Synthesis, Characterization and Photocatalytic Studies of La, Dy-doped ZnO nanoparticles

Rare earth La Dy co-doped ZnO nanoparticles (Zn0.98La0.01Dy0.01O, Zn0.96La0.02Dy0.02O, Zn0.94La0.03Dy0.03O, and Zn0.92La0.04Dy0.04O) were synthesized by co-precipitation method at temperature of 500 degrees C for 2 h in air. The synthesized samples were characterized by powder X-ray diffraction (XRD), FE-SEM/EDS and UV-Visible spectrophotometer. The prepared nanoparticles exhibit a hexagonal wurtzite structure as observed from XRD measurements. It was observed that the La Dy co- doped ZnO nanoparticles (Zn0.98La0.01Dy0.01O, Zn0.96La0.02Dy0.02O, Zn0.94La0.03Dy0.03O, and Zn0.92La0.04Dy0.04O) exhibit higher optical absorbance spectrum at 400 nm to 800 nm wavelength due to its smaller crystal size (12.2 nm) as compared to the un- doped ZnO nanoparticles (253.1 nm). The photocatalytic activity of rare earth La Dy co- doped ZnO nanoparticles were studied by performing the decomposition of methylene blue dye solution under UV light irradiation within 0-4 h. The methylene blue dye solution was considerably photodegraded by Zn0.92La0.04Dy0.04O photocatalyst under UV light irradiation within 2-4 h to the efficiency of 96 %. The pseudo first order rate constant of the degradation was found to be 0.0264 S-1. The degradation mechanisms are discussed in this work.