One-step fabrication of gold nanoparticles-silica composites with enhanced catalytic activity

Abstract A fast and simple one-step method for the fabrication of stable gold nanoparticles-silica composites by using 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane(azacryptand) as a molecular anchor between nanoparticles and silica as well as reductant and stabilizer in the formation of the nanoparticles is reported. Gold nanoparticles-coated silica materials can be fabricated by mixing HAuCl 4 aqueous solution with the aqueous mixture of azacryptand and silica materials such as submicrometer silica particles and silica gel. The prepared nanoparticles-coated silica gel can effectively catalyze reduction of 4-nitrophenol by sodium borohydride in aqueous solution.