Green synthesis of single phase hausmannite Mn3O4 nanoparticles via Aspalathus linearis natural extract

Abstract

Nowadays, green synthesis of nanoparticles using plant precursors has been extensively studied. However, less attention has been given to Mn3O4. This contribution validates the synthesis of single-phase Hausmannite Mn3O4 nanoparticles by a green approach without using any standard acid/base compounds, surfactants, and organic/inorganic dissolving agents. The chemical chelation of the Mn precursor was performed via bioactive compounds of the Aspalathus Linearis’ extract, an African indigenous plant. Annealing at 400 °C for ~ 1 h was required to crystallize the small amorphous nanoparticles with an initial bimodal size distribution peaking at $$\left\langle {\phi_{1} } \right\rangle$$ ϕ 1 ~ 4.21 nm and $$\left\langle {\phi_{2} } \right\rangle$$ ϕ 2 ~ 8.51 nm respectively. Such annealing lead to increase in the diameter of the nanoparticles from 17 to 28 nm.The morphological, structural, vibrational, surface, and photoluminescence properties of the single-phase Hausmannite nanoparticles were comprehensively investigated by High Resolution Transmission Electron Microscopy(HRTEM),Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), Raman and X-rays Photoelectron Spectroscopy (XPS), spectroscopy as well as room temperature photoluminescence. Structural and morphological investigations revealed the formation of quasi-spherical nanoparticles having a single phase Hausmannite Mn3O4 crystal structure. XPS results also validated the XRD results about the formation of Hausmannite Mn3O4 nanoparticles. Raman investigations allowed a crystal-clear distinction between the Mn3O4 nature of the nanoparticles from the potential γ -Mn2O3 phase as both phases belong to the same space group and both assume tetragonally-distorted cubic lattices of nearly similar dimensions. The optical studies of the single phase Hausmannite crystalline nanoparticles exhibited a broad photoluminescence in the spectral range of 300–700 nm, which is ideal for emission devices. Graphic abstract

Synthesis of Spherical Mn2O3 Nanozymes from Different Green Precursors for their Innovative Applications in Catalytic Properties and Bioactivity

“…The portions of the spectra that corresponded to the characteristic peaks of C, N, and O atoms were around 0−2 keV. The distinctive peaks of Mn atoms were likewise associated with the peaks that emerged in the 1.1, 5.9, and 6.5 keV 31 regions.…”

Biochar Derived from Palm Waste Supported Greenly Synthesized MnO2 Nanoparticles as a Novel Adsorbent for Wastewater Treatment

“…These EDX peaks are attributed to the quartz and calcite composition of the raw material and its biochar [37,38], while the presence of manganese element on the MnO 2 /PF biochar nanocomposite surface confirmed the effective synthesis of the MnO 2 NPs [39]. The presence of Au peaks originates from the Au coating, which was performed to minimize the surface electron charging via the EDS [40].…”

Review on Medical Applications of Manganese Oxide (Mn2+, Mn3+, and Mn4+) Magnetic Nanoparticles

“…(Fishtail palm) flower [88], Leucaena Leucocephala [89], and green tea [90]. Diallo et al [91] prepared Mn 3 O 4 NPs in the diameter of 18-28 nm by Aspalathus linearis extract using the precursor, manganese chloride. The formation mechanism of Mn 3 O 4 NPs using A. linearis extract is represented in Figure 11.…”