Photocatalytic degradation of malachite green and methylene blue over reduced graphene oxide (rGO) based metal oxides (rGO-Fe3O4/TiO2) nanocomposite under UV-visible light irradiation

Abstract

Reduced graphene oxide based iron oxide modified titania (rGO-Fe3O4/TiO2) was developed as a low-cost, stable, and reproducible photocatalyst, synthesized by conventional hydrothermal route. Structural and morphological features were investigated by X-Ray diffraction (XRD), Thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The incorporation of rGO-Fe3O4 to TiO2 shifted the light absorption of TiO2 from ultraviolet (UV) to visible region. The band gap energy of the synthesized photocatalyst rGO-Fe3O4/TiO2 reduced to 2.6 eV as compared to TiO2 (3.2 eV) which shifted the light absorption into visible region in order to utilize the solar energy effectually. The as-proposed rGO-Fe3O4/TiO2 and TiO2 photocatalysts were used for the photo-degradation of malachite green (MG) and methylene blue (MB) degradation. The as-prepared photocatalyst rGO-Fe3O4/TiO2 exhibited commendable photocatalytic efficiency (99%) comparative to pure TiO2 (67%) under visible light in 55 min for MG degradation. The active species were also identified using various scavengers by trapping holes and radicals generated during the photocatalytic degradation process. Subsequently, such photo-degradation output inferred that this ternary nanocomposite partakes a great potential for visible light driven MG and MB photocatalytic degradation.