One-pot synthesis of gold nanoparticle functionalised mesoporous silica – The double role of a tri-block copolymer and chitosan

Abstract

A nonionic tri-block copolymer (Pluronic P123) and a cationic polysaccharide (chitosan) were compared as reduction and structure directing agents during in situ synthesis of gold functionalised mesoporous silica materials. The tri-block copolymer syntheses resulted in hexagonally ordered pore structures with cagelike pores present in open-ended tubular pore systems, but provided less control of the growth of gold nanoparticles. The chitosan syntheses, on the other hand, gave better control of the particle growth (i.e. smaller gold particles), but no pore ordering and lower porosity were obtained. Also in this case, however, cagelike pores were present in interconnected pore systems. In both approaches at least some of the gold particles are present in the cagelike pores of the materials. The functionalised structures were characterised using nitrogen physisorption, powder X-ray diffraction, X-ray fluorescence spectroscopy, transmission electron microscopy and UV–Vis spectroscopy.