Green synthesis, spectroscopic analysis, and stabilisation energies of copper and manganese oxide nanoparticles from aqueous <i>Mentha piperita</i> leaf extract

Abstract

Manganese and copper oxide nanoparticles synthesized from the leaf extract of M. piperitha leaf extract were characterized using UV-visible spectrophotometry, FTIR, and SEM. In the UV- visible spectra strong absorption bands were observed at 600 and 403 nm for the manganese oxide and copper oxide nano particles respectively and these were ascribed to the plasmon resonance phenomenon, Significant but weak peaks observed at 617 cm^-1 in the FTIR spectra of CuO NPs and 538 cm^-1 in MnO NPs but totally absent from that of the plant extract were assigned to the metal – oxygen (M – O) stretching vibration. The detection of the M – O bond at low frequencies strongly confirms the formation of the NPs. The stabilization energies of the synthesized nano particles were calculated using Planck’s Quantization energy at their wavelengths of maximum excitation were found to be 299.3 and 200 kJ/mol at 400 nm and 600 nm for CuO and MnO NPS respectively