Structural change of mesoporous silica with sonochemically prepared gold nanoparticles in its pores

Ultrasonic irradiation of mesoporous silica soaked in a mixture of chloroau ric acid and isopropanol for 120 min in Ar atmosphere at room temperature y ielded Au/SiO2 mesoporous composite., which was characterized by high resol ution transmission electron microscopy and optical absorption measurement. The structure of mesoporous silica after sonochemical preparation of gold ( Au) nanoparticles within its pores was studied by nitrogen adsorption techn ique. It has been shown that the structural parameters, such as specific su rface area (SSA), porosity (P), the mean pore diameter (l(p)) were increase d significantly after ultrasonic irradiation. It is suggested that the coll ision of An nanoparticles with pore walls and localized erosion induced by the asymmetric implosive collapse of cavities on the extensive liquid-solid interface that are responsible for the structural change in the mesoporous solid. (C) 2001 Elsevier Science B.V. All rights reserved.