Immobilization of nanometer-sized metal catalysts into porous substrates can stabilize the catalysts and allow their recycled uses, while immobilization often sacrifices the active surface of catalysts and degenerates the local microenvironments, resulting in the reduction of the catalytic activity. To maintain a high activity of immobilized nanocatalysts, it is critically important to design an interface that minimizes the contact area and favors reaction chemistry. Here we report on the application of mussel-inspired adhesion chemistry to the formation of catalytic metal nanocrystal-polydopamine hybrid materials that exhibit a high catalytic efficiency during recycled uses. Electrospun polymer nanofibers are used as a template for in situ formation and immobilization of gold nanoparticles via polydopamine-induced reduction of ionic precursors. The prepared hybrid nanostructures exhibit a recyclable catalytic activity for the reduction of 4-nitrophenol with a turnover frequency of 3.2-5.1 μmol g(-1) min(-1). Repeated uses of the hybrid nanostructures do not significantly alter their morphology, indicating the excellent structural stability of the hybrid nanostructures. We expect that the polydopamine chemistry combined with the on-surface synthesis of catalytic nanocrystals is a promising route to the immobilization of various colloidal nanosized catalysts on supporting substrates for long-term catalysis without the physical instability problem.
Keywords: catalysis; electrospinning; metal nanoparticles; poly(ε-caprolactone); polydopamine.