Green synthesis of bimetallic PdcoreAushell nanoparticles for enhanced solid-phase photodegradation of low-density polyethylene film

Abstract

Bimetallic core/shell palladium/gold (PdcoreAushell) nanoparticles (NPs) were synthesized from aqueous solutions of Pd(II) and Au(III) species using Ananas comosus leaf extract as a reducing agent. The as-synthesized nanoparticles (NPs) were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible absorption (UV–Vis), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD). The bimetallic PdcoreAushell structure was confirmed with a UV–visible spectroscopy, and the surface Plasmon resonance (SPR) band occurred at around 517 nm, indicating the formation of Aushell layer on the surface of pre-formed Pd NPs. The sizes of the bimetallic PdcoreAushell NPs range from 2.06 to 28.59 nm with an average particle size of 13.15 ± 6.22 nm, and they crystallized in face-centred cubic (fcc) symmetry. The EDX analysis confirms the bimetallism of PdcoreAushell NPs with individual metal present in the ratio 1:2. The photocatalytic potential of the as-synthesized PdcoreAushell NPs was studied through the solid-phase degradation of low-density polyethylene (LDPE) film. We observed that the LDPE film with 1.0% PdcoreAushell NPs showed an enhanced degradation of 55.8 ± 5.9 compared with the pure LDPE with degradation of 8.6 ± 0.7 after solar light irradiation for a short period of 240 h. However, LDPE film with 1.0% PdcoreAushell NPs gave a degradation value of 1.90 ± 0.03 under the dark condition at the end of 240 h. The sustainability of the nanoparticles was confirmed through reusability in the photocatalytic degradation reaction up to five consecutive cycles without substantial loss in its catalytic performance. SEM characterization of the nanoparticles before and after degradation reaction showed the stability of the nanoparticles. The development of eco-friendly photodegradable plastic by incorporation of Pd@Au NPs into the polymer matrix is suggested in the current study for the polymer industry as a means of addressing challenges of plastic pollution.