Method for preparing gold/titanium dioxide core-shell nanoparticle

Abstract

The invention discloses a method for preparing a core-shell nanoparticle which contains a noble metal core. The method comprises the following processing steps of: (1) preparing a carbon nanosphere which contains noble metal; (2) covering a shell on the outside of the carbon nanosphere which contains the noble metal; and (3) preparing the core-shell nanoparticle which contains the noble metal core. In the step (2), the shell is covered by dissolving the carbon nanosphere which contains the noble metal core in absolute ethyl alcohol, utilizing ammonia to control the hydrolytic speed of tetrabutyl titanate or ethyl orthosilicate, and reacting to obtain the shell covered on the outside of the carbon nanosphere which contains the noble metal. In the step (3), processes of slow heating and low-temperature preservation are adopted for calcination. According to the process, the ammonia is utilized to control the hydrolytic speed of the tetrabutyl titanate or the ethyl orthosilicate, and high-temperature backflow of an organic solvent is not needed so that reaction conditions are milder. The method has the advantages of simple process flow and suitability for industrial production. The noble metal core obtained by using the method has the advantages of uniform size, good granularity and integral shell structure.

Description

technical field [0001] The invention belongs to the field of material chemistry and nanometer materials, in particular to a preparation method of gold / titanium dioxide core-shell nanoparticle. Background technique [0002] With the in-depth development and application of nanotechnology, the synthesis of nanocomposite structures with multiple functions has become an important research focus and development trend in the field of nanoscience. The Yolk / Shell (core / shell) structure is a novel core-shell structure recently studied, which means that there are other particles in an empty shell and there is a gap between the two, and the Yolk / Shell structure The particles are free to move. The Yolk / Shell structure combines the properties of Yolk and Shell. The Shell part has characteristics such as low density and large specific surface area. At the same time, the nanoparticles (such as gold nanoparticles) in the Yolk part also have excellent properties, making them widely used in m...

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Problems solved by technology

Lee et al. [Angew.Chem.Int.Ed.50, 10208, (2011)] used silica as a template to first synthesize gold nanoparticles, then coat the silica shell, and then coat the silica shell The layer is covered with a titanium dioxide shell, and finally the silicon dioxide shell is selectively etched away by sodium hydroxide to obtain a gold / titanium dioxide yolk / shell structure, but this method has a complex synthesis process and a long production cycle; Park et al [Adv. Mater.Vol.20, 1523, (2008)] Utilize the reaction of gold and cyanide to first synthesize gold nanoparticles, coat the silica shell, and then use potassium cyanide to etch away part of the gold nanoparticles. Thus, a gold / silicon dioxide yolk / shell structure is obtained, but the synthesis cost of this method is high, and the etching degree of gold particles is not easy to control

Yu Shuhong et al [Chinese invention patent, application number is 200710023240.3] used carbon nanospheres containing gold particles to control the oil bath temperature and reflux time to obtain gold / titanium dioxide yolk / shell structures with different thickness shells, but the reaction system of this method For organic solvents such as ethylene glycol, the oil bath temperature is high, and the post-calcination temperature is also high

[0004] In summary, most of the current methods for preparing gold / titanium dioxide yolk / shell structures have complicated synthesis processes, long production cycles, and relatively harsh reaction conditions, and there are still great difficulties in the uniform particle size of gold nuclei and controllable morphology.

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