Investigation of structural and optical properties of biosynthesized Zincite (ZnO) nanoparticles (NPs) via an aqueous extract of Rosmarinus officinalis (rosemary) leaves

Abstract

Biosynthesized Zincite nanoparticles have been successfully demonstrated by a completely green process mediated aqueous extract of rosemary leaves acting as both reducing and stabilizing agents and zinc nitrate hexahydrate as the precursor. The synthesis was free of solvents and surfactants to adhere to green chemistry principles and the impartation of environmental benignity. To achieve our objective, structural and optical investigations of ZnO annealed at 500°C for 2hrs were carried-out using complementary techniques. High resolution transmission electron microscopy (HRTEM) revealed the self-assembled, highly agglomerated quasi-hexagonal shaped NPs and the average particle size was found to peak at 15.62 ± 0.22 nm. Selected area electron diffraction (SAED) and X-ray diffraction (XRD) exhibited several diffraction rings with clear diffraction spots confirming their polycrystallinity and the purity of ZnO NPs with a wurtzite structure. Furthermore, the energy dispersive X-ray spectroscopy (EDS) substantiated the presence of Zn and O in the sample and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) illustrated the Zn-O chemical bonds. From UV-Vis-NIR, the optical band gap was amounted to 3.2 eV and photoluminescence (PL) emission spectrum to 2.9eV with high surface defects and oxygen vacancies. Through these results, the use of rosemary leaves extract is hereby shown to be a cost-effective and environmentally friendly alternative to synthesize Zincite nanoparticles (ZnO NPs).

Adsorptive potential of ZnO/SiO2 nanorods prepared via the sol–gel method for the removal of Pb(II) and Cd(II) from petroleum refinery wastewater

“…The ZnO nanoparticle crystallite size was determined to be 16.52 nm (see Eqn 13). These findings are in accordance with the report by Noukelag et al 53 . who synthesized ZnO nanoparticles via the green method using extract of Rosmarinus officinalis leaves.…”

“…The ZnO nanoparticle crystallite size was determined to be 16.52 nm (see Eqn 13). These findings are in accordance with the report by Noukelag et al 53 who synthesized ZnO nanoparticles via the green method using extract of Rosmarinus officinalis leaves. However, their analysis revealed that the ZnO nanoparticles had stronger diffraction and higher crystallinity than the ZnO nanoparticles prepared in the present study.…”

Green synthesis and characterization of zinc oxide nanoparticles using leaf extract of Thryallis glauca (Cav.) Kuntze and their role as antioxidant and antibacterial

“…The calculated band gap of ZnO NPs without calcination and calcinated ZnO NPs was 3.1 and 3.5 eV, respectively, close to pure ZnO (3.3 eV). The material's band-gap depends on factors, such as surface roughness, oxygen vacancy, lattice strain, grain size (Faisal et al, 2021;Noukelag et al, 2020), and calcination temperature. de Almeida et al reported that an increase in band-gap could be due to a rise in the calcination temperature (de Almeida et al, 2021).…”

Synthesis of 5,15-A2BC-Type Porphyrins to Modify a Field-Effect Transistor for Detection of Gram-Negative Bacteria

“…60 % sample has intense orange colour which is quite typical for the natural ZnO mineralzincite [18], but up to our knowledge was never reported for the ZnO films produced by magnetron sputtering. The possibility of observation of zincite phase is also indirectly rejected by the mismatch between reported band gap of zincite which is approximately 3.2 eV [19] and experimentally observed value of 3.08 eV. Also, the presence of zincite phase is not confirmed by XRD (Fig.…”