Green preparation and characterization of tentacle-like silver/copper nanoparticles for catalytic degradation of toxic chlorpyrifos in water

Abstract

The synthesis of bimetallic nanoparticles is gaining attention due to a number of interesting and striking new properties that can be derived from the combination of two metals. In this study, bimetallic silver/copper (Ag/Cu) nanoparticles were prepared by co-reduction method using aqueous leaf extracts of Carica papaya as reducing agent. The synthesized nanoparticles showed a single UV–vis peak with a maximum absorption at 776nm. The SEM and TEM images of bimetallic Ag/Cu nanoparticles displayed, among others, a unique star-like structure. HR-TEM mapping revealed uniform distribution of Ag & Cu forming a bimetallic nanoparticle. The bimetallic Ag/Cu has an average hydrodynamic particle size of 420.7nm (DLS) and TEM size of ∼150nm. The presence of elemental Ag, Cu, C, N and O was confirmed in EDX spectra suggesting nitrogen containing metabolites capping the bimetallic Ag/Cu nanoparticles. The XRD patterns of bimetallic Ag/Cu nanoparticles displayed crystallinity with observed diffraction peaks corresponding to Ag, Ag2O and CuO. The synthesized bimetallic nanoparticles were then utilized for water purification application using the toxic pollutant, chlorpyrifos pesticide, as a model. Results showed that bimetallic Ag/Cu nanoparticles are efficient agents to promote degradation of chlorpyrifos in water, indicating the high potential of green synthesized nanometals for purifying water from pesticide contamination.