Enhancement in wastewater refinement through a new cauliflower-like photocatalyst: TiO₂/Bi₂MoO₆/MnSe₂ heterojunction

In this research, a multiple-band-gap photocatalyst based on TiO₂, Bi₂MoO₆, and MnSe₂ was synthesized to extend the spectral response range of TiO₂-anatase as a wide-band-gap semiconductor for the dye degradation under visible irradiation. Its structure was confirmed by various identification methods including XRD, FT-IR, EIS, PL, SEM, TEM, and EDX. The photocatalytic properties of the composites were also confirmed by the DRS, PL, and COD investigations. Nyquist and Tauc plots showed superconductivity, and a long life time of excited electron. Also, flat band energy and donor density of nanocomposite were evaluated from Mott-Schottky plot which confirmed its photoactivity. The photocurrent jumps immediately when light was turned on which indicating a good photoelectric response. After four times recovery, the recovered catalyst can still decompose Rh.B with 92% efficiency. The effects of different factors such as the initial pH, amount of the photocatalyst loading, the initial concentration of the dye, and irradiation time, besides the photocatalyst composition, were also studied. Mechanism investigation showed holes and °OH play considerable effect on the mechanism of photocatalytic degradation.