Enhanced Visible-light-driven Photocatalytic Activity of Multiferroic KBiFe₂O₅ by Adjusting pH Value

Multiferroic KBiFe 2 O 5 was successfully prepared by a facile hydrothermal method. Its phase purity and morphology were investigated by powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The visible-light absorption was confirmed by UV-Vis diffuse reaction spectroscopy (UV-Vis DRS). Effect of pH value on visible-light-driven photocatalytic properties of KBiFe 2 O 5 was evaluated by degrading rhodamine B (RhB) and methyl orange (MO). It can be found that lower pH value contributed to smaller average particle size. The D 50 of the sample at pH 7 is about 10 times larger than that at pH 2. Acid condition is beneficial to the dispersion of KBiFe 2 O 5 nanoparticles, which leads to an enhanced photocatalytic performance. Photocatalytic activity of KBiFe 2 O 5 is significantly improved by decreasing pH value of the solution, which is attributed to the promoted dispersion of catalyst particles in the suspension and the enhanced adsorption of dye molecules on the catalyst surface.