Double Hydrophilic Block Copolymer Templated Au Nanoparticles with Enhanced Catalytic Activity toward Nitroarene Reduction

We present a facile method for synthesizing water-dispersible gold nanoparticles (Au NPs) using a double hydrophilic block copolymer (DHBC), poly(ethylene oxide)-block-poly(acrylic acid) (PEO-b-PAA), as a template and demonstrate their application in the reduction of nitroarenes. Selective coordinative interactions between a gold precursor and the PAA block of the DHBC lead to the formation of micelles, which are subsequently transformed into Au NPs with an average diameter of 10 nm using a reducing agent. The DHBC-templated Au NPs (Au@DHBC NPs) remain stable in water for several months without any noticeable aggregation. Furthermore, Au@DHBC NPs are found to be highly effective in catalyzing the reduction of a series of nitroarenes. Remarkably, the turnover frequency in the case of 4-nitrophenol using Au@DHBP NPs reaches 800 h–1, outperforming previously reported Au NP-based catalytic systems. We believe the enhanced catalytic activity is due to the DHBC shell around Au NPs, which templates the formation...