ONE-STEP SYNTHESIS OF GOLD NANOPARTICLES STABILIZED IN ACIDACTIVATED MONTMORILLONITE FOR NITROPHENOL REDUCTION

Gold nanoparticles were prepared by one-step using chemical reduction from HAuCl4.3H2O gold precursor by sodium borohydride (NaBH4) in presence of acid-activated montmorillonite us stabilizer. The obtained gold nanoparticles stabilized in montmorillonite (Au°-montmorillonite) were used as catalysts for reduction of 4-nitrophenol to aminophenol with sodium borohydride at room temperature. Different techniques (UV-Vis spectroscopy, XRD, TEM and N2 adsorption) were used to characterize gold nanoparticles. The UVVis results confirmed directly the gold nanaoparticles formation. The XRD, N2 adsorption and MET results was also confirmed the formation of gold nanoparticles in the pores of montmorillonite with an average size of 5.7nm with uniform distribution. The reduction reaction of 4-nitrophenol into 4-aminophenol with NaBH4 catalyzed by Au°-montmorillonite catalyst exhibits remarkably a high activity; the reaction was completed within 4.5min.