Visible light active Ni2+ doped CeO2 nanoparticles for the removal of methylene blue dye from water

The treatment of organic dye pollutants in water, by photocatalysis is getting much attention nowadays. In the present study, a series of visible light active Ni2+ doped ceria (CeO2) photocatalysts were synthesized by combining sol-gel and hydrothermal methods. X-ray diffraction patterns of the Ni2+ doped and undoped ceria nanoparticles represent a cubic fluorite structure. The thermal stability of the photocatalysts has been confirmed from thermogravimetric analysis (TGA) and the X-ray photoelectron spectroscopy (XPS) analysis confirms the effective doping of Ni2+ in ceria. Surface morphology and particle size were determined by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Compared to undoped ceria, Ni2+ doped ceria samples showed strong visible range absorption, among them, 5 wt % Ni2+ doped ceria exhibits the highest absorption. The photocatalytic activity of the samples was evaluated under direct sunlight, using methylene blue dye as a model system. 5 wt % Ni2+ doped ceria had the maximum photocatalytic activity, with 85.83% degradation efficiency.