β-Cyclodextrin polymer networks stabilized gold nanoparticle with superior catalytic activities

Support materials play a significant role in heterogeneous nanocatalysis.In this work,β-cyclodextrin(β-CD)was used directly as a monomer to construct polymer networks for gold nanoparticles(Au NPs)immobilization.Using the simple nucleophilic substitution reaction,β-CD based polymer networks(β-CDP-N andβ-CDP-C)were successfully prepared.Compared toβ-CDP-C,the hydroxyl groups and N atoms inβ-CDP-N played a synergistic role in immobilizing smaller Au NPs,thus leading to high catalytic activities.Notably,the apparent rate constant(Kapp)value for Au@β-CDP-N in the reduction of 4-nitrophenol to 4-aminophenol is 14.15×10^(-2)s^(-1),which shows a significant improvement over all previously reported Au NPs with solid supports under similar conditions.Considering the negligible porosity of theβ-CDP-N support,we purposed a"capture-catalysis-release"model to explain the high catalytic activity of Au@β-CDP-N.This explanation is supported by the guest-responsive properties ofβ-CDP-N.Moreover,the Au@β-CDP-N is easily recycled and maintained its high catalytic efficiency after seven successful cycles.