Synthesis, Characterization and Photodegradation Potential of Mn₂O₃ and MnFe₂O₄ Nanoparticles

The present study focuses on the synthesis, characterization, and photocatalytic evaluation of Mn₂O₃ and MnFe₂O₄ Nanoparticles (NPs). The NPs were synthesized using co-precipitation and subsequently characterized through various analytical techniques, including UV-Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Furthermore, the photocatalytic efficiency of the synthesised NPs was evaluated by degrading malachite green dye under visible-light irradiation. The average crystallite sizes of Mn₂O₃, and MnFe₂O₄ NPs were 60 nm and 90 nm, respectively. The FT-IR spectra showed bending and stretching vibration modes of O–H, Mn–O, and Mn–O–Mn groups in the synthesized NPs. The SEM image of the Mn₂O₃ NPs appeared as spherical grains with a porous and non- uniform surface. The particles were densely packed, and some agglomeration was observed due to particle clustering. The SEM image of the MnFe₂O₄ NPs showed a needle-like and network- shaped morphology. Two strong peaks were visible in the Mn₂O₃ NPs UV–vis absorption spectra at around 263 and 289 nm. The sharp absorption at 263 nm is assigned to O^2- →Mn³⁺ charge transfer transitions within Mn₂O_3, whereas for MnFe₂O₄ NPs two peaks around 209 and 264 nm were observed. The photodegradation studies showed approximately 83% degradation in the presence of Mn₂O₃ NPs, within 120 minutes, whereas MnFe₂O₄ NPs degraded 82 % of malachite green within 105 minutes, showing their potential in water pollution remediation.