Photocatalytic Study of Rose Bengal Dye using Sol–Gel-Synthesized Titanium dioxide incorporated with Transition metal elements (Manganese and Cobalt)

This study is concerned with the photocatalytic degradation of rose bengal dye using modified titanium dioxide, specifically using different metal ions, like manganese (Mn) and cobalt (Co). The TiO₂/Mn/Co composites were prepared via a sol–gel route since it favors the homogenous introduction of metal ions into the TiO₂ matrix. For the preparation of the composites, titanium dioxide (0.89 mol) was mixed with manganese (II) chloride (0.05 mol) and cobalt chloride hexahydrate (0.06 mol). The structural and morphological properties of the synthesized photocatalysts were assessed by characterization techniques such as X-ray diffraction (XRD) and transmission electron microscopy (TEM), Fourier-Transform Infrared (FT-IR) and UV-VIS spectroscopy. The average particle size was found to be 74.8 nm, which was calculated using image J software, and the interplanar d-spacing was 0.3567 nm, as calculated from HR-TEM images. The TEM images also revealed the spherical morphology of the composite. Optical studies have revealed the narrowed band gap of the TiO₂/Mn/Co nanocomposite. Photocatalytic performance under sunlight was evaluated, indicating enhancement in the efficiency of rose bengal degradation compared to pure TiO₂ through the incorporation of manganese and cobalt. The degradation efficiency was 92% in the case of TiO₂ and increased to 94% with the TiO₂/Mn/Co nanocomposite. The suggested mechanism for the degradation process, through the generation of reactive oxygen species during sunlight irradiation, elucidates an essential role of the latter in breaking down the molecular structure of the dye. Overall, these results prove that TiO₂/Mn/Co composites may have the potential to offer an effective solution for dye removal from wastewater, thereby making a positive contribution towards environmental sustainability.