Effect of Ce and Mn co-doping on photocatalytic performance of sol-gel TiO2

Co-doped titanium dioxide was synthesized by doping with manganese (Mn) and cerium (Ce) through a sol-gel method for the degradation of diclofenac (DCF). The synthesized products were successfully characterized by X-ray diffraction (XRD), Raman spectroscopy, Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Nitrogen physisorption at 77 K, X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance (UV-DRS), photoluminescence spectroscopy (PL) and total organic carbon (TOC). It was shown that co-doping increased the specific surface area, improved the visible light absorption and extended the lifetime of photogenerated charge carriers. Furthermore, the results of the photocatalytic experiments show that the photodegradation rate of diclofenac can be approached by pseudo first-order kinetics and it followed the Langmuir-Hinshelwood model very well. The co-doped catalyst with 0.6% Mn and 1% Ce molar ratios appeared to be the most photoactive catalyst with 94% of DCF removal and an apparent rate constant of 0.012 min−1.