Synthesis and characterization of MoxFe1−xO nanocomposites for the ultra-fast degradation of methylene blue via a Fenton-like process: a green approach

Abstract

In the present work, a series of Mo_xFe_1−xO (x = 0.05, 0.10, 0.15) nanocomposite catalysts were prepared via a green method. The synthesized NPs were characterized by scanning electron microscopy (SEM), ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). The catalytic degradation of methylene blue (MB) dye solution was used to test the Fenton-like activities of the nanocomposites, and detailed studies of their kinetics and thermodynamics were conducted. In this study, green synthesis was adopted using Punica granatum peel (PGP) extract for the synthesis of the Mo_xFe_1−xO (x = 0.05, 0.10, 0.15) nanocomposites with the effective degradation of MB. The average crystalline size of the Mo_xFe_1−xO (x = 0.05, 0.10, 0.15) nanocomposites were in the range of 23–47 nm. The band gap values of the nanocomposites were found to be in the order of 3.31 eV to 3.34 eV. The Mo_xFe_1−xO (x = 0.05, 0.10, 0.15) nanocomposites were used for the removal of the MB dye via Fenton-like reactions as effective catalysts. Numerous variables, including the amount of catalyst used, changes in the dye concentration, the pH, the amount of H₂O₂, and the temperature all had a significant impact on the rate of degradation. We studied the degradation rate under a suitable condition of 10 mM to 30 mM of different nanocomposites, 20 mM [H₂O₂], and a temperature of 303.15 K. These conditions yield approximately 99% degraded product within 22 minutes of treatment. The activation energy was 7.95 kJ mol⁻¹, suggesting that the temperature-dependent effect of MB degradation is very small. The scavenger quenching experiment demonstrated that ˙OH radical production regulates the decomposition of the MB dye.