Visible light enhanced photocatalytic degradation of methylene blue by ternary nanocomposite, MoO₃/Fe₂O₃/rGO

Abstract

Herein we report the first in situ hydrothermal-assisted synthesis of a MoO3/Fe2O3/rGO ternary nanocomposite. The composite was prepared with various amounts of rGO loaded (1%, 3%, 5%, 7% and 10%), which were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectrophotometer, transmission electron microscopy, UV-visible diffuse reflectance spectrophotometer, thermogravimetric analysis (TGA), Raman, Photoluminescence and Brunauer–Emmett–Teller analysis to study the structural, morphological and optical properties. FESEM micrographs reveal a regularly uniform belt-type structure in which MoO3 with relatively smooth surfaces and Fe2O3 were agglomerated, which led to complete dispersion with the rGO and formed ternary nanocomposites, MoO3/Fe2O3/rGO. The elemental composition of the ternary nanocomposite (Mo, Fe, O and C) was determined from EDX. XRD results show the average crystallite size to be 22.3 nm for the ternary nanocomposite and about the same for the pure phase formation. The synthesized samples were examined for degradation of a model dye, methylene blue (MB) under visible light illumination. The photocatalytic degradation efficiency of as-synthesized materials was determined by measuring the absorption spectra of MB, and the results showed that MoO3/Fe2O3/rGO-5% ternary nanocomposite exhibited higher MB photodegradation efficiency (99.47%) under visible light illumination than other four rGO-loaded ternary nanocomposites, MoO3/Fe2O3 binary composite, Fe2O3 and MoO3.