lamer's law, if small-sized silica nanoparticles are synthesized, the hydrolysis rate of the silicon source should be as fast as possible, and a large number of silica sub-nanometer nuclei will be formed in a short period of time. Therefore, tetramethoxysilicate (TMOS) is the most ideal silicon source, but the silicon source is not only expensive but also easily hydrolyzed in the air and difficult to preserve for a long time, thus limiting its use as a silicon source in mesoporous silica nanometers. Use in Particle Synthesis

It can be seen from the above reports that the existing synthetic methods have disadvantages such as harsh conditions, high cost, heavy pollution, and unfavorable for large-scale production.

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