Preparation, characterization and photocatalytic properties of Er-doped ZnO nanoparticles synthesized by combustion method

Erbium-doped zinc oxide (Er-doped ZnO) as a visible-light-driven photocatalyst was prepared by combustion method and followed by calcination at 600 degrees C for 2 h. The samples were characterized by means of X-ray diffraction, Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. X-ray diffraction patterns of ZnO samples with and without Er dopant confirm the formation of pure hexagonal wurtzite ZnO phase. The X-ray diffraction peaks of ZnO were shifted to the lower 2 theta angle when Er was doped to ZnO matrix. Their transmission electron microscopy images show that the addition of Er can play a role in significantly changing their particle size. Average particle sizes of the as-prepared samples were 69.15 +/- 14.47 nm, 68.33 +/- 17.06 nm, 16.38 +/- 4.02 nm and 27.00 +/- 5.27 nm for 0 %, 1 %, 3 % and 5 % Er-doped ZnO samples, respectively. Raman spectra of the Er-doped ZnO samples were able to be used to identify the presence of defect and structural disorder in the ZnO lattice. The ZnO samples with and without Er dopant were tested for the degradation of methylene blue under visible light irradiation. Upon increasing the doped Er content, the degradation of methylene blue solution under visible light irradiation was enhanced. In this research, the 3 % Er-doped ZnO nanoparticles have the highest efficiency of 98.26 % under visible light irradiation within 100 min.