Green synthesis and characterization of copper oxide nanoparticles and their photocatalytic activity

Abstract

• CuO nanoparticles are successfully synthesized using green approach. • The energy band-gap was calculated to be 1.92 (papaya peel extract), and 1.22 eV (banana peel extract), respectively. • The degradation of MB is facilitated using CuO NPs under visible light. • Pseudo-first-order kinetics describes the degradation reaction satisfactorily. Copper Oxide (CuO) nanoparticles were synthesized through a green approach using the papaya and banana peel reducing as well as a stabilizing agents and copper (II) nitrate trihydrate salt as a precursor. The sample was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Transmission electron microscope (TEM), and UV–visible diffuse reflectance spectroscopy (DRS). The characterization results revealed about the CuO NPs structure, shape, energy gap, and functional group variations. The energy band-gap was calculated to be 1.92 (papaya peel extract), and 1.22 eV (banana peel extract), respectively. Under visible light irradiation, the photocatalytic activity of CuO NPs was investigated by degrading Methylene blue (MB) dye. It depicts that synthesized CuO NPs have a great potential for application as a photocatalyst to degrade textile colours in wastewater treatment in a short period. Moreover, the pseudo-first-order reaction rate constants were found to be 0.00359 min −1 (papaya peel extract) and 0.00335 min −1 (banana peel extract), respectively.