Bio-inspired synthesis of PbO nanoparticles (NPs) via an aqueous extract of Rosmarinus officinalis (rosemary) leaves

Abstract

There is a pressing need for the development of nanoparticles (NPs) for environmental nanoscience and nanotechnology. Bio-inspired synthesis of lead oxide nanoparticles has been successfully demonstrated using an aqueous extract of Rosmarinus officinalis (rosemary) leaves. Structural and optical investigations of lead oxide annealed at 600 °C were carried-out using complementary techniques namely, X-ray diffraction (XRD) that showed the formation of both form α-PbO (tetragonal) and β-PbO (orthorhombic) NPs with the average crystalline size found approximately at 8.96 nm whereas field emission scanning electron microscopy (FESEM) revealed NPs highly agglomerated with the average particle size found to peak at 12.69 ± 0.27 nm. Energy dispersive X-ray spectroscopy (EDS) confirmed the high purity of PbO as well as attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. From UV–Vis-NIR, the energy bandgap has amounted to 4.44 eV and the photoluminescence (PL) emission spectrum showed broad nature of visible emissions peaks at 361, 448, 562 and 689 nm with high surface defects and oxygen vacancies. Through these findings, the use of Rosemary leaves extract is hereby shown to be a cost-effective and environmentally benign alternative to synthesize lead oxide nanoparticles (PbO NPs).