High yield synthesis of branched gold nanoparticles as excellent catalysts for the reduction of nitroarenes

Abstract

A one-pot preparation of branched gold nanoparticles (NPs) in aqueous solution using acetanilide as both a reducing and shape-directing agent has been achieved. The structure, morphology and optical properties of the branched gold NPs can be tuned by controlling the concentration of acetanilide. In contrast to reported protocols, high quality and stable branched gold NPs can be produced exclusively without any sophisticated purification techniques. More interestingly, the gold NPs thus obtained are predominantly enriched with a uniform facet of {111}, as confirmed by HRTEM and XRD methods. When compared to reported gold NPs, the branched gold NP catalysts exhibited two to three orders of magnitude higher activity for the reduction of 4-nitrophenol into 4-aminophenol. Furthermore, the average turnover frequency of the branched gold NPs was found to be 19 molecules per min, which is significantly higher than that of spherical gold NPs and other reported branched gold NP catalyst systems.