Controllable Preparation of Thiol-Modified Silica Particles by an Optimized Stöber Method

This study delves into the impact of the hydrolysis/condensation of 3-mercaptopropyltrimethoxysilane (MPTMS) on the modification of thiol groups on the surface of silica particles. By employing an optimized Stöber method, such as the pH, water content, and quantity of MPTMS in the reaction system, a systematic exploration of the size, shape, and size/shape distribution of the thiol-modified silica particles was carried out. During these investigations, Ellman's colorimetric method and Raman spectroscopy were utilized to quantitatively analyze the changes in the amount of thiol modification on the surface of silica particles. Furthermore, the synthesized SH-SiO₂ particles were employed as adsorption carriers for Au³⁺ ions, which were then reduced to form SH-SiO₂/Au composite particles. Significantly, these prepared SH-SiO₂/Au composite particles exhibited remarkable catalytic activity in the reduction reaction of p-nitroaniline.