Visible light-driven photocatalytic degradation of methylene blue dye over bismuth-doped cerium oxide mesoporous nanoparticles.

A series of Bi-doped ceria nanoparticles (0 to 20 wt% of Bi) were synthesized by sol-gel assisted hydrothermal method at a lower temperature of 150 °C. The synthesized nanoparticles were found to be effective photocatalysts for the degradation of methylene blue dye under visible light irradiation. The synthesized photocatalysts were well characterized by crystallographic, microscopic and spectroscopic methods. XRD patterns showed that the developed photocatalysts have cubic fluorite structure, and the absence of any impurity peaks in the XRD patterns of doped samples emphasizes the effective doping in host lattice. All samples exhibited mesoporous nature as evident from the adsorption and desorption pore size measurement. The shift of band gap energy from UV to visible region (2.90-2.77 eV) of the undoped and doped ceria results in the photo degradation of methylene blue dye in the visible light.