Preparation and properties of silica-gold core-shell particles

作者：Choma Jerzy; Dziura Aleksandra; Jamiola Dominik; Nyga Piotr; Jaroniec Mietek^*

来源：Colloids and Surfaces A: Physicochemical and Engineering Aspects , 2011, 373(1-3): 167-171.

DOI：10.1016/j.colsurfa.2010.10.046

• Silica-gold core-shell particles
• Modification of silica particles
• Deposition of colloidal gold
• Reduction of tetrachloroauric acid

Silica-metal core-shell particles, as for instance those having siliceous core and nanostructured gold shell. attracted a lot of attention because of their unique properties resulting from combination of mechanical and thermal stability of silica and magnetic, electric, optical and catalytic properties of metal nanocrystals such as gold, silver, platinum and palladium. Often, the shell of the core-shell particles consists of a large number of metal nanoparticles deposited on the surface of relatively large silica particles, which is the case considered in this work. Namely, silica particles having size of about 600nm were subjected to surface modification with 3-aminopropyltrimethoxysilane. This modification altered the surface properties of silica particles, which was demonstrated by low pressure nitrogen adsorption at -196 degrees C. Next, gold nanoparticles were deposited on the surface of aminopropyl-modified silica particles using two strategies: (i) direct deposition of gold nanoparticles having size of about 10 nm, and (ii) formation of gold nanoparticles by adsorption of tetrachloroauric acid on aminopropyl groups followed by its reduction with formaldehyde.
The overall morphology of silica-gold particles and the distribution of gold nanoparticles on the surface of modified silica colloids were characterized by scanning electron microscopy. It was shown that direct deposition of colloidal gold on the surface of large silica particles gives more regular distribution of gold nanopartciles than that obtained by reduction of tetrachloroauric acid. In the latter case the gold layer consists of larger nanoparticles (size of about 50 nm) and is less regular. Note that both deposition strategies afforded silica-gold particles having siliceous cores covered with shells consisting of gold nanoparticles of tunable concentration.

• 出版日期2011-1-3