Mo, Mn and La doped TiO2: Synthesis, characterization and photocatalytic activity for the decolourization of three different chromophoric dyes

• Detail study on synthesis, characterization & photocatalytic activity of doped-TiO2.
• SEM images indicates partial crystalline nature with rough surfaces.
• The XRD analysis shows the partial crystalline nature and anatase phase.
• The UV–Vis absorption spectra showed λmax shift towards longer wavelength.
• TiO2 with dopant 0.75% (Mo), 1.0% (Mn, La) showed best photocatalytic efficiency.

Nanocrystalline TiO2 particles doped with different concentrations of Molybdenum (Mo), Manganese (Mn) and Lanthanum (La) (0.25–1.0%) were synthesized using sol–gel method and characterized by standard analytical techniques such as X-ray diffraction (XRD), UV–Vis spectroscopy and Scanning Electron Microscopy (SEM). The XRD analysis shows the partial crystalline nature and anatase phase. The SEM images of undoped and doped TiO2 at different magnifications also show the partial crystalline nature with rough surfaces. The photocatalytic activity of the synthesized particles (TiO2 doped with Mo, Mn and La) was tested by studying the decolourization of three different chromophoric dyes such as Acid Red 88 (azo dye), Gentian Violet (triphenylmethane dye) and Remazol Brilliant Blue R (anthraquinone dye) as a function of time on irradiation in aqueous suspension in an immersion well photochemical reactor with a 500 W halogen linear lamp in the presence of atmospheric oxygen. The results indicate that TiO2 with dopant concentration of 0.75% (Mo) and 1.0% (Mn, La) showed the highest photocatalytic activity as compared to the other dopant concentrations for the decolourization of all the dyes.