Influence of synthesis parameters on the morphology, purity and phases type of Copper oxide nanoparticles

Abstract

In this study, copper oxide nanoparticles were synthesised by interaction of copper salt precursors with aqueous leaves extract of Khaya senegalensis. The influence of synthesis parameters such as solution pH (5, 9, 11, 13), copper salt types (chloride, nitrate and sulphate), calcination temperature (300^oC – 500^oC) and holding time (1-3 h) on the morphology and phase structure of CuO nanoparticles were examined. The as-synthesised materials were characterized by Energy Dispersive Microscopy (EDS), High Resolution Scanning Electron Microscope (HRSEM), Brunauer Emmett Teller (BET) N₂ adsorption-desorption technique, X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD). The HRSEM/XRD analysis of the calcined CuO nanoparticles confirmed the formation of spherical and crystalline stable tenorite phase at optimum calcination temperature (550^oC), and optimum holding time (3 h), pH (11) using copper sulphate salt precursors except for cupric acetate with no defined shape at  pH of 7 and 13. BET analysis revealed the formation of mesoporous material with surface area of 20.64 m²/g. XPS analysis demonstrated the existence of Cu  in the oxidation state of +2. This study established that the size and phase of CuO nanoparticles were dependent on the nature of the copper salts precursor, solution pH, calcination temperature and holding time.