ABC triblock copolymer-stabilized gold nanoparticles for catalytic reduction of 4-nitrophenol

• PEG–PEI–PCL-stabilized sub-10 nm gold nanoparticles (AuNPs) were prepared in an aqueous medium.
• The fabrication route is very mild, convenient, and reproducible.
• PEG–PEI–PCL-stabilized AuNPs have high catalytic activity for the reduction of 4-NP by NaBH4 in aqueous solution.
• ABC triblock copolymer PEG–PEI–PCL as the AuNP stabilizer has significant advantages in stability and catalytic activity.

Gold nanoparticles (AuNPs) with particle size below 10 nm exhibit high catalytic activity for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). However, AuNPs are unstable in aqueous solution or an organic solvent in the absence of a stabilizer and a dispersion agent. In this study, we prepared highly dispersed AuNPs using the ABC triblock copolymer poly(ethylene glycol)–block-linear polyethylenimine–block-poly(ε-caprolactone) (PEG–PEI–PCL) as the stabilizer for the first time. The preparation route is very mild, convenient, and reproducible. The mean diameter of AuNPs is approximately 8 nm with a normal distribution. The as-prepared PEG–PEI–PCL-stabilized AuNPs have high catalytic activity for the reduction of 4-NP by sodium borohydride (NaBH4) in aqueous solution. Compared with AB diblock copolymer PEG–PEI, ABC triblock copolymer PEG–PEI–PCL as the AuNPs stabilizer has significant advantages in stability and catalytic activity.

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