One-pot synthesis of Au-M@SiO(2) (M = Rh, Pd, Ir, Pt) core–shell nanoparticles as highly efficient catalysts for the reduction of 4-nitrophenol

The conversion of p-nitrophenol (4-NP) to p-aminophenol (4-AP) is of great significance for pharmaceutical and material manufacturing. In this work, Au-M@SiO(2) (M = Rh, Pd, Ir, Pt) nanoparticles (NPs) with core–shell structures, which are expected to be excellent catalysts for the transformation of 4-NP to 4-AP, were synthesized by a facile one-pot one-step method. The structure and composition of the NPs were characterized through transmission electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. Au-M@SiO(2) (M = Rh, Pd, Ir, Pt) core–shell NPs showed excellent catalytic activity in the reduction of 4-NP, which is superior to most catalysts reported in the previous literature. The enhanced catalytic activity of Au-M@SiO(2) core–shell NPs is presumably related to the bimetallic synergistic effect. This study provides a simple strategy to synthesize core–shell bimetallic NPs for catalytic applications.