Synthesis of well-dispersed nanoparticles within porous solid structures using surface-tethered surfactants in supercritical CO2

Abstract

We have developed a new method for the synthesis of Pd nanoparticles with controllable sizes within a silica matrix using solid-supported surfactants in supercritical CO₂. XRD, HRTEM and CO chemisorption data show that unformly sized Pd nanoparticles are evenly distributed within the porous silica and are chemically tethered by surfactant molecules [poly(oxyethylene stearyl ether) and fluorinated poly(oxyethylene)]. It is postulated that tiny solid-supported surfactant assemblies act as nano-reactors for the template synthesis of nanoparticles or clusters from the soluble precursors therein.