Study of pH Influence in the Synthesis of Copper Nanoparticles Using Ascorbic Acid as Reducing and Stabilizing Agent

Abstract

The green chemical synthesis of copper nanoparticles (CuNPs) is an alternative which uses chemicals and processes that reduce or eliminate the use and generation of toxic substances, such as ascorbic acid, cyclodextrin, plant extracts, chitosan and gelatine. In this study, precursor solutions of copper sulfate pentahydrate and ascorbic acid were used. The synthesized CuNPs were characterized by UV-visible (UV-vis) absorption spectroscopy, scanning electron microscope coupled to an energy dispersive X-ray spectrometry (SEM-EDS) and X-ray diffraction (XRD). The presence of Cu oxide particles and Cu nanoparticles was inferred through UV-vis. In the images and compositions of the SEM-EDS, oxygen and Cu were found as well as particles of non-uniform size and morphology. The results showed that at pH 5, agglomerated CuNPs were found. XRD verification was performed on the particulate at pH 5 in which diffraction peaks were attributed to copper structure planes (with dimensions of 1042–3.34 nm) and other CuO and Cu2O diffraction peaks that overlapped with Cu phases. © 2020, The Minerals, Metals & Materials Society.