Structural and antibacterial properties of copper oxide nanoparticles: a study on the effect of calcination temperature

Abstract

Nanoparticles of copper oxide were synthesized by the simple precipitation method. The influence of calcination temperature on the structural characteristics and antibacterial activity of the nanoparticles were evaluated. The nanoparticles were analyzed by Bruner-Emmett-Teller (BET) surface area and pore size analyzer, x-ray diffraction, transmission electron microscope and scanning electron microscope. The findings demonstrated the formation of copper oxide nanoparticles showing a monoclinic phase. Before calcination, the nanoparticles showed a high BET surface area with rod shape morphology and size range between 18–70 nm and after calcination, irregular spherical-like morphology with size range of 20–200 nm was observed. However, it was evident that the BET surface area decreased gradually with increasing calcination temperature, while the nanoparticle size increased forming an irregular spherical shape. Subsequently, the copper oxide nanoparticles demonstrated that they are highly effective for bacteria inactivation. The inactivation activity was found to be more effective with uncalcined nanoparticles than with calcined nanoparticles. This was due to the large nanoparticle sizes and the decrease in surface area obtained after calcination. Thus, it was noted that calcination of the as-prepared nanoparticles significantly affects the structural and antibacterial properties. Hence, for antibacterial application, calcination was not necessary as the nanoparticles showed excellent antibacterial results.