Preparation of Au catalysts supported on core-shell SiO2/polypyrrole composites with high catalytic performances in the reduction of 4-nitrophenol

Abstract In this paper, core-shell SiO 2 /polypyrrole (SiO 2 /PPy) composites were prepared via in situ chemical oxidation of pyrrole monomer on surface of the modified SiO 2 by using FeCl 3 as the oxidant. Au nanoparticles (NPs) were loaded on SiO 2 /PPy composites by means of the redox reaction between PPy and gold ions. Several analytical tools, such as TEM, FT-IR, XRD and EDX, were employed to characterize the morphology and structure of the as-prepared SiO 2 /PPy/Au composites. Their catalytic performances in reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with NaBH 4 as the reducing agent were studied. Results showed that the conversion of 4-NP was increased with an decrease of Au loading. The reduction of trace AuCl 4 − ions in core-shell composites to small Au NPs by NaBH 4 in the beginning of the reaction favored the enhancement of catalytic activity.