Synthesis of Au/Co3O4/PVA hybrid nanocomposites via eco-friendly method based on pulsed laser ablation process for water treatment

Abstract

A portable nanostructured nanocomposite film, based on cobalt oxide and gold nanoparticles (NPs) embedded in a polyvinyl alcohol structure (PVA), Au/Co3O4/PVA, was prepared via a novel way based on pulsed laser ablation to be applied as an effective catalytic degradation material for a hazardous chemical structure as nitro compounds. Au/Co3O4/PVA was investigated by the techniques of UV–Vis, FT-IR, SEM, and XRD. From XRD, the decrease in crystallinity of PVA is attributed to the intermolecular hydrogen bonding between PVA and Au/Co3O4. In addition, there are five interplanar peaks, with three shared peaks by both phases and one unique peak for each phase of Au and Co3O4. From FT-IR, the modes observed at a 500–1200 cm-1 wavenumber range correspond to the stretching vibration modes of Au/Co3O4. From UV–VIS, as the embedding of Co3O4 on Au-PVA structure increases, the energy band gap is shifted to a lower value. This is due to the embedding of Co3O4 NPs. From SEM, in the case of embedding PVA with Au NPs, the bright semi-spherical shape of the nanostructured materials has a bright semi-spherical light area. Moreover, in the case of the embedded PVA with Co3O4 NPs, the faint semi-spherical form of the nanostructured materials is discernible. Besides, the catalytic activity performance is tested for the degradation of 4-nitrophenol, which reveales that the reaction followed first-order kinetics, as indicated by linear regression analysis. The results shows that the sample completely convertes 4-nitrophenol to 4-aminophenol within 6 min.