Photocatalytic dye degradation by magnetic XFe2O3 (X: Co, Zn, Cr, Sr, Ni, Cu, Ba, Bi, and Mn) nanocomposites under visible light: A cost efficiency comparison

Abstract

Magnetic photocatalyst-based dye degradation under visible light is a promising approach due to the ease of catalyst separation and recycling provided the catalyst is robust and cost-effective. To scrutinize and find a highly efficient and cost-effective magnetic photocatalyst, we have synthesized a series of X metal-doped Iron oxide-based nanocomposites XFe2O3 [X = Cobalt(Co), Zinc(Zn), Chromium(Cr), Strontium(Sr), Nickel(Ni), Cupper(Cu), Barium(Ba), Bismuth(Bi) and Manganese(Mn)] by simple precipitation based large scale feasible synthetic procedures. Afterward, those were meticulously characterized by various techniques such as UV–vis, Raman, Fourier Tranform Infrared Spectroscopy (FT-IR), Powder X-ray Diffraction (P-XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM). The magnetic susceptibility measurements showed that these XFe2O3 nanocomposites are ferromagnetic at room temperature. We tested their efficacy for photocatalytic dye (Methylene Blue) degradation under visible light irradiation and found that they can all be active at different pHs. Under natural sunlight also, the photocatalytic efficiency of ZnFe2O3 and CuFe2O3 for the removable of Methyl Orange was much higher than all other catalysts. A comparison of their relative cost and catalytic activity was plotted and BaFe2O3, MnFe2O3 and ZnFe2O3 were found to be the best magnetic photocatalysts for dye degradation under visible light while under sunlight, ZnFe2O3, CuFe2O3 and BaFe2O3 were found to be the best magnetic photocatalysts. The proposed formula clearly shows that, in addition to the percentage of degradation, the pricing of the catalyst is a crucial aspect to consider when selecting a catalyst. We also found that by maintaining the correct pH, the percentage of degradation increased efficiently.