A simple approach to the synthesis of eccentric Au@SiO2 Janus nanostructures and their catalytic applications

•A simple approach was developed to synthesize Au@SiO2 Janus nanostructures.•The surface modification is critical to the preparation of Janus nanostructures.•The Janus nanostructures can be used to catalyze the reduction of 4-nitrophenol.

In this paper, we present a simple method to synthesize eccentric Au@SiO2 Janus nanoparticles. By simply tuning the concentration of poly(vinyl pyrrolidone) (PVP), the surface of gold nanoparticle can be partially or fully wrapped with the amphiphilic ligand. As a result, Janus nanoparticle or concentric core-shell nanostructures can be obtained, respectively. A systematic study has been carried out to confirm the function of PVP molecules. The as-prepared Janus nanoparticle can act as a catalyst to catalyze the reduction of 4-nitrophenol, while the core-shell nanostructure is not active due to the coverage of dense silica shell. This work provides a robust and scalable method to produce Au@SiO2 Janus nanoparticles.

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