Influence of green synthesis factors on formed of copper nanoparticles (Cu NPs)

Abstract

This study presents a green synthesis method for copper nanoparticles (Cu NPs) using butterfly pea flower (Clitoria ternatea) extract as a reducing and stabilizing agent. The effects of different copper salts (CuSO₄, CuCl₂, Cu(CH3COO)2, Cu(NO₃)₂) and the volume ratio between the plant extract and copper salt solution on CuNPs formation were investigated. XRD analysis confirmed the formation of face-centered cubic crystalline CuNPs with crystallite sizes ranging from 30 to 40 nm. FESEM images revealed non-uniform particle morphology with sizes ranging from several hundred nanometers to approximately 1 µm. FTIR and Raman spectroscopy demonstrated the role of functional groups in the reduction and stabilization processes. Among the salts examined, Cu(NO₃)₂ produced smaller and more uniform nanoparticles, especially at a plant extract-to-salt volume ratio of 2:1. This work contributes to the development of eco-friendly nanomaterials using plant-based synthesis routes.