Arc Discharge Synthesis of Chitosan-Mediated Copper Nanoparticles for Heterogeneous Catalysis in 4-Nitrophenol Degradation

Abstract

Copper nanoparticles (Cu-NPs) have garnered substantial interest in the field of nanotechnology due to their exceptional physical and chemical properties and cost-effectiveness. However, challenges such as particle aggregation and rapid copper oxidation affect nanoscale production. This study systematically investigates the synthesis of colloidal Cu-NPs using chitosan (Cts) as a stabilizer and reducing agent in the arc discharge system, comparing it to distilled water as a medium. Confirmation of the purity, size, and morphology of the Cu-NPs is achieved through various physicochemical characterization methods. X-ray diffraction patterns confirm the synthesis of highly pure face-centered cubic (fcc) crystal Cu-NPs. UV–vis analysis reveals absorption peaks at 572–585 nm, indicating pure copper. Fourier-transform infrared spectroscopy shows peaks at 638 and 597 cm⁻¹, corresponding to Cu─Cts bonds. Transmission electron microscopy images depict spherical nanoparticles ranging from 15 to 45 nm, with smaller sizes at higher Cts concentrations. The catalytic activity of Cu-NPs in the degradation of 4-nitrophenol to 4-aminophenol is assessed, with Cu-NPs synthesized in distilled water demonstrating superior catalytic properties compared to 0.10 wt.% Cts. This study highlights the efficacy of the arc discharge method in producing pure, uniformly sized Cu-NPs with potential applications in catalysis.