Inverse miniemulsion-based preparation of raspberry-like Au/SiO2 nanocomposite particles with high catalytic activity towards reduction of p-nitrophenol

• A convenient method based on the inverse miniemulsion technique was proposed to prepare raspberry-like Au/SiO2 nanocomposite particles (NCPs).
• Most of Au nanoparticles were half-embedded in the porous SiO2 nano-supports, offering a good morphological stability to the Au/SiO2 NCPs.
• Formation mechanism of raspberry-like Au/SiO2 NCPs was discussed.
• The Au/SiO2 NCPs displayed a good catalytic activity and recycling performance towards reduction of p-nitrophenol.

A convenient method based on the inverse miniemulsion technique was proposed to prepare raspberry-like Au/SiO2 nanocomposite particles (NCPs). HAuCl4 was incorporated into porous SiO2 nano-supports through a sol–gel process of a silica precursor in inverse miniemulsions. Raspberry-like Au/SiO2 NCPs were subsequently obtained through in situ reduction of the incorporated HAuCl4 by hydrazine at the surface of SiO2 nano-supports. Most of Au nanoparticles (NPs) were half-embedded in the SiO2 nano-supports and were covered by a thin layer of porous SiO2, offering a good morphological stability to the Au/SiO2 NCPs. The content of Au NPs of the Au/SiO2 NCPs could be adjusted by the loading of HAuCl4. The influences of the HAuCl4 loading on the particle size and particle morphology of the Au/SiO2 NCPs, the pore properties of the SiO2 nano-supports, as well as the properties of the Au NPs were systematically investigated. The formation mechanism of the raspberry-like Au/SiO2 NCPs was discussed. All the synthesized Au/SiO2 NCPs displayed a high catalytic activity towards the reduction of p-nitrophenol.

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