PVP-crosslinked electrospun membranes with embedded Pd and Cu2O nanoparticles as effective heterogeneous catalytic supports

Abstract

Palladium(0) (Pd) and copper(I) oxide (Cu₂O) nanoparticles (NPs) were successfully embedded in electrospun polyvinylpyrrolidone (PVP) fibrous membranes. The fabrication process involved the synthesis of stable, PVP-capped Pd and Cu₂O colloidal hybrid solutions in methanol that on subsequent electrospinning afforded PVP–Pd and PVP–Cu₂O fibrous mats. The morphology of the as-prepared nanocomposite fibers was characterised using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM revealed the presence of bead-free, cylindrical fibers with diameters in the submicrometer range while TEM revealed the presence of spherical Pd and Cu₂O NPs with diameters below 10 nm that were evenly distributed within the fibers. Thermal treatment of the PVP–Pd and the PVP–Cu₂O membranes afforded crosslinked fibrous mats as supported by SEM. Furthermore, the presence of homogeneously distributed Pd and Cu₂O NPs within the crosslinked polymer fibers was confirmed by HRTEM/EDX analyses. The above-mentioned nanocomposite fibers demonstrated high catalytic efficacy as heterogeneous catalytic supports in Heck, Suzuki (PVP–Pd) and click (PVP–Cu₂O) reactions. Finally, the reusability of the membranes was briefly investigated with up to three consecutive runs being effective.